Hinsberg Sulfone Synthesis I sulfonylquinol I Reaction I Chemical Reaction

O. Hinsberg, Ber. 27, 3259 (1894); 28, 1315 (1895).
Formation of sulfonylquinol derivatives by addition of quinones to cold dilute aqueous solutions of sulfinic acids:
Hinsberg Sulfone Synthesis
R. M. Scribner, J. Org. Chem. 31, 3671 (1966); H. Ulrich et al., Houben-Weyl 7/3a, 661 (1977). Cf. Thiele Reaction.

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Hinsberg Synthesis of Thiophene Derivatives I carboxylic acids I Reaction I Chemical Reaction

O. Hinsberg, Ber. 43, 901 (1910).
Formation of thiophene carboxylic acids from ?-diketones and dialkyl thiodiacetates:

Hinsberg Synthesis of Thiophene Derivatives
H. Wynberg, D. J. Zwanenburg, J. Org. Chem. 29, 1919 (1964); H. Wynberg, H. J. Kooreman, J. Am. Chem. Soc. 87, 1739 (1965); A. Birch, D. A. Crombie, Chem. Ind. 1971, 177; D. J. Chadwick et al., J. Chem. Soc. Perkin Trans. I 1972, 2079

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Chromium I Nozaki-Hiyama Coupling Reaction (Nozaki-Hiyama-Kishi Reaction) I Reaction I Chemical Reaction

Y. Okude et al., J. Am. Chem. Soc. 99, 3179 (1977); K. Takai et al., Tetrahedron Letters 24, 5281 (1983).

Chromium chloride catalyzed redox additions or organic halides to aldehydes:

Nozaki-Hiyama Coupling Reaction (Nozaki-Hiyama-Kishi Reaction)

Use of nickel salts as catalyst: H. Jin et al., J. Am. Chem. Soc. 108, 5644 (1986); K. Takai et al., ibid. 6048; of chromium: A. Furstner, N. Shi, ibid. 118, 12349 (1996). Enantioselectivity: K. Sugimoto et al., J. Org. Chem. 62, 2322 (1997); M. Bandini et al., Angew. Chem. Int. Ed. 38, 3357 (1999). Synthetic applications: Y. Kishi, Pure Appl. Chem. 64, 354 (1992); D. P. Stamos et al., J. Org. Chem. 62, 7552 (1997). Review: N. A. Saccomano, Comp. Org. Syn. 1, 173-207 (1991).

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Hoch-Campbell Aziridine Synthesis I hydrolysis I Reaction & Chemical Reaction

J. Hoch, Compt. Rend. 198, 1865 (1934); K. N. Campbell, J. F. McKenna, J. Org. Chem. 4, 198 (1939).

Formation of aziridines by treatment of ketoximes with Grignard reagents and subsequent hydrolysis of the organometallic complex:

Hoch-Campbell Aziridine Synthesis

K. N. Campbell et al., J. Org. Chem. 8, 99, 103 (1943); 9, 184 (1944); J. P. Freeman, Chem. Rev. 73, 283 (1973); O. C. Dermer, G. E. Ham, Ethylenimine and Other Aziridines (Academic Press, New York, 1969) pp 65-68; E. Y. Takehisa et al., Chem. Pharm. Bull. 24, 1691 (1976); T. Sasaki et al., Heterocycles 11, 235 (1978); G. Alvernhe, A. Laurent, J. Chem. Res. (S) 1978, 28.

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Houben-Hoesch Reaction I Synthesis of acylphenols I Reaction & Chemical Reaction

K. Hoesch, Ber. 48, 1122 (1915); J. Houben, ibid. 59, 2878 (1926).

Synthesis of acylphenols from phenols or phenolic ethers by the action of organic nitriles in the presence of hydrochloric acid and aluminum chloride as catalyst:

Houben-Hoesch Reaction

Reviews: P. E. Spoerri, A. S. DuBois, Org. React. 5, 387 (1949); Thomas, Anhydrous Aluminum Chloride in Organic Chemistry (New York, 1941) p 504; W. Ruske in Friedel-Crafts and Related Reactions vol. III, Part 1, G. A. Olah, Ed. (Interscience, New York, 1964) p 383; M. I. Amer et al., J. Chem. Soc. Perkin Trans. I 1983, 1075; V. V. Arkhipov et al., Chem. Heterocycl. Compd. 33, 515 (1997); R. Kawecki et al., Synthesis 1999, 751. Cf. Gatterman Aldehyde Synthesis; Houben-Fischer Synthesis.

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Hofmann Degradation (Exhaustive Methylation) I Reaction & Chemical Reaction I pyrolysis

A. W. Hofmann, Ber. 14, 659 (1881).

Formation of an olefin and a tertiary amine by pyrolysis of a quaternary ammonium hydroxide:

Hofmann Degradation (Exhaustive Methylation)

A. C. Cope, E. R. Trumbull, Org. React. 11, 317-493 passim (1960); K. W. Bentley, G. W. Kirby in Techniques of Organic Chemistry vol. IV, Pt. 2, A. Weissberger, Ed., Elucidation of Organic Structures by Physical and Chemical Methods (Wiley, New York, 2nd ed., 1973) pp 255-289. Isotope effects: R. D. Bach, M. L. Braden, J. Org. Chem. 56, 7194 (1991). Synthetic applications: A. D. Woolhouse et al., J. Heterocyclic Chem. 30, 873 (1993); D. Berkes et al., Synth. Commun. 28, 949 (1998). Cf. Cope Elimination Reaction; Emde Degradation.

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Hofmann Isonitrile Synthesis (Carbylamine Reaction) I Reaction & Chemical Reaction

A. W. Hofmann, Ann. 146, 107 (1868); Ber. 3, 767 (1870).
Formation of isonitriles by the reaction of primary amines with chloroform in the presence of alkali; the odor of the isocyanide is a test for a primary amine:

Hofmann Isonitrile Synthesis (Carbylamine Reaction)

P. A. S. Smith, N. W. Kalenda, J. Org. Chem. 23, 1599 (1958); M. B. Frankel et al., Tetrahedron Letters 1959, 5; H. L. Jackson, B. C. McKusick, Org. Syn. coll. vol. IV, 438 (1963); W. P. Weber, G. W. Gokel, Tetrahedron Letters 1972, 1637.

