Water → 3,4-Dihydro-1H-2-benzopyran-1-ol

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Reaction Steps

To a solution of methyl-3-(2'-formyl-3'-6'-dimethoxy)phenyl-2-methoxyisopropyloxy-propionate (4.2 g, 12.4 mmol) in THF (75 ml) containing water (4 ml) was added pyridinium p-toluenesulfonate (230 mg). After stirring at room temperature for 1.75 hours, triethylamine (3 ml) and saturated NH4Cl solution (60 ml) were added. THF was removed at 25° C. and the mixture was extracted with ether (3×150 ml). Ether extract was washed with brine, dried and evaporated yielding 3.9 g of 1-hydroxyisochroman (95%) (quite pure from NMR spectrum). (MP. 127°-129° C.)

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