Hydrogen Peroxide → 2,2-Difluoro-1-benzyloxy-5-hydroxypentane

Participants

Reaction Steps

To a mixture of (29) (16.8 g, 79 mmoles) and sodium borohydride (901 mg, 23.7 mmoles, 20% excess) in dry tetrahydrofuran (75 ml), kept under nitrogen at room temperature, borontrifluoride-ether complex (4.07 ml, 31.6 mmoles, 20% excess) is added over a period of 25 min. After standing for 13/4 hours at room temperature, the reaction mixture is slowly hydrolyzed with water (6 ml). Addition of 3N NaOH (10 ml) is followed by careful introduction of hydrogen peroxide (10 ml, 30%) at such a rate that the internal temperature does not exceed 40° C. The temperature is then allowed to return to room temperature, and the reaction mixture is diluted with ether and brine. Usual work-up affords a mixture of isomeric alcohols (17.2 g) which is separated by chromatography on silica (ethyl acetate/petroleum ether: 15/85, RF: 0.1) to give 9.8 g (54%) of the title compound.

Provenance & Evidence