Asymmetric Formal Coupling of ß-Ketoesters with Quinones Promoted by a Chiral Bifunctional N-Heterocyclic Olefin.

ABSTRACT

A highly enantioselective formal coupling of ß-ketoesters with quinones was accomplished by a chiral bifunctional N-heterocyclic olefin organocatalyst. With as low as 1 mol % catalyst loading, a number of enantioenriched quinone derivatives were afforded in good yields with high enantioselectivities and regioselectivities (up to 96% yield, 98% ee, and 191 rr). Gram-scale synthesis and the high inhibitory effect of several products on the viability of cancer cells demonstrate the potential utility of the current method.