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Hofmann Reaction I carboxylic amides I Reaction & Chemical Reaction

A. W. Hofmann, Ber. 14, 2725 (1881).
Conversion of primary carboxylic amides to primary amines with one fewer carbon atom upon treatment with hypohalites or hydroxide via the intermediate isocyanate:

Hofmann Reaction
Early review: E. S. Wallis, J. F. Lane, Org. React. 3, 267-306 (1949). Alternative reagents/strategies: S. Kajigaeshi et al., Chem. Letters 1989, 463; S. Jew et al., Arch. Pharm. Res. 15, 333 (1992); D. S. Rane, M. M. Sharma, J. Chem. Tech. Biotechnol. 59, 271 (1994); H. Moustafa et al., Tetrahedron 53, 625 (1997); Y. Matsumura et al., J. Chem. Soc. Perkin Trans. I 1999, 2057. Review: T. Shioiri, Comp. Org. Syn. 6, 800-806 (1991). Cf. Curtius Rearrangement; Lossen Rearrangement; Schmidt Reaction; Weerman Degradation.

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Hofmann-Löffler-Freytag Reaction I pyrrolidines I Reaction & Chemical Reaction

A. W. Hofmann, Ber. 16, 558 (1883); 18, 5, 109 (1885); K. Löffler, C. Freytag, ibid. 42, 3427 (1909).

Formation of pyrrolidines or piperidines by thermal or photochemical decomposition of protonated N-haloamines:

Hofmann-Löffler-Freytag Reaction
M. E. Wolff, Chem. Rev. 63, 55 (1963); E. J. Corey, W. R. Hertler, J. Am. Chem. Soc. 82, 1657 (1960); R. Furstoss et al., Tetrahedron Letters 1970, 1263; S. Titouani et al., Tetrahedron 36, 2961 (1980).

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Hofmann-Martius Rearrangement (Aniline Rearrangement) I Reaction & Chemical Reaction

A. W. Hofmann, C. A. Martius, Ber. 4, 742 (1871); A. W. Hofmann, ibid. 5, 720 (1872).

Thermal conversion of N-alkylaniline hydrohalides to o- and p-alkylanilines:

Hofmann-Martius Rearrangement (Aniline Rearrangement)

H. Hart, J. R. Kosak, J. Org. Chem. 27, 116 (1962); Y. Ogata et al., Tetrahedron 20, 2717 (1964); J. Org. Chem. 35, 1642 (1970); G. F. Grillot in Mechanisms of Molecular Migration vol. 3, B. S. Thyagarajan, Ed. (Wiley, New York, 1971) p 237; A. G. Giumanini et al., J. Org. Chem. 40, 1677 (1975); W. F. Burgoyne, D. D. Dixon, J. Mol. Catal. 62, 61 (1990); M. G. Siskos et al., Bull. Soc. Chim. Belg. 105, 759 (1996).

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Hofmann Degradation (Exhaustive Methylation) I Reaction & Chemical Reaction

A. W. Hofmann, Ber. 14, 659 (1881).

Formation of an olefin and a tertiary amine by pyrolysis of a quaternary ammonium hydroxide:

Hofmann Degradation (Exhaustive Methylation)

A. C. Cope, E. R. Trumbull, Org. React. 11, 317-493 passim (1960); K. W. Bentley, G. W. Kirby in Techniques of Organic Chemistry vol. IV, Pt. 2, A. Weissberger, Ed., Elucidation of Organic Structures by Physical and Chemical Methods (Wiley, New York, 2nd ed., 1973) pp 255-289. Isotope effects: R. D. Bach, M. L. Braden, J. Org. Chem. 56, 7194 (1991). Synthetic applications: A. D. Woolhouse et al., J. Heterocyclic Chem. 30, 873 (1993); D. Berkes et al., Synth. Commun. 28, 949 (1998). Cf. Cope Elimination Reaction; Emde Degradation.

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Hofmann Isonitrile Synthesis (Carbylamine Reaction) I Reaction & Chemical Reaction

A. W. Hofmann, Ann. 146, 107 (1868); Ber. 3, 767 (1870).

Formation of isonitriles by the reaction of primary amines with chloroform in the presence of alkali; the odor of the isocyanide is a test for a primary amine:

Hofmann Isonitrile Synthesis (Carbylamine Reaction)
P. A. S. Smith, N. W. Kalenda, J. Org. Chem. 23, 1599 (1958); M. B. Frankel et al., Tetrahedron Letters 1959, 5; H. L. Jackson, B. C. McKusick, Org. Syn. coll. vol. IV, 438 (1963); W. P. Weber, G. W. Gokel, Tetrahedron Letters 1972, 1637.

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Hofmann Reaction I carboxylic amides I hydroxide I Reaction & Chemical Reaction

A. W. Hofmann, Ber. 14, 2725 (1881).

Conversion of primary carboxylic amides to primary amines with one fewer carbon atom upon treatment with hypohalites or hydroxide via the intermediate isocyanate:

Hofmann Reaction

Early review: E. S. Wallis, J. F. Lane, Org. React. 3, 267-306 (1949). Alternative reagents/strategies: S. Kajigaeshi et al., Chem. Letters 1989, 463; S. Jew et al., Arch. Pharm. Res. 15, 333 (1992); D. S. Rane, M. M. Sharma, J. Chem. Tech. Biotechnol. 59, 271 (1994); H. Moustafa et al., Tetrahedron 53, 625 (1997); Y. Matsumura et al., J. Chem. Soc. Perkin Trans. I 1999, 2057. Review: T. Shioiri, Comp. Org. Syn. 6, 800-806 (1991). Cf. Curtius Rearrangement; Lossen Rearrangement; Schmidt Reaction; Weerman Degradation.

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Hofmann-Löffler-Freytag Reaction I Reaction & Chemical Reaction

A. W. Hofmann, Ber. 16, 558 (1883); 18, 5, 109 (1885); K. Löffler, C. Freytag, ibid. 42, 3427 (1909).

Formation of pyrrolidines or piperidines by thermal or photochemical decomposition of protonated N-haloamines:

Hofmann-Löffler-Freytag Reaction

M. E. Wolff, Chem. Rev. 63, 55 (1963); E. J. Corey, W. R. Hertler, J. Am. Chem. Soc. 82, 1657 (1960); R. Furstoss et al., Tetrahedron Letters 1970, 1263; S. Titouani et al., Tetrahedron 36, 2961 (1980).

