(Trifluoromethyl)trimethylsilane → (2R,3R)-3-(tert-Butyl-dimethylsilanyloxy)-2-[(1R)-(2,2,2-trifluoro-1-hydroxyethyl)]pyrrolidine-1-carboxylic acid tert-butyl ester

Beteiligte Stoffe

Reaktionsschritte

To aldehyde 51C (2.10 g, 6.38 mmol) was added trimethyl(trifluoromethyl)silane (800 μL, 6.57 mmol) and cesium fluoride (dried under high vacuum at 130° C. for 12 h) (10.0 mg, 0.0658 mmol). The reaction was stirred at rt for 24 h then heated to 50° C. for 5 h. After cooling to rt, 4 N HCl (ca. 10 mL) was added and the reaction was stirred overnight. The brown aqueous solution was decanted and the waxy yellow solid was dried under high vacuum overnight then recrystallized from hexane to provide (2R,3R)-3-(tert-butyl-dimethyl-silanyloxy)-2-[(1R)-(2,2,2-trifluoro-1-hydroxy-ethyl)]-pyrrolidine-1-carboxylic acid tert-butyl ester (66A) (1.19 g) as a white solid. The mother liquor was concentrated and purified via flash chromatography eluting with 5-20% ethyl acetate/hexane to provide (2R,3R)-3-(tert-butyl-dimethyl-silanyloxy)-2-[(1S)-(2,2,2-trifluoro-1-hydroxy-ethyl)]-pyrrolidine-1-carboxylic acid tert-butyl ester (66B) (192 mg) as an oil and a mixture of 66A and starting material 51C (306 mg). The latter mixture was recrystallized from hexane to provide additional 66A (100 mg).

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