Dimethyl Sulfoxide → HCID 86727212, compound

Participants

Reaction Conditions

Reaction Steps

To a solution of DMSO (0.193 g, 2.46 mmol) in anhydrous DCM (10 mL) at −78° C. under N2 was added oxalyl chloride (0.268 g, 2.11 mmol) slowly, and the mixture was stirred at −30° C. for 45 min. The mixture was then cooled at −78° C., and a solution of ((3aR,4R,5R,6R,7aS)-4,5-bis(benzyloxy)-2-(dimethylamino)-3a,4,5,6,7,7a-hexahydrobenzo[d]thiazol-6-yl)methanol (14) (0.330 g, 0.704 mmol) in anhydrous DCM (5 mL) was added slowly. After stirring at −30° C. for 2 h the reaction mixture was cooled back at −78° C., and triethylamine (0.50 g, 5.0 mmol) was added. The mixture was stirred at −30° C. for another 30 min, and then quenched with water (30 mL). The organic layer was collected, and the aqueous was extracted with DCM (3×20 mL). The combined extract was dried over anhydrous Na2SO4. After filtration the solvent was evaporated under reduced pressure to give a sticky pale yellow foam. Under N2 the pale yellow foam was dissolved in anhydrous THF (15 mL), and MeMgBr (1.4 M in THF/toluene, 1.5 mL, 2.1 mmol) was added. After addition the mixture was stirred at room temperature for 1.5 h. The reaction was quenched with saturated aqueous NaHCO3 (20 mL), and then extracted with DCM (3×15 mL). The combined extract was dried over anhydrous Na2SO4. After filtration the solvent was evaporated under reduced pressure, and the residue was purified on silica gel by flash column chromatography (EtOAc), affording mixed 15a & 15b as a sticky pale yellow foam (0.23 g, 74%) with a ratio of 15a:15b=1:3 based on 1H NMR.

Provenance & Evidence