Diastereoselective synthesis of cis-1,3-disubstituted isoindolines via a highly site-selective tandem cyclization reaction

A highly site-selective tandem reaction involving regioselective ring opening of aziridines and Michael addition of electron-deficient alkenes has been described. O-atom nucleophiles, produced by the reaction of aldehydes and NHCs in open air, preferred to attack the less hindered aziridine carbons, followed by further intramolecular aza-Michael addition to afford a series of cis-1,3-disubstituted isoindolines in good yields with good diastereoselectivities. High selectivities, high efficiency and mild conditions made this tandem reaction very suitable for the rapid construction of libraries of isoindoline compounds.