Selective reactions using metal phenoxides. Part 2. Reactions with aromatic alcohols

The reactions of aryloxymagnesium bromides (1) with aromatic alcohols in benzene have been studied. In most cases when an ortho-OH group is absent in the alcohol, if any reaction occurs at all it is unselective and gives mixtures of ortho- and para-products. High reactivity and ortho-regioselectivity to give 2,2′-dihydroxydi- and tri-phenylmethanes (3) are achieved with the 2-hydroxybenzyl alcohols (2), especially when the OH group is converted into the magnesium salt. The formation of ortho-quinone methides (7) as intermediates has been postulated to account for the high ortho-regioselectivity observed.