Switchable Reactivity of Acylated α, β-Dehydroamino Ester in the Friedel−Crafts Alkylation of Indoles by Changing the Lewis Acid

Abstract

Highly regioselective electrophilic substitution of indoles with N-acetylated alpha,beta-dehydroalanine methyl ester, promoted by different transition metal salts was achieved. The orthogonal regioselectivity provides an efficient protocol toward highly functionalized 3-indolyl-alpha-amino acids. The mechanism of the reactions was explored by NMR studies.