Photochemistry of keto-pregnane derivatives

Abstract

gave 37 per cent of 48 (R = (CH^ÏgCH-) and 22 per cent of 49. Irradiation in tertiary butyl alcohol, dioxane or benzene gave 43, 31 and 72 per cent of ^ respectively. No ^ was detected in these solvents. It would appear that the addition of solvent can compete with rearrangement in this case for solvents of low steric bulk, but that rearrangement is favored with a bulky solvent such as tertiary butyl alcohol and with those for which hydrogen abstraction is not a facile process such as dioxane and benzene.