Access to C5-Alkylated Indolines/Indoles via Michael-Type Friedel-Crafts Alkylation Using Aryl-Nitroolefins.

A straightforward synthetic route toward C5-alkylated indolines/indoles has been developed. The strategy is composed of Zn(OTf)-catalyzed Friedel-Crafts alkylation of N-benzylindolines with nitroolefins, and a series of diverse indolines was first obtained in up to 99% yield. This reaction provides a direct and practical route to a variety of the C5-alkylated indolines which were also utilized for accessing corresponding indoles.