Overcrowded molecules. Part III. The synthesis and photorearrangement reactions of 2,3-bisdiphenylmethylene-1-indanone and 4b,5-dihydro-5,5,10-triphenyl-11-diphenylmethylene-11H-benzo[b]fluorene

Abstract

2,3-Bisdiphenylmethylene-1-indanone, prepared by the interaction of diphenylketen and an excess of 2-diphenylmethylene-1,3-indanedione, reacts with diphenylketen at 160° to yield 11-diphenylmethylene-4b,5-dihydro-5,5,10-triphenyl-11H-benzo[b]fluorene through the thermal rearrangement of 1,2,3-trisdiphenylmethyleneindane. The overcrowded compounds 2,3-bisdiphenylmethylene-1-indanone and 11-diphenylmethylene-4b,5-dihydro-5,5,10-triphenyl-11H-benzo[b]fluorene, when dissolved in light petroleum and exposed to sunlight, cyclise to yield 10,10a-dihydro-5,10,10-triphenylbenzo[b]fluoren-11-one and 9,9a,13b,14-tetrahydro-9,9,14,14-tetraphenyldibenzo[b,e]fluoranthene, respectively.