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Hofmann-Martius Rearrangement (Aniline Rearrangement) Reaction & Chemical Reaction

A. W. Hofmann, C. A. Martius, Ber. 4, 742 (1871); A. W. Hofmann, ibid. 5, 720 (1872).

Thermal conversion of N-alkylaniline hydrohalides to o- and p-alkylanilines:
Hofmann-Martius Rearrangement (Aniline Rearrangement)
H. Hart, J. R. Kosak, J. Org. Chem. 27, 116 (1962); Y. Ogata et al., Tetrahedron 20, 2717 (1964); J. Org. Chem. 35, 1642 (1970); G. F. Grillot in Mechanisms of Molecular Migration vol. 3, B. S. Thyagarajan, Ed. (Wiley, New York, 1971) p 237; A. G. Giumanini et al., J. Org. Chem. 40, 1677 (1975); W. F. Burgoyne, D. D. Dixon, J. Mol. Catal. 62, 61 (1990); M. G. Siskos et al., Bull. Soc. Chim. Belg. 105, 759 (1996).

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Advantages I Asymmetric Synthesis of Epoxides and Aziridines from Aldehydes and Imines

Organic Synthesis & Epoxides and Aziridines
Epoxides and aziridines are strained three-membered heterocycles. Their synthetic utility lies in the fact that they can be ring-opened with a broad range of nucleophiles with high or often complete stereoselectivity and regioselectivity and that 1,2-difunctional ring-opened products represent common motifs in many organic

molecules of interest. As a result of their importance in synthesis, the preparation of epoxides and aziridines has been of considerable interest and many methods have been developed to date. Most use alkenes as precursors, these subsequently being oxidized. An alternative and complementary approach utilizes aldehydes
and imines. Advantages with this approach are: i) that potentially hazardous oxidizing agents are not required, and ii) that both C–X and C–C bonds are formed, rather than just C–X bonds

This review summarizes the best asymmetric methods for preparing epoxides nd aziridines from aldehydes (or ketones) and imines

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Asymmetric Epoxidation of Carbonyl Compounds I Darzens reaction

Organic Synthesis - Epoxides and Aziridines
There have been two general approaches to the direct asymmetric epoxidation of carbonyl-containing compounds (Scheme 1.2): ylide-mediated epoxidation for the construction of aryl and vinyl epoxides, and a-halo enolate epoxidation (Darzens reaction) for the construction of epoxy esters, acids, amides, and sulfones.

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Stoichiometric Ylide-mediated Epoxidation I asymmetric epoxidation I synthesized aryl-vinyl epoxides

Organic Synthesis & Epoxides and Aziridines
Solladié-Cavallo’s group used Eliel’s oxathiane 1 (derived from pulegone) in asymmetric epoxidation (Scheme 1.3). This sulfide was initially benzylated to form a single diastereomer of the sulfonium salt 2. Epoxidation was then carried out at low temperature with the aid of sodium hydride to furnish diaryl epoxides 3 with
high enantioselectivities, and with recovery of the chiral sulfide 1.

Using a phosphazene (EtP2) base, they also synthesized aryl-vinyl epoxides 6a-c Table 1.1). The use of this base resulted in rapid ylide formation and efficient poxidation reactions, although it is an expensive reagent. There is potential for yclopropanation of the alkene when sulfur ylides are treated with a,b-unsaturated
aldehydes, but the major products were the epoxides, and high selectivities could e achieved (Entries 1–4). Additionally, heteroaromatic aryl-epoxides could be prepared ith high selectivities by this procedure (Entries 5 and 6). Although high electivities have been achieved, it should be noted that only one of the two enantiomers f 1 is readily available.

The Aggarwal group has used chiral sulfide 7, derived from camphorsulfonyl hloride, in asymmetric epoxidation. Firstly, they preformed the salt 8 from ither the bromide or the alcohol, and then formed the ylide in the presence of a ange of carbonyl compounds. This process proved effective for the synthesis of aryl-aryl, aryl-heteroaryl, aryl-alkyl, and aryl-vinyl epoxides (Table 1.2, Entries 1 –5).

Until this work, the reactions between the benzyl sulfonium ylide and ketones to give trisubstituted epoxides had not previously been used in asymmetric sulfur lide-mediated epoxidation. It was found that good selectivities were obtained with yclic ketones (Entry 6), but lower diastereo- and enantioselectivities resulted with cyclic ketones (Entries 7 and 8), which still remain challenging substrates for sulfur ylide-mediated epoxidation. In addition they showed that aryl-vinyl epoxides sould also be synthesized with the aid of a,b-unsaturated sulfonium salts 10a-b (Scheme 1.4).

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Hofmann-Sand Reactions I alkoxyalkyl I Organometallic

Reaction & Chemical Reaction

K. A. Hofmann, J. Sand, Ber. 33, 1340, 1353 (1900).

Olefin mercuration with mercuric salts (halides, acetates, nitrates, or sulfates) in aqueous solution. In alcoholic solutions the accelerated reaction produces alkoxyalkyl compounds:

Hofmann-Sand Reactions
J. Sand, Ber. 34, 1385, 2906, 2910 (1901); Ann. 329, 135 (1903); J. Chatt, Chem. Rev. 48, 7 (1951); E. R. Rochow et al., Chemistry of Organometallic Compounds (New York, 1957) p 109; W. Kitching, Organomet. Chem. Rev. 3, 35 (1968); K. P. Geller, H. Straub, Houben-Weyl 13/2b, 130 (1974).

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Hooker Reaction I Steyermark I hydroxy I methylene

Reaction & Chemical Reaction

S. C. Hooker, J. Am. Chem. Soc. 58, 1174 (1936).

Oxidation of 2-hydroxy-3-alkyl-1,4-quinones with dilute alkaline permanganate with shortening of the alkyl side chain by a methylene group and simultaneous exchange of hydroxyl and alkyl or alkenyl group positions:
Hooker Reaction
S. C. Hooker, A. Steyermark, J. Am. Chem. Soc. 58, 1179 (1936); L. F. Fieser, M. Fieser, ibid. 70, 3215 (1948); L. F. Fieser, A. R. Bader, ibid. 73, 681 (1951); L. F. Fieser, M. Fieser, Advanced Organic Chemistry (New York, 1961) p 870.

