Preparation of furans by palladium-catalyzed reaction of acylchromates and propargylic tosylates

摘要

Substituted furans are prepared by the palladium-catalyzed reaction of propargylic tosylates with acylchromates. The reaction is initiated by the oxidative addition of propagylic tosylates to palladium(O) complexes to give 1,2-propadienylpalladium(II) complexes, which in turn react with acylchromates to form 1,2-propadienyl ketones. Then 1,2-propadienyl ketones are transformed to furans by the action of in situ generated Cr(CO)_5.