Triethylamine → (1S,3R)-methanesulfonic acid 3-tert-butyldimethylsilyloxy-cyclopentyl ester

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Reaction Conditions

Reaction Steps

Dissolve (-)-cis-3-tert-butyldimethylsilyloxy-cyclopentanol (9.20 g, 42.5 mmol) in anhydrous tert-butyl methyl ether (50 mL) and cool to -5° C. Treat the solution with methanesulfonyl chloride (3.6 g, 46.5 mmol, mesyl chloride), followed by triethylamine (7.2 mL, 51.7 mmol), at such a rate as to keep the temperature between -5° C. and -2° C. with an ice bath. The ice bath is removed and the solution is stirred for 2 hours. The mixture is then transferred to a separatory funnel and treated with brine/water (50 mL/50 mL). The layers are separated and the aqueous layer is extracted with tert-butyl methyl ether (2×50 mL). The organic layer and extracts are combined, washed with brine, dried over anhydrous magnesium sulfate, filtered and concentrated under vacuum to provide the title compound (12.1 g, 97% yield) as a colorless oil; 1 H NMR (CDCl3) δ5.1 (m, 1H), 4.2 (m, 1H), 2.99 (s, 3H), 2.3 (m, 1H), 2.0 (m, 3H), 1.8 (m, 2H), 0.88 (s, 9H), 0.05 (s, 6H).

Provenance & Evidence