Photocyclization reactions. Part 2 Synthesis of dihydrobenzofuranols using photocyclization of ethyl 2-formylphenoxyacetates and ethyl 2-acetylphenoxyacetates

Photocyclization reactions were carried out on ethyl 2-formylphenoxyacetates 1a-e and ethyl 2-acetylphenoxyacetates 2a-e in acetonitrile. Irradiation of 1a-e gave dihydrobenzofuranols 3 in 20–46% yields. Similarly, irradiation of 2a-e afforded dihydrobenzofuranols 6 and their derivatives 7, 8 in 40–86% yields. Substituent effects on photocyclization and reaction pathways are discussed.