Diethyl 2-benzylpropanedioate → 2-Benzylpropane-1,3-diol

Beteiligte Stoffe

Reaktionsschritte

Diethyl benzylmalonate (100g.) was added dropwise to a stirred suspension of lithium aluminium hydride (12g.) in anhydrous diethyl ether (300ml.) at 0° C. under argon. The reaction mixture was then stirred overnight at room temperature and worked up by the conventional procedure, described in J. Org. Chem. 1953, 18, 1190. Evaporation of the ether solution gave 2-benzylpropane-1,3-diol. Phosphorus tribromide (26ml.) was added dropwise to this diol (44g.), whilst stirring at 75° C. After the vigorous reaction had ceased, the temperature was raised to 100° C. and maintained at this temperature overnight. The cooled mixture was poured into ice water (500ml.) and extracted with diethyl ether (2 × 500ml.). The combined ether extracts were washed with aqueous sodium bicarbonate, then brine, dried over sodium sulphate and the ether was evaporated. Distillation of the crude product in vacuo gave 2-benzyl-1,3-dibromopropane b.p. 116°-121° C./1.0 mm. Hg.

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