PHOTOCYCLOADDITION OF ETHENES TO CYANOANISOLES

Article abstract of DOI:10.1016/S0040-4020(01)85924-X

The photoreactions of 2-, 3-, and 4-cyanoanisole with cis cyclo-octene, ethyl vinyl ether and acrylonitrile have been investigated.Additions of cyclo-alkene reflect control of the reaction by the methoxy group to give predominantly meta cycloadducts by 2,6-attack.In contrast these arenes and ethyl vinyl ether undergo ortho cycloaddition which in the case of the product from the 2-arene isomer, leads to a convenient high yield synthesis of the bicyclo<4.2.0>octa-2,7-diene (23).The reactions of acrylonitrile with 2- and 3-cyanoanisoles are slow and non-selective but ortho cycloadducts are formed from the 4-isomer which also undergoes novel photoaddition with the cyano group of both acrylonitrile and benzonitrile to give azacyclo-octatetraenes.