Regioselective Fischer indole synthesis mediated by organoaluminum amides

Article abstract of DOI:10.1021/jo00079a005

Amphiphilic reagents such as organoaluminum amides are found to be highly effective for the Fischer indole synthesis. In particular, diethylaluminum 2,2,6,6-tetramethylpiperidide (DATMP) is the reagent of choice for regioselective Fischer indole synthesis. For example, treatment of the (E)- N-methyl-N-phenylhydrazone of 5-methyl-3-heptanone with DATMP affords 3-sec- butyl-2-ethyl-1-methylindole as the sole isolable product; its Z-isomer affords 1,3-dimethyl-2-(2-methylbutyl)indole with high regioselectivity under similar reaction conditions.