Organocatalytic\nAsymmetric Synthesis of Sulfonyl-Substituted\nFurans via a Cascade 1,6-Addition/Cyclization/Enantioselective Protonation\nPathway

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