A vinylogous Michael reaction of 2-furanone dimers with α,β-unsaturated nitroolefins for constructing chiral γ,γ-disubstituted butenolides

An efficient bifunctional thiourea catalyzed asymmetric vinylogous Michael addition of 2-furanones dimers to α, β-unsaturated nitroolefins has been developed to give the functional chiral γ,γ-disubstituted butenolides in good yields (up to 95%) with good to excellent stereoselectivity (up to >20:1 dr, 99% ee). DFT calculations were carried out to explain the high stereoselectivity.