Ethyl Acetate → (2S,4R)-N-t-butoxycarbonyl-4-t-butyldimethylsiloxy-2-[alpha-hydroxy-3-(tetrahydropyranyloxymethyl)benzyl]pyrrolidine

Beteiligte Stoffe

Reaktionsbedingungen

Reaktionsschritte

A solution of 3-(tetrahydropyranyloxymethyl)bromobenzene (11.8 g, 43.5 mmol) in tetrahydrofuran (20 ml) was added dropwise to a solution of 1.6M n-butyl lithium-hexane solution (30 ml, 48 mmol) in tetrahydrofuran (100 ml) at -78° C. in a nitrogen stream over 15 minutes. This reaction solution was stirred at -78° C. for 40 minutes and then a solution of (2S,4R)-N-t-butoxycarbonyl-4-(t-butyldimethylsiloxy)prolinal (7.2 g, 21.9 mmol) in tetrahydrofuran (20 ml) was added dropwise over 20 minutes. The reaction solution was stirred at -78° C. for 30 minutes and then allowed to gradually warm and saturated aqueous ammonium chloride was added thereto. This solution was poured into a liquid mixture of ethyl acetate with water and the organic layer was washed with saturated aqueous sodium chloride, dried over anhydrous sodium sulfate, and concentrated in vacuo. The resulting oily residue was subjected to silica gel column chromatography (Wakogel™ C-300, heptane-ethyl acetate=6:1) to give (2S,4R)-N-t-butoxycarbonyl-4-t-butyldimethylsiloxy-2-[α-hydroxy-3-(tetrahydropyranyloxymethyl)benzyl]pyrrolidine (6.3 g, yield: 55.0%) as a yellow oily substance.

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