Highly Enantioselective Synthesis of Cyclic Aminals with a Cyclopentadiene‐Based Chiral Carboxylic Acid

Abstract

A highly enantioselective aminalization of 2‐aminobenzenesulfonamides and aldehydes catalyzed by a novel cyclopentadiene‐based chiral carboxylic acid has been realized. The cost‐effective and readily synthesized cyclopentadiene‐based chiral carboxylic acid was found to be a highly reactive Brønsted acid for this transformation, affording benzothiadiazine class of cyclic aminals with up to 98 % ee .