1993 年 41 巻 3 号 p. 471-477
The photocycloaddition reaction of 4, 5-diethoxycarbonyl-1H-pyrrole-2, 3-dione 4 to acyclic olefins proceeded in a regioselective manner to give two head to tail adducts, the exo- (5) and endo-isomers (6). The stereochemistry of the 7-substituents of the adducts changed depeding on the electronic properties of olefins. Olefins with O-substituents(ethoxyethylene, acetoxyethylene) stereoselectively gave the endo-adducs (6d, e). Olefins with phenyl and ethyl substituents, styrene and 1-butene, gave a mexture of the exo- (5a, b) and endo-adducts (6a, b) with exo-preference.Butadiene gave the exo- (5b) and endo-adduct (6b) with slight excess of the latter. These stereochemical results are in good accordance with the predictions obtained by the sterep-selection rule of enone-olefin photocycloaddition.
