Improved efficiency and product selectivity in the photo-Claisen-type rearrangement of an aryl naphthylmethyl ether using a microreactor/flow system

摘要

Ultraviolet (UV) irradiation of 2-[(2,4,6-trimethylphenoxy)methyl]-1- (methoxycarbonyl)naphthalene promotes a photochemical reaction that gives a cyclohexa-2,4-dienone product arising from a photo-Claisen-type ortho-rearrangement and a phenol derivative arising from a meta-rearrangement, along with 1-methoxycarbonyl-2-methylnaphthalene and 1,2-bis[1-(methoxycarbonyl) naphthalen-2-yl]ethane. When this process is carried out in a microreactor/flow system, its efficiency is dramatically enhanced and selectivity of products is improved. The effects on efficiency and product selectivity caused by the microreactor/flow system are attributed to more efficient light absorption and the suppression of secondary reactions.