The synthesis of 3‐substituted 4‐phenyl‐1‐(9,10‐dihydrophenanthren‐3‐yl)azetidin‐2‐ones was achieved following Staudinger cycloaddition under microwave‐induced conditions. The stereoselectivity of β‐lactam formation depended on the power level of the microwave irradiation used in the experiments.