Organocatalytic Asymmetric Synthesis of Sulfonyl-Substituted Furans via a Cascade 1,6-Addition/Cyclization/Enantioselective Protonation Pathway

An efficient cascade 1,6-addition/cyclization/enantioselective protonation pathway between ene-yne-ketones and sodium sulfinates was realized. This protocol provides practical access to various sulfonyl-substituted furans in good yields and high enantioselectivities under mild reaction conditions. Control experiments and density functional theory calculations were conducted to elucidate the plausible reaction mechanism and the origins of stereoselectivity.