Photoadditions of 1- and 2-Naphthols and Derivatives to Acrylonitrile. Conversion of the Cyclobutane Adducts to Cyanoethylnaphthols

Article abstract of DOI:10.1021/jo00320a041

The photoreactions of 1- and 2-naphthol, their trimethylsilyl (Me3Si) ethers, and 1-methoxynaphthalene with acrylonitrile in a 1:1 isopropyl alcohol-tert-butyl alcohol mixture have been investigated.Irradiation of 2-naphthol and acrylonitrile gives 7-cyano-2,3-benzobicyclo<4.2.0>octa-2,4-dien-6-ol (3) while 2-naphthol trimethylsilyl ether gives the trimethylsilyl ether of 3.Base treatment of 3 or 3 trimethylsilyl ether gave 1-(2-cyanoethyl)-2-naphthol.Photoaddition of 1-naphthol trimehylsilyl ether and acrylonitrile gives8-cyano-2,3-benzobicyclo<4.2.0>octa-2,4-dien-1-ol trimethylsilyl ether, which is converted to the parent alcohol (6) by acid or to 2-(2-cyanoethyl)-1-naphthol (7) by base.The latter was also isolated in poor yield from the photolysis of 1-naphthol and acrylonitrile.Photoaddition of 1-methoxynaphthalene and acrylonitrile affords 1-methoxy-8-cyano-2,3-benzobicyclo<4.2.0>octa-2,4-diene (8) and endo-4-methoxy-7-cyano-2,3-benzobicyclo<4.2.0>octa-2,4-diene (9), in the ratio 1:1. 2,6-Dimethoxynaphthalene adds to acrylonitrile, giving the 7-cyano-6-methoxy-2,3-(2'-methoxy)benzobicyclo<4.2.0>octa-2,4-diene (16).These photoadditions are of possible synthetic utility for the ortho cyanoethylation of phenols.