Asymmetric Synthesis of Isoindolines Featuring <i>N</i> ‐substituted Quaternary Carbon Centers through Stereoselective Intramolecular Aza‐Michael Reactions

This paper describes the asymmetric construction of N-substituted quaternary carbon centers through the phase-transfer-catalyzed stereoselective intramolecular aza-Michael reaction of β,β-disubstituted, α,β-unsaturated esters, and nitriles with chiral sulfinamides used as nucleophiles. This reaction efficiently yielded chiral 1,1-disubstituted isoindolines with yields ranging from 41% to 90% and excellent diastereoselectivities (diastereomeric ratio between 7.8:1 and > 20:1).