The preparation and photolysis of some vinylogous imides

The preparation and photochemistry of three vinylogous imides is described. Two of these were used in the investigation into the mechanism of the intramolecular photo ene reaction. The results indicate that the carbon-carbon bond formation probably precedes hydrogen abstraction, if the reaction is free radical in nature. This is consistent with results from other investigations. The third vinylogous imide was shown to undergo regiospecific and stereospecific intermolecular [2+2] cycloaddition in high yield. This is also consistent with results obtained from other vinylogous imide systems.