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Synthetic applications I Sakurai Reaction (Hosomi-Sakurai Reaction) Organometallic

Reaction & Chemical Reaction:
A. Hosomi, H. Sakurai, Tetrahedron Letters 1976, 1295; A. Hosomi et al., Chem. Letters 1976, 941.

Lewis acid-promoted nucleophilic addition of allylic silanes to carbon electrophiles accompanied by regiospecific transposition of the allylic moiety:
Sakurai Reaction (Hosomi-Sakurai Reaction)

Synthetic applications: I. E. Markó, D. J. Bayston, Tetrahedron Letters 34, 6595 (1993); H. Hioki et al., ibid. 6131. [TiCp2(OSO2CF3)2] as catalyst: T. K. Hollis et al., ibid. 4309. Reviews: I. Fleming et al., Org. React. 37, 57-575 (1989); Y. Yamamoto, N. Sasaki, “The Stereochemistry of the Sakurai Reaction” in Stereochemistry of Organometallic and Inorganic Compounds vol. 3, I. Bernal, Ed. (Elsevier, New York, 1989) pp 363-437; I. Fleming, Comp. Org. Syn. 2, 563-593 (1991).

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Acidic hydrolysis yields ketones - Houben-Fischer Synthesis

Reaction & Chemical Reaction

J. Houben, W. Fischer, J. Prakt. Chem. [2] 123, 89, 262, 313 (1929).

Formation of aromatic nitriles by basic hydrolysis of trichloromethyl aryl ketimines. Acidic hydrolysis yields ketones.

J. Houben, W. Fischer, Ber. 63, 2464 (1930); 64, 240, 2636, 2645 (1931); 66, 339 (1933); D. T. Mowry, Chem. Rev. 42, 221 (1948); P. E. Spoerri, A. S. DuBois, Org. React. 5, 390 (1949); G. Hesse, Houben-Weyl 4/2 103 (1955); W. Ruske in Friedel-Crafts and Related Reactions vol. III, Part 1, G. A. Olah, Ed. (Interscience, New York, 1964) p 407. Cf. Houben-Hoesch Reaction.

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Acylphenols - Houben-Hoesch Reaction - Chemistry

Reaction & Chemical Reaction

K. Hoesch, Ber. 48, 1122 (1915); J. Houben, ibid. 59, 2878 (1926).

Synthesis of acylphenols from phenols or phenolic ethers by the action of organic nitriles in the presence of hydrochloric acid and aluminum chloride as catalyst:


Houben-Hoesch Reaction

Reviews: P. E. Spoerri, A. S. DuBois, Org. React. 5, 387 (1949); Thomas, Anhydrous Aluminum Chloride in Organic Chemistry (New York, 1941) p 504; W. Ruske in Friedel-Crafts and Related Reactions vol. III, Part 1, G. A. Olah, Ed. (Interscience, New York, 1964) p 383; M. I. Amer et al., J. Chem. Soc. Perkin Trans. I 1983, 1075; V. V. Arkhipov et al., Chem. Heterocycl. Compd. 33, 515 (1997); R. Kawecki et al., Synthesis 1999, 751. Cf. Gatterman Aldehyde Synthesis; Houben-Fischer Synthesis.

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Chemical Technology I Houdry Cracking Process

oxide - Reaction - Chemical Reaction
Houdry. Houdry Cracking ProcessE. Houdry, US 1957648 and US 1957649 (1934).

Decomposition of petroleum or heavy petroleum fractions into more useful lower boiling materials by heating at 500° and 30 psi, over a silica-alumina-magnanese oxide catalyst.

E. Houdry et al., Oil Gas J. 37, 40 (1938); A. N. Sachanen, Chemical Constituents of Petroleum (New York, 1945) p 260; V. Haensel, M. J. Sterba, Ind. Eng. Chem. 40, 1662 (1948); Kirk-Othmer Encyclopedia of Chemical Technology 4, 323, 357 (New York, 1979); E. Boye, Chemiker-Ztg. 81, 341 (1957); S. Gussow et al., Oil Gas J. 78, 96 (1980); C. G. Mosley, J. Chem. Ed. 61, 655 (1984); G. A. Mills, Chemtech 1986, 72; Y. Nishimura, Petrotech 21, 605 (1998).

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stereoselectivity I Asymmetric Synthesis of Epoxides and Aziridines from Aldehydes and Imines

Organic Synthesis & Epoxides and Aziridines:
Epoxides and aziridines are strained three-membered heterocycles. Their synthetic utility lies in the fact that they can be ring-opened with a broad range of nucleophiles with high or often complete stereoselectivity and regioselectivity and that 1,2-difunctional ring-opened products represent common motifs in many organic

molecules of interest. As a result of their importance in synthesis, the preparation of epoxides and aziridines has been of considerable interest and many methods have been developed to date. Most use alkenes as precursors, these subsequently being oxidized. An alternative and complementary approach utilizes aldehydes
and imines. Advantages with this approach are: i) that potentially hazardous oxidizing agents are not required, and ii) that both C–X and C–C bonds are formed, rather than just C–X bonds

This review summarizes the best asymmetric methods for preparing epoxides nd aziridines from aldehydes (or ketones) and imines

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Darzens reaction I Asymmetric Epoxidation of Carbonyl Compounds

Organic Synthesis & Epoxides and Aziridines:

There have been two general approaches to the direct asymmetric epoxidation of carbonyl-containing compounds (Scheme 1.2): ylide-mediated epoxidation for the construction of aryl and vinyl epoxides, and a-halo enolate epoxidation (Darzens reaction) for the construction of epoxy esters, acids, amides, and sulfones.

