Copper-Catalyzed Asymmetric Kinugasa/Michael Addition Cascade Reactions for the Synthesis of Chiral Spiro β-Lactams

Abstract

A mild copper-catalyzed asymmetric Kinugasa/Michael addition cascade process is developed. The reaction of α, βunsaturated ester-tethered propiolamides with nitrones provides an efficient protocol for the construction of functionalized chiral 2,6-diazaspiro[3.4]octane-1,5-dione products in satisfactory yields and with high enantio-and diastereoselectivities.