5-Bromopyridine-2-carbaldehyde → (NE,R)-N-[(5-bromo-2-pyridinyl)methylidene]-2-methylpropane-2-sulfinamide

To a solution of (R)-(+)-2-methyl-2-propanesulfinamide (2.60 g, 21.5 mmol) in 100 mL of CH2Cl2 at room temperature was added CuSO4 (7.53 g, 47.2 mmol) and 5-bromo-pyridine-2-carbaldehyde (4.39 g, 23.6 mmol). The reaction mixture was stirred at room temperature for 21 h and then filtered through Diatomaceous earth, washing with CH2Cl2. The filtrates were concentrated to give a pale brown oil that was purified by flash chromatography on silica gel, eluting with 10-25% EtOAc in hexanes, to afford 6.04 g (97%) of (R)-2-methyl-propane-2-sulfinic acid 1-(5-bromo-pyridin-2-yl)-meth-(E)-ylideneamide as a pale yellow solid.