Nitrenes imides

Another quinoxaline-yielding rearrangement, reported by Hanaineh-Abdelnour and coworkers, entailed treating imides 182 with sodium azide to produce quinoxalines 183 in moderate to good yields <99H2931, 99T11859>. The reaction presumably proceeds by a nitrene insertion to close the pyrazine ring. 

Besides commonly used TsN=IPh, TsNs can also be employed as a nitrene source. Bach and Korber have recently reported an Fe(iii)-catalyzed imidation of allyl sulfides 200 with iV-/ //-butyloxycarbonyl azide (BocNs), followed by [2,3]-sigmatropic rearrangement (Scheme 21). " The azide reacts with FeCl2 to generate Fe(iv) nitrene complex 201, which then reacts with allyl sulfide 200, to give an intermediate sulfimide 203, presumably through Fe(iii) intermediate 202. 

Af-(/ -Tolylsulfonyl)imino]phenyliodinane, PhI=NTs, is a well-known nitrene precursor.69 It has now been used to imidate aldehydes (i.e. RCH=0 RCH=NTs) using a ruthenium(II) catalyst and triphenylphosphine. Ph3P=NTs formation is proposed to occur, followed by aza-Wittig reaction. 

RHENIUM(VI) COMPOUNDS 43.8.1 Nitrides, Imides (Nitrenes) and Amides... 

Anionic N-donor ligands comprise essentially amido (NR2 ), imides or nitrenes (NR ) amidinates or guanidinates... 

The oxidation of amines, acylhydrazines, and alkoxy amines described in this section involves the formation of nitrenes or other intermediates, depending on the nature of the nitrogen substituent and the oxidant, although lead tetraacetate is commonly employed. For example, a nitrenium ion or an amino lead derivative was proposed as the intermediate in the oxidation of alkoxyamines with lead tetraacetate 2. However, evidence has been provided that the jV-acetoxy species is the intermediate in the aziridination of alkenes with V-aminophthal-imide and /V-aminoquinazolinone, where a mechanism analogous to the Bartlett mechanism for the peracid epoxidation of alkenes should be operating3,4. 

NH NF12, azanylidene, hydridonitrogen(2 ) nitrene >NF1, azanediyl =NF1, azanylidene imino NH+, azanyliumdiyl, hydridonitrogen( 1 +) NH2+, azanebis(ylium), hydridonitrogen(2+) NH-, azanidyl, hydridonitrate(l—) NH2-, azanediide, hydridonitrate(2—) imide —NH-, azanidyl amidyl NH2-, azanediido, hydridonitrato(2—) imido... 

The D-hex-2-ulopyranosyl azides (327) lose nitrogen on photolysis and are converted to a mixture of two labile imidates. The intermediate nitrenes rearrange by either C2-C3 cleavage (major pathway) or C1-C2 cleavage (minor pathway) followed by carbon-nitrogen bond formation to yield the imidates (328) and (329) respectively, irrespective of the anomeric configuration of the azides studied. The E,E, E,Z- and Z,Z-isomers of 2,6-di(4 -azidobenzylidene)cyclohexanone do not interconvert on irradiation either in the crystalline state or when adsorbed on silica gel but decompose to yield nitrene-derived products. The main decomposition products of the azides of terephthalic and isophthalic acids are reported... 

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