4-Toluenesulfonyl chloride → (3R,3aS,6R,6aS)-6-[(4-methylbenzenesulfonyl)oxy]-hexahydrofuro[3,2-b]furan-3-yl 4-methylbenzene-1-sulfonate

Participants

Reaction Conditions

Reaction Steps

Isomannide (40) (50 g, 342.5 mmol) and p-toluenesulphonyl chloride (143.6 g, 753.2 mmol) were dissolved in a mixture of carbon tetrachloride (300 mL), dichloromethane (30 mL) and water (250 mL). The flask was cooled to 0° C. and a solution of potassium hydroxide (42.0 g, 750.0 mmol) in water (42 mL) added dropwise over 2 hours with stirring under argon. The resulting biphasic mixture was stirred vigorously at 0° C. for 24 hours. The resulting off-white precipitate, comprising a mixture of mono- and bistosylates (approximately 1:1), was collected by filtration in vacuo. The filter cake was washed with water then triturated with methanol (500 mL). The solid was isolated by filtration in vacuo to obtain ditosylate (39) as an off-white powder (75 g, 48%). [α]D18+96.7° (c=10.5, CHCl3).

Provenance & Evidence