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 co-catalyst 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%. [reaction: see text]
Aroyan
Carrie E
CE
Department of Chemistry, Merkert Chemistry Center, Boston College, Chestnut Hill, MA 02467, USA.
Vasbinder
Melissa M
MM
Miller
Scott J
SJ