Phosphine-catalyzed [3+2] annulation of beta-sulfonamido-substituted enones with trans-alpha-cyano-alpha,beta-unsaturated ketones for the synthesis of highly substituted pyrrolidines

To synthesize highly substituted pyrrolidines, we developed a phosphine-catalyzed [3 + 2] annulation of beta-sulfonamido-substituted enones with trans-alpha-cyano-alpha,beta-unsaturated ketones. We prepared a series of pyrrolidines under mild conditions with high yields and moderate-to-good diastereoselectivities. A catalytic mechanism for this reaction is suggested.