Diethyl methylphosphonate → Diethyl(4-(cyclopropanesulfonamido)bicyclo[2.2.2]octan-1-yl)methylphosphonate

Participants

Reaction Conditions

Reaction Steps

A solution of diethyl methylphosphonate (1.27 g, 8.36 mmol) was dissolved in THF (20 mL) and cooled to about −78° C. in a dry ice-acetone bath under nitrogen. Then n-BuLi (9.77 mmol, 3.9 mL, 2.5M in hexane) was added dropwise over about 5 min. The reaction mixture was stirred for about 3 h, keeping the temperature below about −70° C. Then a solution of methyl 4-(cyclopropanesulfonamido)bicyclo[2.2.2]octane-1-carboxylate (800 mg, 2.79 mmol) in THF (10 mL) was added, keeping the temperature at about −78° C. The solution was stirred for about 15 h, allowing the temperature to rise slowly to rt. To the reaction mixture was added saturated aqueous NH4Cl (30 mL) and extracted with EtOAc (3×30 mL). The organic layers were combined and washed with brine, dried over anhydrous Na2SO4 and concd to provide diethyl(4-(cyclopropanesulfonamido)bicyclo[2.2.2]octan-1-yl)methylphosphonate (1.30 g, 100% yield). The crude product was used in next step without further purification. LC/MS (Table 1, Method p) Rt=1.62 min; MS m/z: 408 (M+H)+.

Provenance & Evidence