One-pot cross-coupling of N-acyl N,O-acetals with alpha,beta-unsaturated compounds.

The synergistic action of BF(3).OEt(2) and SmI(2) allowed a series of intermolecular cross-couplings of readily available N-acyl N,O-acetals with alpha,beta-unsaturated compounds to be performed in high yields, which was applied to the stereoselective synthesis of pyrrolizidine alkaloid (+)-xenovenine.