Butanal → (2R,3R,4R)-3,4-dibenzyloxy-2-benzyloxymethyl-1-butylpyrrolidine

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Reaction Steps

(2R,3R,4R)-3,4-Dibenzyloxy-2-benzyloxymethylpyrrolidine (Compound 1) (0.7 g, 1.7 mmol) was dissolved in dry methanol. Butyric aldehyde (0.153 ml, 1.7 mmol) and sodium cyanoborohydride (0.107 g, 1.7 mmol) was added. A solution of anhydrous hydrogen chloride in diethylether (2 M) was added dropwise until pH 6. The resulting mixture was stirred for 24 hours at room temperature under a nitrogen atmosphere and evaporated in vacuo. Addition of 1M sodium hydroxide (50 ml), extraction of the product with diethylether (2×50 ml), drying of the organic phases with magnesium sulphate and evaporation of the solvent in vacuo gave the title compound as a crude oil (0.644 g). Purification of the crude product on a silica gel column (Eluent: methylene chloride/methanol (19:1)) afforded (2R,3R,4R)-3,4-dibenzyloxy-2-benzyloxy-methyl-1-butylpyrrolidine (0.243 g, yield: 30%) as an oil.

Provenance & Evidence