Allenic amides are successfully developed
as dipolarophiles to
react with vinyl epoxides under Pd-catalysis. The chiral NHC showed
its unique role as the ligand in this asymmetric [3 + 2] cycloaddition.
Chiral tetrahydrofurans bearing three functional groups (monosubstituted
alkene, tetrasubstituted enolether, and amide) and vicinal tertiary
and quaternary stereocenters were obtained in high yields with high
diastereo- and enantioselectivities.