Dimethyl methylphosphonate → Dimethyl 2-oxohept-6-ynylphosphonate

Participants

Reaction Steps

To a solution of dimethyl methylphosphonate (2.16 mL, 20 mmol) in anhydrous THF (30 mL), cooled at −78° C. was added n-BuLi (1.6 M in hexane, 13.75 mL, 22 mmol). The mixture was stirred for 30 minutes at this temperature under nitrogen. Methyl hexynoate (1.26 g, 10 mmol) was added dropwise for 10 minutes. The mixture was stirred for 2 hours at −78° C., gradually was warm to room temperature. The mixture was quenched with addition of 1N HCl to pH 4-5. The organic layer was separated, washed with brine and dried over MgSO4. The residue was purified through flash chromatography on silica gel (MeOH:CH2Cl2=2:98) to give the product (370 mg) with colorless oil in 17% yield. 1HNMR (CDCl3, ppm) δ 1.80 (t, J=7.0 Hz, 2H), 1.95 (s, 1H), 2.24 (dt, J=2.9 and 7.0 Hz, 2H), 2.73 (t, J=7.0 Hz, 2H), 3.06 (d, J=22.7 Hz, 2H), 3.77 (s, 3H), 3.70 (s, 3H).

Provenance & Evidence