[C:1]1(=O)[CH2:6][CH2:5][CH2:4][CH2:3][CH2:2]1.[C:8]([S@@:12]([NH2:14])=[O:13])([CH3:11])([CH3:10])[CH3:9].C(=O)(O)[O-].[Na+]>C1COCC1.[O-]CC.[O-]CC.[O-]CC.[O-]CC.[Ti+4]>[C:1]1(=[N:14][S:12]([C:8]([CH3:11])([CH3:10])[CH3:9])=[O:13])[CH2:6][CH2:5][CH2:4][CH2:3][CH2:2]1Titanium tetraethoxide (2 eq, 3.56 mL, d 1.088) was added to a solution of cyclohexanone (1.2 eq, 1.0 g, 1.05 mL, d 0.947) in 20 mL of dry THF under nitrogen atmosphere. After 5 min, (S)-t-butanesulfinamide (1200-A, 1.028 g) in 10 mL of THF was added dropwise. The mixture was heated to 60° C. overnight. The reaction mixture was poured into an equal volume of aqueous saturated sodium bicarbonate solution with rapid stirring and immediately filtered through celite. The filter cake was washed with ethyl acetate (50 mL). The layers in the filtrate were separated and the aqueous layer was extracted with ethyl acetate (30 mL). The combined organic layers were dried over magnesium sulfate, filtered and concentrated. The residue was chromatographed on silica gel (gradient:ether/hexanes; 1:9 to 1.1) to afford the product 1200-B (1.3 g; 76%) as a colorless oil. The product was kept under inert atmosphere at −20° C.
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