Dual Rh(II)/Pd(0) Relay Catalysis Involving Sigmatropic Rearrangement Using -Sulfonyl Triazoles and 2-Hydroxymethylallyl Carbonates.

Dual Rh(II)/Pd(0) relay catalysis of -sulfonyl triazoles and 2-hydroxymethylallyl carbonates has been developed, which affords -sulfonyl pyrrolidines in moderate to good yields with high diastereoselectivities. The reaction proceeds via a relay mechanism involving O-H insertion onto the α-imino Rh(II)-carbene, [3,3]-sigmatropic rearrangement, dipole formation through Pd(0)-catalyzed decarboxylation, and intramolecular -allylation, leading to the formation of multiple bonds in a one-pot operation.