Isoindole derivatives containing an azetidin-2-one moiety were prepared from phthalic anhydride by an approach that involves a [2π+2π] 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.

Highly Stereoselective Synthesis of Isoindole Derivatives Containing an Azetidinone Ring. -Isoindolylbutanoic acid (I) reacts with aromatic imines [e.g. (II) and (IV)] to give trans--lactams [e.g. (III) and (V)] stereoselectively via [2 + 2]-cycloaddition of a ketene intermediate and imines. -(HOSSEINKHANI, B.; ISLAMI, M. R.; HOSSEINKHANI, S.; Synlett 26 (2015) 16, 2277-2279, http://dx.doi.org/10.1055/s-0035-1560066 ; Dep. Chem., Shahid Bahonar Univ., Kerman 67169, Iran; Eng.) -L. Grundl 08-118