An efficient approach to highly rigid macrocyclic bisazetidinones with interesting structural feature was achieved via sequential Staudinger ketene− imine cycloaddition of o- allyloxyphenoxyketene and bis-arylidenediamines followed by RCM. The ketene− imine cycloaddition afforded the corresponding bis-o-allyloxyphenoxyazetidinones as the cis-cis diastereomers, exclusively obtained as a mixture of cis-syn-cis and cis-anti-cis. RCM of ...
