Methyl azidoformate

Methyl 3,6-di-fert-butyl-1 //-azepine-1 -carboxylate (8), on heating with one equivalent of methyl azidoformate, yields a separable mixture of 2,6-and 2,8-diazabicyclooctadienes 10 and 11.145 Initial addition of the nitrene to C4-C5 of the azepine ring, followed by a [1,3]-C or [1,3]-N shift in the resulting azahomoazepine 9, accounts for the products. 

Analogous methyl azidoformate forms with norbornene a thermal unstable triazoline.251 The decomposition products are 40% aziridine and 55% imide. Furthermore it has been observed that the rate of nitrogen evolution of the triazoline from methyl azidoformate increases threefold when triglyme and 20-fold when dimethyl sulfoxide are substituted for 1,1-diphenylethane as solvents. This fact supports a betaine intermediate in the thermal decomposition reaction. The triazoline from 2,4-dinitrophenyl azide and norbornene could just be isolated, but from picryl azide only the aziridine was obtained.252-254 Nevertheless, the high negative value of the activation entropy (—33.4 eu) indicates a similar cyclic transition state for both reactions. 

The parent l/f,4//-pyrrolo[3,2-6]pyrrole (10) has been synthesized <84TL5669> (Scheme 23) from l,4-bis(trimethylsilyl)benzene (300) and methyl azidoformate via the azepine intermediate (301)... 

The interaction of 1 with dipolar reagents has led to bridged norcaradienes (Section V.A.3) of varying stability , but with electrophilic C,V-diphenylnitrone ring expanded 123 is formed (Scheme 23) Similarly , reaction with sulphonyl isocyanates provides isoindolinones 124. Simple 1,3-dipoles such as methyl azidoformate and ethyl diazoacetate are without effect on 1, indicating too large an energy gap between the... 

Cycloaddition of phenyl azide (106, R = Ph) with methylenecyclopropanes (105) followed by photolysis of the primary products (107) yielded spiro compounds (108), in which the aziridine ring could easily be cleaved by acids leading to 109 and (equation 22). Alternatively, compound 108 (R = COOMe) was formed directly upon irradiation of methyl azidoformate (106) in the presence of excess 105 ... 

Note, however, that the reaction of methyl azidoformate with the strained olefin norbornene (11 proceeds by a 1,3-cycloaddition to give the unstable triuzoline adduct (2), which decomposes in refluxing toluene to give the aziridine (3,40%) theimide (4, S3%),gndjtyn-2>norbomene-7-methylcurbamBte (5). ... 

Addition of methoxycarbonylnitrene generated photochemically from methyl azidoformate to methylenecyclopropane gave methyl l-azaspiro[2.2]pentane-l-carboxylate 1, which cannot be isomerized to the cyclobutane derivative like the isosteric oxaspiropentanes. " Treatment with acids such as hydrogen chloride or methanesulfonic acid cleaved the aziridine ring and gave l-(chloromethyl)-l-(methoxycarbonylamino)cyclopropane and l-(mesyloxymethyl)-l-(methoxycarbonylamino)cyclopropane. ... 

Methyl azidoformate (1.0 g, 10 mmol) was added to a Vycor tube containing methylenecyclopropane (40 mL). The tube was equipped with a dry ice condenser and placed in an ice bath next to a quartz photochemical immersion finger. The solution was irradiated with a 450-W medium-pressure mercury arc for 3 h. Excess alkene was then removed by trap-to-trap distillation. Distillation of the residue gave 440 mg (35%) of the product bp 48°C/3 Torr. 

Wilde et al. photolyzed methyl azidoformate in rare-gas matrices at 4 K. Methoxyisocyanate, formaldehyde, and isocyanic acid were identified as the photolysis products on the basis of infrared spectroscopy. No ESR observations of triplet carbmethoxynitrene were attempted. 

Iminosulphuranes.—New results have been reported for three preparative routes to iminosulphmanes. Ando et al have shown that under photochemical conditions methyl azidoformate and methyl sulphide will form the sulphidimine (95), but in the presence of a triplet sensitizer only methyl... 

However, the reaction of methyl azidoformate with al-lylic sulfides afforded methyl IV-allyl-lV-methylthiocarbamates (eq 141). i... 

Nitrene-Transfer Reaction. Pd(PhCN)2Cl2 catalyzes the nitrene-transfer reaction of methyl azidoformate with vinyl ethers, affording methyl iV-methoxycarbonylpropionimidate derivatives (eq 137). ... 

---