Fischer Synthesis

E. Fischer, F. Jourdan, Ber. 16, 2241 (1883); E. Fischer, O. Hess, ibid. 17, 559 (1884).

Formation of indoles on heating aryl hydrazones of aldehydes or ketones in the presence of catalysts such as Lewis or proton acids:



Reviews: B. Robinson, Chem. Rev. 63, 373 (1963); 69, 227 (1969); H. Ishii, Accts. Chem. Res. 14, 233-247 (1981); B. Robinson, The Fischer Indole Synthesis (Wiley, New York, 1982) 923 pp.; D. L. Hughes, Org. Prep. Proced. Int. 25, 607-632 (1993). Modified conditions: S. M. Hutchins, K. T. Chapman, Tetrahedron Letters 37, 4869 (1996); O. Miyata et al., ibid. 40, 3601 (1999); S. Wagaw et al., J. Am. Chem. Soc. 121, 10251 (1999). Cf. Borsche-Drechsel Cyclization; Piloty-Robinson Synthesis.