Irradiation of 1-hydroxy-1,3-diphenyl-2-indanone (1) leads to the formation of two intermediates assigned to the enols (E,E and Z,E). The Z,E-enol is short lived, and its possible decay mode involves product formation from which ortho-benzylbenzophenone is the main product. The longer lived E,E-enol shows a lifetime of > 100 ms in methanol, and its decay results in the formation of a complex mixture of products, with 10-phenylanthrone and 10-hydroxy-10-phenylanthrone being the main ones. Laser flash photolysis of 1-hydroxy-1,3,3-triphenyl-2-indanone (2) shows the formation of the two possible photoenols Z (t = 180 ns) and E (t = 30 ms). The decay mode for these enols is product formation, resulting in a complex mixture of products.
photoenols; 1-hydroxy-2-indanones; laser flash photolysis