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Asymmetric epoxidation I Stoichiometric Ylide-mediated Epoxidation

Camphorsulfonyl hloride - Organic Synthesis - Epoxides and Aziridines :

Solladié-Cavallo’s group used Eliel’s oxathiane 1 (derived from pulegone) in asymmetric epoxidation (Scheme 1.3). This sulfide was initially benzylated to form a single diastereomer of the sulfonium salt 2. Epoxidation was then carried out at low temperature with the aid of sodium hydride to furnish diaryl epoxides 3 with
high enantioselectivities, and with recovery of the chiral sulfide 1.

Using a phosphazene (EtP2) base, they also synthesized aryl-vinyl epoxides 6a-c Table 1.1). The use of this base resulted in rapid ylide formation and efficient poxidation reactions, although it is an expensive reagent. There is potential for yclopropanation of the alkene when sulfur ylides are treated with a,b-unsaturated
aldehydes, but the major products were the epoxides, and high selectivities could e achieved (Entries 1–4). Additionally, heteroaromatic aryl-epoxides could be prepared ith high selectivities by this procedure (Entries 5 and 6). Although high electivities have been achieved, it should be noted that only one of the two enantiomers f 1 is readily available.

The Aggarwal group has used chiral sulfide 7, derived from camphorsulfonyl hloride, in asymmetric epoxidation. Firstly, they preformed the salt 8 from ither the bromide or the alcohol, and then formed the ylide in the presence of a ange of carbonyl compounds. This process proved effective for the synthesis of aryl-aryl, aryl-heteroaryl, aryl-alkyl, and aryl-vinyl epoxides (Table 1.2, Entries 1 –5).

Until this work, the reactions between the benzyl sulfonium ylide and ketones to give trisubstituted epoxides had not previously been used in asymmetric sulfur lide-mediated epoxidation. It was found that good selectivities were obtained with yclic ketones (Entry 6), but lower diastereo- and enantioselectivities resulted with cyclic ketones (Entries 7 and 8), which still remain challenging substrates for sulfur ylide-mediated epoxidation. In addition they showed that aryl-vinyl epoxides sould also be synthesized with the aid of a,b-unsaturated sulfonium salts 10a-b (Scheme 1.4).

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Alkoxyalkyl I Hofmann-Sand Reactions, alkoxyalkyl

Organometallic Compounds
K. A. Hofmann, J. Sand, Ber. 33, 1340, 1353 (1900).

Olefin mercuration with mercuric salts (halides, acetates, nitrates, or sulfates) in aqueous solution. In alcoholic solutions the accelerated reaction produces alkoxyalkyl compounds:

Hofmann-Sand Reactions

J. Sand, Ber. 34, 1385, 2906, 2910 (1901); Ann. 329, 135 (1903); J. Chatt, Chem. Rev. 48, 7 (1951); E. R. Rochow et al., Chemistry of Organometallic Compounds (New York, 1957) p 109; W. Kitching, Organomet. Chem. Rev. 3, 35 (1968); K. P. Geller, H. Straub, Houben-Weyl 13/2b, 130 (1974).

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Chemical Reaction, Hooker Reaction, hydroxy, alkyl

Oxidation of
S. C. Hooker, J. Am. Chem. Soc. 58, 1174 (1936).

Oxidation of 2-hydroxy-3-alkyl-1,4-quinones with dilute alkaline permanganate with shortening of the alkyl side chain by a methylene group and simultaneous exchange of hydroxyl and alkyl or alkenyl group positions:
Hooker Reaction
S. C. Hooker, A. Steyermark, J. Am. Chem. Soc. 58, 1179 (1936); L. F. Fieser, M. Fieser, ibid. 70, 3215 (1948); L. F. Fieser, A. R. Bader, ibid. 73, 681 (1951); L. F. Fieser, M. Fieser, Advanced Organic Chemistry (New York, 1961) p 870.

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Wittig Reaction; Horner Reaction; Horner-Wadsworth-Emmons Reaction - phosphonium ylides

G. Wittig, U. Schöllkopf, Ber. 87, 1318 (1954); G. Wittig, W. Haag, ibid. 88, 1654 (1955).

Alkene formation from carbonyl compounds and phosphonium ylides, proceeding primarily through the proposed betaine and/or oxaphosphetane intermediates. The stereoselectivity can be controlled by the choice of ylide, carbonyl compound, and reaction conditions:
Wittig Reaction; Horner Reaction; Horner-Wadsworth-Emmons Reaction
When the ylide is replaced with a phosphine oxide carbanion, the reaction is referred to as the Horner reaction: L. Horner et al., Ber. 91, 61 (1958); idem et al., ibid. 92, 2499 (1959).

When the ylide is replaced with a phosphonate carbanion, the reaction is referred to as the Horner-Emmons-Wadsworth reaction: W. S. Wadsworth, Jr., W. D. Emmons, J. Am. Chem. Soc. 83, 1733 (1961).

Application to the synthesis of ß,?-unsaturated amides: T. Janecki et al., Tetrahedron 51, 1721 (1995). Reviews: A. Maercker, Org. React. 14, 270-490 (1965); K. P. C. Vollhardt, Synthesis 1975, 765-780; W. S. Wadsworth, Jr., Org. React. 25, 73-253 (1977); I. Gosney, A. G. Rowley in Organophosphorus Reagents in Organic Synthesis, J. I. G. Cadogan, Ed. (Academic Press, New York, 1979) pp 17-153; B. E. Maryanoff, A. B. Reitz, Chem. Rev. 89, 863-927 (1989); S. E. Kelly, Comp. Org. Syn. 1, 755-782 (1991). Reviews of mechanistic studies: W. E. McEwen et al., ACS Symposium Series 486, 149-161 (1992); E. Vedejs, M. J. Peterson, Top. Stereochem. 21, 1-157 (1994). Cf. Peterson Reaction; Tebbe Reaction.

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Sakurai Reaction (Hosomi-Sakurai Reaction), regiospecific transposition

A. Hosomi, H. Sakurai, Tetrahedron Letters 1976, 1295; A. Hosomi et al., Chem. Letters 1976, 941.

Lewis acid-promoted nucleophilic addition of allylic silanes to carbon electrophiles accompanied by regiospecific transposition of the allylic moiety:
Sakurai Reaction (Hosomi-Sakurai Reaction)


Synthetic applications: I. E. Markó, D. J. Bayston, Tetrahedron Letters 34, 6595 (1993); H. Hioki et al., ibid. 6131. [TiCp2(OSO2CF3)2] as catalyst: T. K. Hollis et al., ibid. 4309. Reviews: I. Fleming et al., Org. React. 37, 57-575 (1989); Y. Yamamoto, N. Sasaki, “The Stereochemistry of the Sakurai Reaction” in Stereochemistry of Organometallic and Inorganic Compounds vol. 3, I. Bernal, Ed. (Elsevier, New York, 1989) pp 363-437; I. Fleming, Comp. Org. Syn. 2, 563-593 (1991).

