Intramolecular Umpolung Synthesis of Exocyclic β‑Amino Alcohols through Decarboxylative Amination

An intramolecular aminative Umpolung cyclization strategy has been developed by using α,α-diphenylglycine (2) as the amination and Umpolung reagent. Aldehydes (1) bearing an additional carbonyl group underwent condensation with α,α-diphenylglycine to form an imine, decarboxylation to generate a delocalized 2-azaallylanion, and subsequent intramolecular Umpolung cyclization to produce a variety of exocyclic β-amino alcohols (6) in 60–93% yields with up to >20:1 trans/cis selectivity under mild conditions.