Aromatic Hydroxylation. Hydroxybenzaldehydes from Bromobenzaldehydes via Reaction of in Situ Generated, Lithiated α-Morpholinobenzyl Alkoxides with Nitrobenzene

Article abstract of DOI:10.1021/jo00160a001

A general method for the one-step conversion of bromobenzaldehydes to the corresponding hydroxybenzaldehydes has been developed.The method involves in situ protection of the aldehyde function of the bromobenzaldehyde as its lithium morpholinoalkoxide, followed by lithium-bromine exchange, reaction with nitrobenzene at -75 deg C, and a subsequent acidic workup.The method has been applied to the synthesis of 4,5-dimethoxy-3-hydroxy- (1a), 3,5-dimethoxy-2-hydroxy- (2a), 3,5-bis(benzyloxy)-2-hydroxy- (2b), 3,4-dimethoxy-2-hydroxy- (14), 3-hydroxy-4,5-(methylenedioxy)- (16), and 4,5-dimethoxy-2-hydroxybenzaldehydes (18) from the bromobenzaldehydes 4, 12a, 12b, 13, 15, and 17, respectively.