Dual catalyst control in the enantioselective intramolecular Morita-Baylis-Hillman reaction

The intramolecular Morita-Baylis-Hillman (MBH) reaction has been achieved with unprecedented levels of enantioselectivity. Using a cocatalyst system involving pipecolinic acid and N-methylimidazole, cyclic MBH products have been obtained with enantiomer ratios of 92:8 (84% ee). In addition, reactions may be carried out with a kinetic resolution quench involving acetic anhydride and an asymmetric acylation catalyst such that ee enhancement occurs to deliver products with > 98% ee with an isolated yield of 50%.