Additionally, the resulting silyl enol ether unit from the [4+3] cycloadducts could be further transformed to ketone 11 via desilylation and α-hydroxyketone 12 via dihydroxylation. Importantly, owing to its generality with respect to silyl enol ethers, this method could be applied to late-stage modifications of natural products, as bridged polycycles 13 and 14 were formed in synthetically useful yield from commercially available dihydro-β-ionone and cholestenone through ketone silylation and formal cycloaddition sequence (Scheme 2).