Enantioselective Gold(I)-Catalyzed Vinylogous [3 + 2] Cycloaddition between Vinyldiazoacetates and Enol Ethers

The reaction of vinyldiazoacetates with enol ethers catalyzed by the binuclear gold complex (R)-DTBMSegphos­(AuCl)2 activated by silver hexafluoroantimonate results in a highly enantioselective [3 + 2] cycloaddition. The [3 + 2] cycloaddition proceeds with dynamic kinetic resolution when the enol ether is a 4-substituted 1-(methoxymethylene)­cyclohexane. The reaction is initiated by nucleophilic attack of the vinyl ethers at the vinylogous position of the gold vinylcarbene intermediate.