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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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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