Stereoselective Synthesis of Pyrrolidines from Aziridinols

Significance

A regio- and stereoselective synthesis of pyrrolidines from aziridinols via a one-carbon homologative ring expansion initiated by an aza-Payne rearrangement is reported. Using chiral starting materials results in excellent chirality transfer to the product pyrrolidines. Initial room temperature conditions are required in order to avoid the direct attack of aziridines by dimethylsulfoxonium methylide. The yield is slightly higher for cis compared to trans aziridinols presumably because of the greater release of strain in the former systems. Application of microwave technology to the ylide reaction for three cases afforded higher or comparable yields under substantially reduced times (˜8 min vs 24 h).