4-Fluorobenzylisocyanide

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: Potassium tert-butoxide (1.0 M 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 min 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, mp 135°-137°; IR (mineral oil) 2953, 2925, 2855, 1668, 1498, 1299 and 751 cm-1 ; NMR (CDCl3) 8.31, 8.22, 7.63, 7.55, 7.05-7.35 and 1.76 δ; MS (m/z) 335, 279. to warm to 0° over 30 min After cooling to -40° to warm to 20°-25° over 40 min After cooling to -78° 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) the appropriate fractions and concentration

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: 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, to warm to 0° over 30 min After cooling to 40° to warm to 20°-25° over 40 min After cooling to -78° 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) the appropriate fractions and concentration

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: 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 min 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, mp 135°-137°; IR (mineral oil) 2953, 2925, 2855, 1668, 1498, 1299 and 751 cm-1 ; NMR (CDCl3) 8.31, 8.22, 7.63, 7.55, 7.05-7.35 and 1.76 δ; MS (m/z) 335, 279. to warm to 0° over 30 min After cooling to -40° to warm to 20°-25° over 40 min After cooling to -78° 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) the appropriate fractions and concentration