Solid state photochemical reaction of N-(alpha,beta-unsaturated carbonyl)benzoylformamides

Photochemical reactions of various N-(alpha,beta-unsaturated carbonyl)benzoylfomamides both in solution and in a solid state were investigated. Under homogeneous conditions, all acyclic imides underwent photochemical 2 + 2 cycloaddition that resulted in the production of bicyclic oxetanes. N-Isopropyl- and N-benzyl-N-tigloylbenzoylformamides crystallized in a chiral space group, and the photolysis in the solid state yielded corresponding optic ally-active oxetanes. N-Tigloylbenzoylformanilide underwent cis-trans isomerization to yield a photostationary state (cis/trans = 1.3). Solid state oxetane formation of N-benzyl- and N-(o-tolyl)- and N-(2,6-xylpl)-N-tigloylbenzoylformamides progressed via the crystal-to-crystal pathway which was followed by X-ray powder diffraction, N-Benzyl-N-methacryloylbenzoylformamide crystallized in a chiral space group, and the solid state reaction led to an optically active beta-lactam via topochemically-controlled hydrogen abstraction by the alkenyl carbon atom. Photolysis of N-isopropyl-N-methacryloylbenzoylformamide in the solid state led to both oxetane formation and a transformation to azetidine-2,4-dione involving a 1,5-benzoyl shift.