Ethyl formate → Sodium1-ethoxy-1,3-dioxopropan-2-ide

To a mixture of sodium hydride, 60% (1.07 g, 26.7 mmol) and iPr2O (40 mL) at RT was added ethyl acetate (2.36 ml, 24.1 mmol) in one portion. The internal temperature was adjusted to 40° C. After 5 minutes, ethyl formate (3.87 ml, 48.1 mmol) was added dropwise such that the internal temperature did not rise above 42° C. After the addition was complete, the solution was stirred at RT for 16 hr. The mixture was filtered under Argon and the solid rinsed with hexanes. The resulting white solid, sodium (Z)-3-ethoxy-3-oxoprop-1-en-1-olate, was advanced without further purification.