1995 年 43 巻 8 号 p. 1287-1293
In connection with studies on the direction of cyclization in the Fischer indolization of substituted diphenylhydrazones, the Fischer indolization of ethyl pyruvate 2-bis(2-methoxyphenyl)hydrazone (6) was carried out. The result showed that cyclization in Fischer indolization of diphenylhydrazone does not always proceed to the electron-richer nucleus, but depends on the conformation of the enehydrazine. Thus, the Fischer indolization should proceed via a [3, 3] sigmatropic route, with an electronic effect.