A highly diastereoselective synthesis of tricyclic lactams and their application as novel N-acyl iminium ion precursors in the synthesis of isoindolinone derivatives

Condensation of 2-formylbenzoic acid with α-amino alcohol substrates proceeds with extremely high diastereoselectivity to produce tricyclic γ-lactam products. The relative stereochemistry of the major diastereoisomer has been determined by X-ray crystal analysis and a mechanism suggested to explain the stereochemical outcome. Further, we report that this class of heterocycle can act as an N-acyl iminium ion precursor in the synthesis of substituted isoindolinone derivatives.