Toluene → (R)-(+)-1-Phenyl-1,3-propanediol

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Reaction Steps

To a solution of (-)-(2S,3S)-epoxycinnamyl alcohol (1) (1.5 g, 10.0 mmol) (synthesized by the method disclosed in Gao et al., J. Org. Chem., Vol. 53, No. 17, pp. 4081-4084 (1988.), in dimethoxyethane (50 mL) was added a 3.4 molar solution of Red-Al® in toluene (3.1 mL, 10.5 mmol) dropwise under nitrogen at 0° C. After stirring at room temperature for three hours, the solution was diluted with ether and quenched with 5% HCl solution. After stirring at room temperature for 30 min, the resulting white precipitate formed was filtered and boiled with ethyl acetate and filtered again. The combined organic solutions were dried with magnesium sulfate. Concentration gave (R)-3-phenyl-1,3-dihydroxypropane (2) as a slightly yellow oil which was used without further purification (1.5 g, 98%): 1H NMR (CDCl3) δ7.2-7.3 (m, 5 H), 4.88-4.98 (m, 1 H), 3.78-3.86(t, J=7.5 Hz, 2), 3.3-3.4 (br. s, 1 H), 2.85-2.95 (br. s, 1 H) , 1.84-2.08 (m, 2 H); the ratio of 1,3-diol to 1,2-diol was 20:1 by 1H NMR analysis of the derived diacetate.

Provenance & Evidence