[6 + 2] AND [4 + 2] CYCLOADDITION REACTION OF DIPHENYLKETENE AND CYCLOHEPTATRIENE

Abstract

The cycloaddition reaction of diphenylketene and cycloheptatriene is studied. The reaction proceeds via a highly asynchronous reaction path to the zwitterionic 6 as intermediate. Subsequent CC- bond formation yields 8, 8 diphenylbicyclo [4. 2. I] nona-2, 4-dien-7-one (1) and 7,7-diphenylbicycol [3.2.2] nona-2, 8-dien-ri-one (2) in a 1:1 ratio as formal [6+2] and [4+2] cycloaddition products