Reaction Steps
Iodobenzene diacetate (6.54 g, 20.29 mmol) was added to (3R)-4-(2-chloro-6-(methylsulfinylmethyl)pyrimidin-4-yl)-3-methylmorpholine (5.88 g, 20.29 mmol), 2,2,2-trifluoroacetamide (4.59 g, 40.58 mmol), magnesium oxide (3.27 g, 81.16 mmol) and rhodium(II) acetate dimer (0.224 g, 0.51 mmol) in DCM (169 ml) under air. The resulting suspension was stirred at RT for 3 days. Further 2,2,2-trifluoroacetamide (1.15 g, 10.15 mmol), magnesium oxide (0.818 g, 20.29 mmol), rhodium(II) acetate dimer (0.056 g, 0.13 mmol) and iodobenzene diacetate (1.64 g, 5.07 mmol) were added and the suspension was stirred at RT for a further 24 hours. The reaction mixture was filtered and silica gel (3 g) was added to the filtrate and then the mixture was evaporated. The resulting powder was purified by flash chromatography on silica, eluting with a gradient of 20 to 50% EtOAc in isohexane. Fractions containing product were evaporated and the residue was triturated with isohexane/methyl tert-butylether to give a solid which was collected by filtration and dried under vacuum to afford N—R{2-chloro-6-[(3R)-3-methylmorpholin-4-yl]pyrimidin-4-yl}methyl)(methyl)oxido-λ6-sulfanylidene]-2,2,2-trifluoroacetamide (6.64 g, 82%); 1H NMR (400 MHz, CDCl3) 1.33 (3H, d), 3.28 (1H, dd), 3.43 (3H, d), 3.46-3.59 (1H, m), 3.62-3.71 (1H, m), 3.79 (1H, d), 3.90-4.50 (2H, br s), 4.21 (1H, s), 4.66 (1H, dd), 4.86 (1H, dd), 6.50 (1H, d); m/z: (ES+) MH+, 401.01, 402.93. b) Sodium hydroxide (Sigma-Aldrich 415413, d=1.515 g/ml, 50 ml of a 50% solution, 937.57 mmol) was added to N-[({2-chloro-6-[(3R)-3-methylmorpholin-4-yl]pyrimidin-4-yl}methyl)(methyl)oxido-λ6-sulfanylidene]-2,2,2-trifluoroacetamide (5.2 g, 12.97 mmol), 1,2-dibromoethane (4.47 ml, 51.90 mmol) and tetrabutylammonium hydrogensulfate (0.441 g, 1.30 mmol) in toluene (500 ml). The resulting mixture was stirred at RT for 24 hours. Further 1,2-dibromoethane (1.00 ml, 11.60 mmol) was added and the mixture was stirred at RT for a further 2 hours. The reaction mixture was diluted with EtOAc (500 ml), and washed sequentially with water (750 ml) and saturated brine (100 ml). The organic layer was dried over MgSO4, filtered and evaporated. The residue was dissolved in DCM (100 ml) and then purified by flash chromatography on silica, eluting with a gradient of 0 to 5% MeOH in DCM. Pure fractions were evaporated to dryness to afford (3R)-4-(2-chloro-6-(1-(S-methylsulfonimidoyl)cyclopropyl)pyrimidin-4-yl)-3-methylmorpholine (1.383 g, 32%); 1H NMR (400 MHz, CDCl3) 1.32 (3H, d), 1.39-1.48 (2H, m), 1.69-1.77 (2H, m), 3.12 (3H, s), 3.22-3.36 (1H, m), 3.54 (1H, td), 3.68 (1H, dd), 3.78 (1H, d), 3.90-4.10 (1H, br s), 4.00 (1H, dd), 4.33 (1H, br s), 6.79 (1H, d); m/z: (ES+) MH+, 331.08, 333.00.
