Highly syn-diastereoselective Michael addition of enolizable ketones to 3-(diethoxyphosphoryl)coumarin

摘要

A new approach to 3-(diethoxyphosphoryl)-4-(2-oxoalkyl)-3,4-dihydrocoumarins by base promoted conjugate addition of enolizable ketones to 3-(diethoxyphosphoryl)coumarin is described. The resulting products were transformed into the corresponding α-methylene-d-lactones. A transition state model rationalizing stereochemical outcome of the reaction is proposed.