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Sakurai Reaction (Hosomi-Sakurai Reaction), regiospecific transposition

A. Hosomi, H. Sakurai, Tetrahedron Letters 1976, 1295; A. Hosomi et al., Chem. Letters 1976, 941.

Lewis acid-promoted nucleophilic addition of allylic silanes to carbon electrophiles accompanied by regiospecific transposition of the allylic moiety:
Sakurai Reaction (Hosomi-Sakurai Reaction)


Synthetic applications: I. E. Markó, D. J. Bayston, Tetrahedron Letters 34, 6595 (1993); H. Hioki et al., ibid. 6131. [TiCp2(OSO2CF3)2] as catalyst: T. K. Hollis et al., ibid. 4309. Reviews: I. Fleming et al., Org. React. 37, 57-575 (1989); Y. Yamamoto, N. Sasaki, “The Stereochemistry of the Sakurai Reaction” in Stereochemistry of Organometallic and Inorganic Compounds vol. 3, I. Bernal, Ed. (Elsevier, New York, 1989) pp 363-437; I. Fleming, Comp. Org. Syn. 2, 563-593 (1991).

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Houben-Fischer Synthesis I Acidic hydrolysis yields ketones

J. Houben, W. Fischer, J. Prakt. Chem. [2] 123, 89, 262, 313 (1929).

Formation of aromatic nitriles by basic hydrolysis of trichloromethyl aryl ketimines. Acidic hydrolysis yields ketones.

J. Houben, W. Fischer, Ber. 63, 2464 (1930); 64, 240, 2636, 2645 (1931); 66, 339 (1933); D. T. Mowry, Chem. Rev. 42, 221 (1948); P. E. Spoerri, A. S. DuBois, Org. React. 5, 390 (1949); G. Hesse, Houben-Weyl 4/2 103 (1955); W. Ruske in Friedel-Crafts and Related Reactions vol. III, Part 1, G. A. Olah, Ed. (Interscience, New York, 1964) p 407. Cf. Houben-Hoesch Reaction.
Houben-Fischer Synthesis

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Houben-Hoesch Reaction, Synthesis of acylphenols

K. Hoesch, Ber. 48, 1122 (1915); J. Houben, ibid. 59, 2878 (1926).

Synthesis of acylphenols from phenols or phenolic ethers by the action of organic nitriles in the presence of hydrochloric acid and aluminum chloride as catalyst:

Houben-Hoesch Reaction

Reviews: P. E. Spoerri, A. S. DuBois, Org. React. 5, 387 (1949); Thomas, Anhydrous Aluminum Chloride in Organic Chemistry (New York, 1941) p 504; W. Ruske in Friedel-Crafts and Related Reactions vol. III, Part 1, G. A. Olah, Ed. (Interscience, New York, 1964) p 383; M. I. Amer et al., J. Chem. Soc. Perkin Trans. I 1983, 1075; V. V. Arkhipov et al., Chem. Heterocycl. Compd. 33, 515 (1997); R. Kawecki et al., Synthesis 1999, 751. Cf. Gatterman Aldehyde Synthesis; Houben-Fischer Synthesis.

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Houdry Cracking Process, Houdry, oxide catalyst

Houdry Cracking ProcessE. Houdry, US 1957648 and US 1957649 (1934).

Decomposition of petroleum or heavy petroleum fractions into more useful lower boiling materials by heating at 500° and 30 psi, over a silica-alumina-magnanese oxide catalyst.

E. Houdry et al., Oil Gas J. 37, 40 (1938); A. N. Sachanen, Chemical Constituents of Petroleum (New York, 1945) p 260; V. Haensel, M. J. Sterba, Ind. Eng. Chem. 40, 1662 (1948); Kirk-Othmer Encyclopedia of Chemical Technology 4, 323, 357 (New York, 1979); E. Boye, Chemiker-Ztg. 81, 341 (1957); S. Gussow et al., Oil Gas J. 78, 96 (1980); C. G. Mosley, J. Chem. Ed. 61, 655 (1984); G. A. Mills, Chemtech 1986, 72; Y. Nishimura, Petrotech 21, 605 (1998).

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Carbonyl, Wolff-Kishner Reduction; Huang-Minlon Modification "methyl"

N. Kishner, J. Russ. Phys. Chem. Soc. 43, 582 (1911), C.A. 6, 347 (1912); L. Wolff, Ann. 394, 86 (1912); Huang-Minlon, J. Am. Chem. Soc. 68, 2487 (1946).

Complete reduction of carbonyl compounds to methyl or methylene groups on heating with hydrazine hydrate and a base. In the Huang-Minlon modification diethylene glycol is used as a solvent:
Wolff-Kishner Reduction; Huang-Minlon Modification


Reviews: D. Todd, Org. React. 4, 378 (1948); H. H. Szmant, Angew. Chem. Int. Ed. 7, 120 (1968); F. Asinger, H. H. Vogel, Houben-Weyl 5/1a, 251, 456 (1970); H. Balli, ibid. 5/1b, 629 (1972); R. O. Hutchins, M. K. Hutchins, Comp. Org. Syn. 8, 327-343 (1991). Bond cleavage: R. P. Lemieux, P. Beak, Tetrahedron Letters 30, 1353 (1989). Synthetic application: A. Srikrishna, D. Vijaykumuv, J. Chem. Soc. Perkin Trans. I 1999, 1265. Cf. Clemmensen Reduction; Haworth Phenanthrene Synthesis.

