Catalytic Asymmetric Synthesis of Chiral Bis(indolyl)methanes Using a Ts-PyBidine-Nickel Complex

J Org Chem. 2019 Nov 1;84(21):14248-14257. doi: 10.1021/acs.joc.9b02006. Epub 2019 Oct 11.

Abstract

A chiral tosyl-substituted bis(imidazolidine)pyridine Ts-PyBidine-nickel complex was an efficient catalyst for Friedel-Crafts reaction of indoles with methylene indolinones to give bisindolylmethane compounds having differently oxidized indole units with high enantioselectivities. Alkylation of the products proceeded smoothly in a highly diastereoselective manner, providing an all-carbon quaternary carbon center without significant loss of enantiomeric excess.