Effect of ortho-hydroxy substituent on photochemistry of 2-bromo-1-phenylalkan-1-ones: Remote bromine atom shift reaction

Abstract

Irradiation of 2-bromo-1-(2-hydroxy)phenylalkan-1-ones forms ring-brominated phenyl ketones, where bromine moves from the α-position of the carbonyl to the phenyl ring. The unprecedented remote Br shift reaction occurs with regioselectivity favoring the ortho isomer, which originates from a hypobromite intermediate. The reaction has several advantages over other known methods for the preparation of the ring-brominated 1-(2-hydroxy)phenylalkan-1-ones: no poly-bromination, ortho-selectivity, no additives, use of eco-friendly light energy only, and no bromination at other active sites such as the benzylic position.