ADDITION-REACTION OF PHOTOENOLS FROM O-METHYL-SUBSTITUTED AROMATIC KETONES WITH 5-ALKYLIDENE-1,3-DIOXANE-4,6-DIONE DERIVATIVES

Photolyses of 2-methylacetophenone or 2-methylbenzophenone with isobutylidene Meldrum's acid or 5-isobutylidene-1,3-dioxane-4,6-dione derivatives produced novel adducts, bonding between the beta-carbon of the acylals and the 2-methyl carbon of the aromatic ketones. However, the photoenol derived from benzocyclobutenols by thermolysis did not undergo the addition reaction with the acylal. The benzocyclobutenols reacted with isobutenylketene derived by pyrolysis of isobutylidene Meldrum's acid to yield corresponding benzocyclobutenyl 4-methyl-3-pentenoate derivatives.