2-Aryl- and 2-alkylfurans are converted into the corresponding 5-organyl-2(3H)-butenolides by the oxidation of boron derivatives with m-chloroperbenzoic acid.
Chiral phosphine-catalyzed asymmetric (4+2) annulation of the amide-based Morita–Baylis–Hillman (MBH) carbonates with β,γ-unsaturated butenolides has been developed to give enantiomer-enriched bicyclic δ-lactam γ-butyrolactone compounds. The amide-based MBH carbonates were first used as acceptor and aza-C4 synthon in phosphine catalysis. Under mild reaction conditions, a variety of amide-based MBH