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Chemical, Pictet-Hubert Reaction Morgan-Walls Reaction, Morgan-Walls Reaction

A. Pictet, A. Hubert, Ber. 29, 1182 (1896); C. T. Morgan, L. P. Walls, J. Chem. Soc. 1931, 2447; 1932, 2225.

Phenanthridine cyclization by dehydrative ring closure of acyl-o-aminobiphenyls on heating with zinc chloride at 250-300° (Pictet-Hubert), or with phosphorus oxychloride in boiling nitrobenzene (Morgan-Walls):


Pictet-Hubert Reaction; Morgan-Walls Reaction


L. P. Walls, J. Chem. Soc. 1945, 294; J. Cymerman, W. F. Short, ibid. 1949, 703; R. S. Theobald, K. Schofield, Chem. Rev. 46, 175 (1950); L. P. Walls, Heterocyclic Compounds 4, 574 (1952); J. Eisch, H. Gilman, Chem. Rev. 57, 525 (1957); N. Campbell, Chemistry of Carbon Compounds IVA, 691 (1957). Cf. Bischler Napieralski Reaction.

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Hunsdiecker Reaction (Borodine Reaction), catalysis, Hunsdiecker, decarboxylation

Chowdhury, decarboxylation
C. Hunsdiecker et al., US 2176181 (1939); H. Hunsdiecker, C. Hunsdiecker, Ber. 75, 291 (1942); A. Borodine, Ann. 119, 121 (1861).

Synthesis of organic halides by thermal decarboxylation of silver salts of the corresponding carboxylic acids in the presence of halogens
Hunsdiecker Reaction (Borodine Reaction)

R. G. Johnson, R. K. Ingham, Chem. Rev. 56, 219 (1956); C. V. Wilson, Org. React. 9, 341 (1957); S. J. Cristol, W. C. Firth, Jr., J. Org. Chem. 26, 280 (1961); F. F. Knapp, Jr., Steroids 33, 245 (1979); A. I. Meyers, M. P. Fleming, J. Org. Chem. 44, 3405 (1979). Modified catalysis by metal salt pool: S. Chowdhury, S. Roy, Tetrahedron Letters 37, 2623 (1996); D. Naskar, S. Roy, J. Chem. Soc. Perkin Trans. I 1999, 2436; eidem, Tetrahedron 56, 1369 (2000). Cf. Kochi Reaction; Simonini Reaction. Hunsdiecker Reaction (Borodine Reaction)

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Hydroboration Reaction, hydrides, organoboranes, alkynes

Ohlmeyer, Adv. Chem, Suzuki Coupling, asymmetric
H. C. Brown, B. C. Subba Rao, J. Am. Chem. Soc. 78, 5694 (1956); J. Org. Chem. 22, 1135, 1136 (1957).

Addition of boron hydrides to alkenes, allenes, and alkynes to form organoboranes, such that boron adds to the less substituted carbon. Attack usually takes place on the less hindered side in a cis fashion:
Hydroboration Reaction


Diastereofacial and regioselectivity study: B. W. Gung et al., Synth. Commun. 24, 167 (1994). Methods development for asymmetric synthesis: U. P. Dhokte, H. C. Brown, Tetrahedron Letters 35, 4715 (1994). Application to hydration: G. Zweifel, H. C. Brown, Org. React. 13, 1-54 (1963). General reviews: H. O. House, Modern Synthetic Reactions (W. A. Benjamin, Menlo Park, California, 2nd ed., 1972) pp 106-130; K. Smith, A. Pelter, Comp. Org. Syn. 8, 703-731 (1991). Reviews of asymmetric synthesis: H. C. Brown, Tetrahedron 37, 3547-3587 (1981); K. Burgess, M. J. Ohlmeyer, Adv. Chem. Ser. 230, 163-177 (1992). Cf. Suzuki Coupling.

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Oxo Process (Hydroformylation Reaction), The process is sometimes carried out in two stages

Hydroformylation. Oxo Synthesis, Roelen Reaction
O. Roelen, US 2327066 (1943); R. H. Hasek (Eastman), Org. Chem. Bull. 27, No. 1 (1955).

Formation of alcohols from olefins, carbon monoxide and hydrogen in the liquid phase in the presence of catalysts (metallic cobalt compounds such as Raney cobalt or cobalt carbonyls) at 115-190° and high pressures (100-200 atmospheres) in a Fischer-Tropsch-type reaction, q.v. The process is sometimes carried out in two stages, the initial stage giving largely aldehydes which are then reduced to the alcohols.

B. Cornils, “Hydroformylation. Oxo Synthesis, Roelen Reaction” in New Syntheses with Carbon Monoxide, J. Falbe, Ed. (Springer-Verlag, Berlin, 1980) pp 1-225. Reppe modification (olefin + CO + H2O + Fe(CO)5): R. Massoudi et al., J. Am. Chem. Soc. 109, 7428 (1987).

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Focused ultrasound ablation, Skin burns, Back or leg pain, Nerve damage, Abdominal pain, Cramping, Nausea, Fever, Vaginal discharge, Urinary tract inf

KK Women's and Children's Hospital is now equipped with the new MR-guided Focused Ultrasound Ablation System, offering a non-invasive, effective and outpatient solution to treat uterine fibroids.

The system, ExAblate 2000, has been highlighted by U.S. FDA as one of the 14 medically significant products it approved during fiscal 2005.

What are Uterine Fibroids?

Fibroids are benign (non-cancerous) tumours most often found in the uterus. They are the most common gynaecological tumour in women and exist in various types. Approximately 20-40% of women aged more than 35 years old have fibroids

Uterine fibroids can affect your quality of life

They can cause

* Cramps
* Abdominal pain
* Heavy menstrual bleeding
* Frequent urination
* Constipation
* Distended stomach

Until now, most treatment options are invasive surgical procedures such as hysterectomy (removal of uterus) or myomectomy (removal of the fibroids).

Alxia and coronal views of the pelvis showing uterine fibroid

MR-guided Focused Ultrasound Ablation:
A Non-Invasive Treatment Alternative

MR-guided Focused Ultrasound Ablation provides a non-invasive treatment alternative for fibroids. It treats Uterine Fibroids without the need for incisions, anaesthesia and hospitalisation.

High intensity focused ultrasound waves are used to heat an area of the fibroid, causing cell death. Pulses of ultrasound energy are repeatedly applied to treat the fibroid.
During treatment, magnetic resonance images are used to enable the doctor to see the fibroid and surrounding organs in 3-D, pinpoint, guide, and continuously monitor the treatment in a non-invasive manner.

