A Rh(I)‐Catalyzed Cascade Cyclization of 1,5‐Bisallenes and Alkynes for the Formation of cis‐3,4‐Arylvinyl Pyrrolidines and Cyclopentanes

Abstract The cascade cyclization reactions of 1,5‐bisallenes grant access to a great variety of products by precisely tuning the catalyst system and/or the reagents involved. Herein, we present our findings that 1,5‐bisallenes react with two molecules of dimethyl acetylenedicarboxylate to afford, in a completely diastereoselective manner, cis ‐3,4‐arylvinyl pyrrolidines and cyclopentanes. DFT calculations have been used to postulate a mechanism for the developed reaction which encompasses a [2+2+2] cycloaddition reaction of the two alkynes and the external double bond of one allene, followed by a cycloisomerization involving the internal double bond of the second allene. magnified image