Asymmetric Auto-Tandem Catalysis with Chiral Organosuperbases: Intramolecular Cyclization/Enantioselective Direct Mannich-Type Addition Sequence

Org Lett. 2024 Aug 2;26(30):6523-6528. doi: 10.1021/acs.orglett.4c02532. Epub 2024 Jul 19.

Abstract

An enantioselective addition reaction of alkynyl esters with imines was developed under asymmetric autotandem catalysis with a chiral Brønsted base. A chiral bis(guanidino)iminophosphorane organosuperbase, which has much higher basicity than that of conventional chiral organic bases, efficiently promoted both the intramolecular cyclization for the construction of a benzofuran ring or a benzothiophene ring and the sequential enantioselective direct Mannich-type reaction of diarylmethane derivatives, affording enantio-enriched diarylalkane derivatives that are otherwise difficult to access.