Remote Enantioselective [4 + 1] Annulation with Copper-Vinylvinylidene Intermediates.

The first copper-catalyzed enantioselective [4 + 1] annulation of yne-allylic esters with 1,3-dicarbonyl compounds was realized through an elegant remote stereocontrol strategy. The very remote ε regioselective nucleophilic substitution was developed by employing a novel chiral copper-vinylvinylidene species from the new C4 synthon yne-allylic esters. Thus, greatly diverse spirocycles were obtained with ample scope and excellent levels of chemo-, regio-, and enantioselectivities. Moreover, detailed mechanistic studies suggest an yne-allylic substitution and Conia-ene cascade pathway on the remote stereochemical induction progress.