An Efficient Synthetic Method to Nonnatural α‐ and β‐Tryptophan Analogues via Friedel‐Crafts Alkylation of Indoles with Nitroacrylates

Abstract

AbstractThe Friedel‐Crafts alkylation of indoles with nitroacrylates could provide α‐ and β‐tryptophan nitro‐precursors, respectively, in moderate to good yields under Lewis acid catalysis. The diastereoselectivities of the reaction were enhanced by using 2‐substituted indoles. The alkylation products could be easily transformed to nonnatural tryptophan derivatives.