Overcrowded molecules. Part I. 1,2-Bisdiphenylmethyleneindane and 1,2-bisdiphenylmethylene-3,3-dimethylindane

Abstract

1,2-Bisdiphenylmethyleneindane and its 3,3-dimethyl derivative have been prepared by the interaction of diphenylketen and 2-diphenylmethylene-1-indanone and its 3,3-dimethyl derivative, respectively. These severely overcrowded hydrocarbons are stable but, when dissolved in organic solvents and exposed to sunlight, they cyclise to give dihydrotriphenyl-11-H-benzo[b]fluorenes and their derivatives.