Highly Stereoselective Synthesis of Isoindole Derivatives Containing an Azetidinone Ring.

Isoindole derivatives containing an azetidin-2-one moiety were prepared from phthalic anhydride by an approach that involves a [2p+2p] cycloaddition of an imine to a novel ketene generated in situ, and an electrocyclic reaction of a zwitterionic intermediate. The reactions were highly stereoselective and trans-β-lactams were obtained as the sole observed products. [ABSTRACT FROM AUTHOR]