Br[C:2]1[O:3][C:4]([CH3:7])=[N:5][N:6]=1.C([Mg]Cl)(C)C.[CH:13]1([CH2:16]/[C:17](=[N:19]\[S:20]([C:22]([CH3:25])([CH3:24])[CH3:23])=[O:21])/[CH3:18])[CH2:15][CH2:14]1.C[Al](C)C.CCCCCCC>C1COCC1.C1(C)C=CC=CC=1>[CH:13]1([CH2:16][C:17]([NH:19][S:20]([C:22]([CH3:23])([CH3:25])[CH3:24])=[O:21])([CH3:18])[C:2]2[O:3][C:4]([CH3:7])=[N:5][N:6]=2)[CH2:14][CH2:15]1
To a solution of 2-bromo-5-methyl-1,3,4-oxadiazole (CAN 864750-58-3, 0.5 g, 3.07 mmol) in dry THF (8 ml) cooled down to −15° C. under an argon atmosphere was added isopropyl magnesium chloride, lithium chloride complex (2.36 ml, 3.07 mmol). (During the addition the temperature was kept below −12° C.). The reaction was then stirred at −15° C. for 30 minutes followed by slow addition of a solution of (Z)—N-(1-cyclopropylpropan-2-ylidene)-2-methylpropane-2-sulfinamide (CAN 1426426-70-1, 618 mg, 3.07 mmol) and a 2M solution of trimethylaluminum in heptane (1.53 ml, 3.07 mmol) in dry toluene (8 ml). The reaction was allowed to warm up to room temperature overnight. The reaction was cooled down to 0° C. and quenched by addition of water (slow addition because reaction very exothermic). The reaction medium was diluted with ethylacetate and the organic phase was extracted with a saturated aqueous solution of ammonium chloride. The organic phase was collected and the aqueous phase was back-extracted with ethylacetate. The combined organic phases were dried over sodium sulfate and evaporated down to dryness. The crude material was purified by flash chromatography on silica eluting with a dichloromethane/methanol gradient to yield the title compound (521 mg, purity: 90%, 54%). MS (ESI, m/z): 286.5 (M+H+).
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