A synthesis of 4, 4-diphenyl-γ-pyran (1) was elaborated from diphenylmethane. Prolonged irradiation of pyran 1 in tert-butyl alcohol led to: trans-endo-5, 6-diphenyl-2-oxabicyclo [3.1. 0]-hexene (18), isomeric 3, 5-diphenylpenta-2, 4-dienals (6), trans-tert-butyl 3, 5- diphenylpent-2-enoate (7), cis-tert-butyl 3, 5-diphenylpent-2-enoate (8), and isomeric 3, 5- diphenylpent-2-enoic acids (9). It was established that the photolysis of γ-pyran 1 yields ...