Diethyl chlorophosphate → HCID 10520788, compound

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Reaction Steps

Potassium tert-butoxide (1.0M in THF, 24.1 ml) is added to a mixture of 1-(tert-butyl)-tetrahydroquinoxalin-2,3-dione (XXXI, 5.00 g) and THF (54.0 ml) at -20°. The mixture is allowed to warm to 0° over 30 min. After cooling to 40°, diethyl chlorophosphate (3.53 ml) is added and the solution is allowed to warm to 20°-25° over 40 min. After cooling to -78°, a solution of 4-fluorobenzyl isocyanide (3.62 g) and THF (5.0 ml) is added. Potassium tert-butoxide (24.1 ml) is then added dropwise over several min. The mixture is stirred at -78° for 30 rain and is allowed to warm slowly to 20°-25° over 2 hr. Aqueous workup (ethyl acetate, magnesium sulfate) and purification by flash chromatography eluting with ethyl acetate/hexane (1/2), pooling the appropriate fractions and concentration gives the title compound,

Provenance & Evidence