Chiral vicinal diamines as promising ligands in Pd-catalyzed reductive Heck type cyclizations

Abstract

Palladium complexes with inexpensive and available vicinal diamines can serve as catalysts for the reductive Heck-type cyclization. o-Bromo-N-(2-phenylallyl)anilides are converted into the corresponding 3-methyl-3-phenylindolines, the analogous cyclization occurred for 2-bromo-4-methylphenyl 2-phenylallyl ether and N-(2-bromophenyl)-2-phenylacrylamides. The use of (1R,2R)-N,N’-dibenzylcyclohexane-1,2-diamine provides up to 35% ee of the indolines; this is the first case of asymmetric induction during the reductive Heck reaction involving diamine complexes.