One-Pot Strategies Using Rhodium(II) Azavinyl Carbenes for the Synthesis of 2,4-Substituted Pyrrolidines

We herein report a simple one-pot methodology for the synthesis of pyrrolidines involving the Rh(II)-catalyzed transannulation and rearrangement of N-sulfonyl-1,2,3-triazoles and styrenes, followed by a mild iodine/hydrosilane-mediated reduction. The optimized process affords pyrrolidines in yields ranging from 40 to 85%. Preliminary mechanistic studies highlight the role of hydrogen iodide in the reduction step. Additionally, an iodine-promoted cyclopropylimine rearrangement and reduction was investigated as a potential alternative pathway. The general strategy provides a practical, functional-group-tolerant approach to efficient preparation of pyrrolidines.