Before treatment: View of the uterine fibroids,
without contrast (left picture) and with contrast (right picture)

View of the treated fibroids Preparation for Ultrasound Ablation

As this treatment requires MR imaging, you are required to have a pre–treatment MR scan of your pelvis with an intravenous injection of contrast to assess whether you are suitable for the ablation treatment.

You must also complete a MR safety questionnaire to assess that it is safe to perform the MR scan on you.

Post-treatment scans will also be done a few months later to ascertain the progress of the treatment.
What happens during the procedure?

During the 3-4 hour procedure, you will be required to lie on your stomach. Sedation and pain relieving medication will be given to help you relax. You will be conscious throughout the procedure. You will feel some warm sensation over the abdomen during the treatment. This is a normal occurrence.

The doctor obtains MR images of your uterus and uses these to plan your treatment. Individual pulses of focused ultrasound energy each lasting about 20 seconds will be applied to your fibroids.

Thereafter, MR images are taken to evaluate treatment effectiveness

What happens to me after MR-Guided Focused Ultrasound Ablation?

After the procedure, you need to rest for 1-2 hours for the sedation to wear off. You may experience some abdominal pain, cramping or nausea. If necessary, your doctor will provide instructions for medication to keep you comfortable upon discharge. You may experience some cramps, shoulder or back pain that may last a few days after the procedure. Most women are able to return to work within 1-2 days.

What are the risks of MR-Guided Ultrasound Ablation?

Like any medical procedure, there are risks involved. The incidence of these complications is very low. These complications include:

* Skin burns
* Back or leg pain
* Nerve damage
* Abdominal pain
* Cramping
* Nausea
* Fever
* Vaginal discharge
* Urinary tract infection
* Alternative treatment required if treatment is not successful
* Recurrence of fibroids in the future

How do I know if I'm a candidate for MR guided Focused ultrasound ablation?

Your doctor will be able to assess your suitability for the procedure. Thereafter, a referral can be made to KK Women’s and Children’s Hospital.

Please note that this procedure is meant for women who do not wish to become pregnant in the future. The effects of the procedure on the ability to conceive and to carry a foetus to term have yet to be determined.

Click here for Frequently Asked Questions (FAQs) - Updated 1 July 2007

If you have any further queries or need to talk to a Diagnostic Imaging resource person on this
MR-guided Focused Ultrasound Ablation service, please
email to ablate.fibroids@kkh.com.sg or
call (65) 9736 2250 (hand-phone) during office hours.

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Medical Specialties & Service Center I Men I Women's Center, I pain urinary endometriosis menopause I hurt

Women's Pain Center
Help for women to overcome the pain

Location Level 1 (in KK Breast Center)
Phone 6294 4050 (for appointments)
6394 8073 (for questions)
E-mail womenpaincentre@kkh.com.sg

Do not suffer in silence. We can take your pain, so you can enjoy life again.

Their pain twice a month cycle of menstrual cramps? Or you dying with the pain of arthritis, Migraines, herniated discs, or you're sick of it and not able to display the day-to-day activities?

Here in the Women's Pain Center, we can treat pain and facilitate you with the latest technology that does not require you to go with the knife.

Our Women's Pain Center is one of the first in Germany to use laser technology software that is used to cause cells to treat injuries such as muscle sprains, tears in the ligaments and tendons. Because the non-invasive, recovery time can be more quickly - in a matter of days, not weeks.

Centers also use laser-injection procedure with minimal invasion by desensitization to the pain affected nerves. If necessary, you may be oral prescription medication and physiotherapy, so that pain is better.

During the consultation, the doctor will diagnose your condition and source of pain. Then he will, if necessary, with the physiotherapist on the individual short-term and long-term planning to meet your needs. If your doctor thinks that you can benefit from some counseling to strengthen and motivate you to overcome the pain, he will direct you to a psychologist.

Some conditions, we are:
• pelvic pain (pain in the abdominal area)
• Arthritis
• musculo-frame conditions (together, back and neck pain)
• Sports Injuries
• pain from damaged nerve
• Cancer pain

Persistent pain after surgery
• menstrual pain
• Herniated discs
• shingles
• Migraine

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Medical Specialties & Services I Children's Hospital I Medical I Respiratory Medicine I Partners in Asthma Care I Druckansicht Druckversion

KKH Partners in Asthma Care

Service of respiratory medicine KK Women's and Children's Hospital shortly KKH Partners in Asthma Care - a program for community and primary health care KKH specialists work together as a team and manage child asthma conditions.

Under this program, children with asthma are relatively stable, are becoming the family doctor and children's doctors to integrated care, while maintaining the KKH specialist akan regular review and patient interaction, to optimize the treatment.

Recruitment of community partners will start with 6 Update in Pediatric Practice, 2008, on 23 August. A segment with the title "Children in asthma - An Update", by Dr. Jenny Tang, Head & Senior Consultant, respiratory medicine service will look at the criteria, modalities and the management of the program.

We invite you to a partner in KKH Asthma Care if:

* You are a GP Practice or Pediatrician
They include the practice of evidence-based care in line with the practice guidelines
* You want to participate in regular CME programs KKH
* You agree to two-way exchange of information on integrated medical care patients

KKH as a partner in the Asthma Care you will be entitled to various benefits, such as:

* Access to care of the respiratory tract specialists and nurses from KKH
* Fast-track dates for the integrated patient care
* Automatic enrollment SingHealth Empowerment Program General Practitioners (GPEP) with privileges
* Direct access to patient's membership SingHealth GPEP rights
* Continuation of the patients included in the asthma club (in support of the patient group) for at least two years after the treatment under
* As a specialist recommended by KKH to the steps under our care bronchial asthma patients
KKH CME * Priority registration for programs
* Priority access to the lung function laboratory (in 2009)

If you are interested in our affiliate program, please indicate your interest by
Fax to 63941973 or by e-mail with the information necessary for AsthmaComCare@kkh.com.sg.

For more information on the KKH Partners in Asthma Care, you can use the Community Asthma Care Nurse in 63948595, to write in AsthmaComCare@kkh.com.sg, 63941973 or fax.

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