Ethyl chloroformate → Ethyl 4-({[(1,1-dimethylethyl)(dimethyl)silyl]oxy}methyl)-1-({[2-(trimethylsilyl)ethyl]oxy}methyl)-1H-imidazole-2-carboxylate

Participants

Reaction Conditions

Reaction Steps

nBuLi (2.2 mL of a 1.9M solution in hexanes, 4.2 mmol) was added dropwise to a −78° C. solution of 4-({[(1,1-dimethylethyl)(dimethyl)silyl]oxy}methyl)-1-({[2-(trimethylsilyl)ethyl]oxy}methyl)-1H-imidazole (1.20 g, 3.5 mmol) in THF (10 mL). The reaction mixture was stirred at −60° C. for 2 h, cooled to −78° C. and ethyl chloroformate (0.70 mL, 7.3 mmol) was added dropwise. The solution was allowed to warm to RT, quenched by addition of sat'd NaHCO3 and extracted with CH2Cl2. The organic phase was dried (Na2SO4), filtered, and purified by silica gel chromatography (0-50% EtOAc/hex) to afford the title compound (1.21 g, 83%) as a light brown oil and as a mixture of the expected two isomers. Major isomer: 1H NMR (400 MHz, CHLOROFORM-d) δ ppm 7.05 (s, 1H), 5.90 (s, 2H), 4.75 (s, 2H), 4.34-4.43 (m, 2H) 3.48-3.58 (m, 2H) 1.40 (t, J=7.15 Hz, 3H), 0.91-0.89 (m, 2H), 0.87 (s, 9H), 0.06 (s, 6H), −0.06 (s, 9H).

Provenance & Evidence