Au-Catalyzed Diastereoselective [3+2] Cycloaddition

Significance

A gold-catalyzed diastereoselective [3+2] cycloaddition of an allenyl MOM ether with enals or enones is shown to create synthetically useful cyclopentanone enol ethers with all-carbon quaternary centers. The one-pot, two-step reaction first involves silylation of the enal or enone (which increases selectivity) followed by cycloaddition, eliminating the isolation of the delicate intermediate. The scope is broad for both acyclic and cyclic enals and enones with single diastereo­mers seen.