Intramolecular Cycloadditions to Oxyallyl Zwitterions Generated from Photorearrangements of 2,5-Cyclohexadien-1-ones

Article abstract of DOI:10.1021/jo00237a030

Photorearrangement of 2,5-cyclohexadien-1-one 9a gave phenols 12 and 13, while 9b gave bicyclo<3.1.0>hexenone 10b.No evidence for the formation of an azide-zwitterion cycloadduct was obtained from these examples.However, the 3,6-dimethoxy analogue 9c provided the bridged triazene 14, for which X-ray crystallographic studies confirmed structural assignments for 14 and previously obtained triazenes 5a and 5b. 4-<3-(2-furyl)propyl>-3-methoxy-4-(nethoxycarbonyl)cyclohexa-2,5-dien-1-one (17) photorearranged to bicyclohexenone 18 and phenol 19.The 4-acetoxymethyl derivatives 20a and 20b gave the bridged furan adducts 23a, and 23b in excellent yield.Acetoxymethyl-substituted triazene 27 was obtained from 26c; 27 slowly gave alcohol 28 on exposure to the atmosphere.