Triethyl 2-phosphonopropionate → Ethyl 2-(oxetan-3-ylidene)propanoate

Participants

Reaction Steps

To a solution of triethyl 2-phosphonopropionate (800 mg, 3.4 mmol) in anhydrous THF (3 mL) was added potassium tert-butoxide (340 mg, 3.1 mmol). The reaction was stirred for 1 h at RT then oxetan-3-one (CAS-RN 6704-31-0, available from commercial suppliers, 220 mg, 3.1 mmol) was added in a single portion. The reaction was heated at reflux for 20 h then cooled to RT and adsorbed onto silica gel. Purification by automated column chromatography (Biotage SP4) on silica gel (12 g Grace cartridges) eluting with EtOAc: n-heptane (gradient elution, 0% (equil., 5 CV), 0% (5 CV) 0-100% (25CV), 100% (10 CV)) afforded (i) (151 mg, 31%).

Provenance & Evidence