p-Toluenesulfonic acid → Ethanone, 2-bromo-1-(2,2-dimethyl-4H-1,3-benzodioxin-6-yl)-

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Reaction Steps

2-Methoxypropene (10 g) was added over 15 min to a stirred solution of 2-bromo-1-[4-hydroxy-3-(hydroxymethyl)phenyl]ethanone (5 g) and toluene-4-sulphonic acid (0.5 g) in CH2Cl2 (100 ml) at 23°. The mixture was stirred for 3 h, filtered through a was of triethylamine-deactivated silica and evaporated to give an oil. Purification by [FCTS] (300 g) [E] afforded the title compound as an oil (4.8 g) which solidified on cooling. A small sample was crystallised from light petroleum (b.p. 60°-80°) to give white crystals m.p. 47°-48°.

Provenance & Evidence