4-Toluenesulfonyl chloride → tert-butyl (3R)-3-methyl-4-(p-toluenesulphonyloxy)butyrate

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Reaction Steps

p-Toluenesulphonyl chloride (13.2 g) was added portionwise to a stirred mixture of tert-butyl (3R)-4-hydroxy-3-methylbutyrate (11 g), triethylamine (21 ml) and dichloromethane (120 ml) and the mixture was stirred at room temperature for 20 hours. The mixture was washed in turn with water and with a dilute aqueous sodium carbonate solution. The organic solution was filtered through phase separating paper and evaporated to give tert-butyl (3R)-3-methyl-4-(p-toluenesulphonyloxy)butyrate as an oil (20 g): NMR(CDCl3) δ 7.6(2H,d), 7.33(2H,d), 3.92(2H,d), 2.45(3H,s), 2.18-2.47(2H,m), 2.0-2.15(1H,m), 1.42(9H,s), 0.95(3H,d).

Provenance & Evidence