Overcrowded molecules. Part II. The interaction of diphenylketen with 2-benzylidene-1,3-indanedione

Abstract

Diphenylketen and 2-benzylidene-1,3-indanedione react at 160° to yield 5,10-diphenylbenzo[b]fluoren-11-one, 5,10-dihydro-5,10-diphenyl-11-diphenylmethylene-11H-benzo[b]fluorene, and 3,4-dihydro-3,3,4-triphenyl-5-diphenylmethyleneindeno[1,2-b]pyran-2-one. The first two products are believed to be formed by the dehydrocyclisation and cyclisation of 2-benzylidene-3-diphenylmethylene-1-indanone and 1,3-bisdiphenylmethylene-2-benzylideneindane, respectively.