Triphenylphosphine → 2-Bromo-5-[3-{[tert-butyl(dimethyl)silyl]oxy}-2-({[tert-butyl(dimethyl)silyl]oxy}methyl)propoxy]pyridine

Participants

Reaction Conditions

Reaction Steps

Diethylazodicarboxylate (3.445 mL, 22.2 mmol) was added dropwise to a stirred mixture of 3-{[tert-butyl(dimethyl)silyl]oxy}-2-({[tert-butyl(dimethyl)silyl]oxy}methyl)-1-propanol (184) (reported by Kim et al., 2001, via silylation and hydroboration of 2-methylene-1,3-propanediol) (5.706 g, 17.1 mmol), 6-bromo-3-pyridinol (3.571 g, 20.5 mmol) and triphenylphosphine (5.386 g, 20.5 mmol) in anhydrous THF (55 mL) at 0° C. under N2. After stirring at 0° C. for 1 h, and then at room temperature for 41 h, the mixture was concentrated under reduced pressure and the residue was chromatographed on silica gel. Elution with 0-5% Et2O/petroleum ether firstly gave foreruns, and then further elution with 5% Et2O/petroleum ether gave 2-bromo-5-[3-{[tert-butyl(dimethyl)silyl]oxy}-2-({[tert-butyl(dimethyl)silyl]oxy}methyl)propoxy]pyridine (185) (8.09 g, 97%) as a colourless oil; 1H NMR (CDCl3) δ 8.06 (d, J=3.0 Hz, 1H), 7.35 (dd, J=8.7, 0.3 Hz, 1H), 7.11 (dd, J=8.7, 3.2 Hz, 1H), 4.03 (d, J=5.9 Hz, 2H), 3.73 (dd, J=10.1, 5.7 Hz, 1H), 3.69 (dd, J=10.0, 6.0 Hz, 1H), 2.16 (sept, J=5.8 Hz, 1H), 0.88 (s, 18H), 0.03 (2 s, 12H); HRESIMS calcd for C21H41BrNO3Si2 m/z [M+H]+ 492.1783, 490.1803. found 492.1786, 490.1804.

Provenance & Evidence