A convenient method for the preparation of 4-aryloxyphenols

Article abstract of DOI:10.1055/s-1991-26381

A convenient method for the preparation of 4-aryloxyphenols via the homologation of preformed phenols is described. Condensation of various 4-substituted phenols with either 4-fluorobenzaldehyde (8) or 4-fluoroacetophenone (9) yielded the corresponding 4-aryl-oxybenzaldehydes, 10, and acetophenones, 11, in 70-93% yield. Baeyer-Villiger oxidation of these materials with 3-chloroperoxybenzoic acid (MCPBA) yielded the corresponding 4-formyloxy and 4-acetoxyphenyl ethers which were hydrolyzed without purification to the desired 4-aryloxyphenols 12 in 72-94% yield. Both 4-fluorobenzaldehyde (8) and 4-fluoroacetophenone (9) are synthetically equivalent to the a⁴ umpoled synthon 6. Extension of this methodology of the preparation of 4,4'-[arylbis(oxy)]bisphenols from aromatic diols is also described. Condensation of various aromatic diols with 8 or 9 yielded the corresponding 4,4'-[arylbis(oxy)]bisbenzaldehydes 15 and acetophenones 16 in 71-89% yield. Baeyer-Villiger oxidation of these compounds with MCPBA yielded the desired 4,4'-[arylbis(oxy)]bisphenyl bisformates 17 and bisacetates 18 in 67-84% yield. Hydrolysis of these compounds afforded the desired 4,4'-[arylbis(oxy)bisphenols 19 in 70-91% yield.