Rate acceleration of triethylamine-mediated guanidine-catalyzed enantioselective Michael reaction

Article abstract of DOI:10.1002/adsc.200800423

A chiral bicyclic guanidine was found to be an excellent catalyst for enantioselective Michael reactions. It was observed that additives such as non-chiral amines could accelerate the rate of reaction. When triethylamine (Et₃N) was as used as the solvent, the reaction rate can be increased up to 1000 times without compromising the enantioselectivity. Michael acceptors such as 2-cyclopenten-1-one 2 and N-alkylmaleimides were investigated, with various commercially available Michael donors such as dialkyl malonates and benzoylactetates. Michael adducts were obtained in excellent enantiomeric excesses (up to 96%) and yields (up to 99%).