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.