Methyl iodide → (S)-tert-butyl 1-(tert-butyldimethylsilyloxy)pent-4-en-2-yl(methyl)carbamate

Participants

Reaction Conditions

Reaction Steps

To a solution of (S)-tert-butyl 1-(tert-butyldimethylsilyloxy)pent-4-en-2-ylcarbamate (95 g, 0.3 mol) and MeI (46.7 mL, 0.75 mol) in DMF (500 mL) was added sodium hydride (60%, 18 g, 0.45 mol) at 0° C. The reaction was stirred at 0° C. for 3 h and LC-MS showed the reaction was complete. The reaction was quenched with saturated NH4Cl solution and filtered. The filtrate was concentrated to remove most of DMF and the residue was dissolved in EtOAc (1.5 L). The organic layer was washed with water and brine, dried over Na2SO4. The above steps were repeated with another 127 g of (S)-tert-butyl 1-(tert-butyldimethylsilyloxy)pent-4-en-2-ylcarbamate. The organic layers were combined and concentrated. The resulting residue was purified on silica gel column using a mixture of hexanes and EtOAc to give (S)-tert-butyl 1-(tert-butyldimethylsilyloxy)pent-4-en-2-yl(methyl)carbamate (120 g, 40% for 4 steps). LRMS (M+H+) m/z 230.2.

Provenance & Evidence