Zinc-promoted reactions. 8. The effect of ring strain in the reduction of 1,2-dibenzoylcycloalkanes

Abstract Ring cleavage was the main route in the Zn reduction of 1 in neat AcOH, while selective carbonyl reduction predominated in the presence of LiCl. The less strained 2 underwent only carbonyl reduction with Zn/AcOH. The Clemmensen reduction of both 1 and 2 resulted mainly in acyclic products. The unstrained 3 was fairly resistant towards reduction, and did not undergo ring cleavage.