Mechanistic study of silica-gel or FeCl3-promoted ring-opening aromatization of 7-oxanorborna-2,5-dienes affording 2-bromo-3-hydroxybenzoate derivatives
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One-pot synthesis of 2-bromo-3-hydroxybenzoates by the Diels–Alder reaction of furans with bromoalkyne and the subsequent ring-opening aromatization was studied by means of deuterium-labeling experiments. The residual protons in silica gel were considered to be the hydrogen source of the hydroxy group of products under the silica gel-promoted condition. The deuterium-labeling experiment revealed a rapid equilibrium among the intermediates prior to the aromatization under FeCl3-catalyzed condition.
KeywordsOne-pot reaction Diels‒Alder reaction Bromoalkyne 3-Hydroxybenzoate Ring-opening aromatization
This work was financially supported by JSPS KAKENHI Grant Number 25410051, and by a financial incentive for cooperative research project in Graduate School of Life and Environmental Sciences, Osaka Prefecture University, granted to M.S.
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