π-Stacking Effect on Levoglucosenone Derived Internal Chiral Auxiliaries. A Case of Complete Enantioselectivity Inversion on the Diels−Alder Reaction

Detailed quantum chemical calculations, experimental evidence, and NMR data rationalize the participation of π-stacking interaction in the highly asymmetric Diels−Alder reaction using levoglucosenone derived internal chiral auxiliaries, including the appealing effect of inversion of the enantioselectivity by coordination of the substrate with Et₂AlCl.