Effect of a Strategically Positioned Methoxy Substituent on the Photochemistry of 3-Aryl-3H-1-Oxacyclopenta[ l ]Phenanthren-2-Ones

Abstract

Irradiation of 3-methoxy-3-aryl-3H-1-oxacyclopenta[ l ]phenanthren-2-one derivatives 5a–d resulted in singlet-mediated decarbonylation reaction leading to the formation of phenanthrene derivatives 9a–d . The structure of the photoproduct was unequivocally established on the basis of X-ray crystallographic analysis.