Ph, R' = (2.18 mmol) in N^ZV-dimethylacetamide (50 mL) instead of benzene. Workup gave 6, R = Ph, R' = H, in 16% yield.Reaction of 2-Phenylazirine with 1:1 CO/H2 Catalyzed by Pd(PPh3)4. A 1:1 carbon monoxide-hydrogen gas mixture was bubbled through a benzene (50 mL) solution containing 5, R = Ph, R' = (0.531 g, 4.54 mmol), and Pd(PPh3)4 (0.58 mmol). Workup in the usual manner (silica gel chromatography) gave 0.15 g (25%) of 6, R = Ph, R' = H, and 0.024 g (4.5%) of 4,5diphenylpyrimidine.Reaction of N-n -Butyl-2-phenylaziridine with CO and Pd(PPh3)4. The heterocycle (0.602 g, 3.44 mmol) and Pd(PPh3)4 (0.403 g, 0.349 mmol) in benzene (50 mL) were stirred under an atmosphere of carbon monoxide at 40 °C for 2 days. Workup gave recovered starting material.Reaction of 4,5-Diphenyl-l,3-diazabicyclo[3.1.0]hex-3-ene (13) with CO and Pd(PPh3)4. Starting material was recovered when a mixture of 4,5-diphenyl-l,3-diazabicyclo[3.1.0]hex-3-ene (0.207 g, 0.884 mmol) and Pd(PPh3)4 (0.117 g, 0.102 mmol) in benzene (50 mL) was exposed to carbon monoxide for 2 days at 40 °C.(Dimethyl acetylenedicarboxylate)bis(triphenylphoephine)palladium-Catalyzed Carbonylation of 2-Phenylazirine (5, R = Ph, R' = ). A benzene (50 mL) solution of 5, R = Ph, R' = (0.510 g, 4.36 mmol), and the palladium catalyst (0.337 g, 0.436 mmol) was stirred overnight at 40 °C under a CO atmosphere. Workup gave 0.20 g (35%) of 6, R = Ph, R' = H.General Procedure for the Pd(dba)2-Catalyzed Carbonylation of Azirines. This reaction was effected in a manner identical with that described for the Pd(PPh3)4 reaction, except for the change in catalyst. The vinyl isocyanate ( 14) can be isolated by distillation19 of the oil obtained after rotary evaporation. The following procedure was used to obtain pure carbamate ester (15): hexane (20-80 mL) was added to the oil, and the solution was filtered. Excess (10-20 mL) methanol was added to the filtrate, and the solution was stirred at room temperature for approximately 2 h. After removal of hexane-methanol (rotary evaporation), the residue was chromatographed on silica gel. The product yields are listed in Table III.Acknowledgment. We are grateful to the Natural Sciences and Engineering Research Council for support of this research. We thank Dr. John Krause and Raj Capoor for recording mass and carbon-13 magnetic resonance spectra, respectively.
