Copper-Catalyzed Vinylogous Mannich Reaction of Sulfonylimines

Significance

In prior work the authors have reported that catalyst 1 is effective for both Mannich and formal aza Diels-Alder reactions of N-sulfonyl­imines (J. Am. Chem. Soc. 2004, 126, 456). In the present paper, the utilization of N-(2-thienyl)sulfonyl imines provides vinylogous Mannich products of acyclic silyl dienol ethers and 2-trimethylsilyloxyfuran in high yields and ee values with nearly complete γ-selectivity. Furthermore, the authors demonstrate that the 2-(thienyl)sulfonyl group undergoes facile deprotection by treatment with Mg in MeOH.