Nitrene-transfer agents

The use of sulfonylimino(aryl)iodanes, especially [(tosylimino)iodo]benzene (41), as nitrene-transfer agents has undergone considerable development during the past decade. Much of this effort is based on the finding in the early 1990s that tosylaziridinations of alkenes with Phi = NTs, previously demonstrated with Mn(III)- and Fe(III)-porphyrin catalysts, can be achieved more generally and efficiently with copper(I) and copper(II) salts i.e., the Evans aziridination reaction [172,173]. Standard conditions for preparative aziridinations of this type were developed, and applied to cyclic and acyclic alkenes, arylalkenes, and a, / -... 

Nitrenes, which are monovalent nitrogen species, are unstable but are useful reactive intermediates in organic chemistry. We ll encounter them again in Sections 7.11 and 7.15 in the form of iodine- and bromine-based nitrene transfer agents. 

These iodonium ylides function as carbene and nitrene transfer agents. Carbene transfer typically requires a transition-metal catalyst. A few uncatalyzed reactions, however, have been documented, such as the following remarkably stereospecific transformations of (Z)-and ( )-hept-3-ene ... 

Interaction of trifluoromethanesulfonamide (also known as triflamide or triflylamide, TfNH2) with aryl(difluoro)-2 -bromanes leads to triflylimido-A -bromanes, ArBrNTf, which act as potent nitrene transfer agents. 

Nitrene Transfer. This inner salt can serve as a nitrene transfer agent. In the presence of a gold catalyst, the nitrene moiety is transferred to an activated alkyne, such as iV-(l-alkynyl)oxa-zolidinone, to afford an a, 8-unsaturated amidine in moderate yield (eq4). ... 

More recent work 8> shows that the S—N bond can be cleaved by hydroperoxides and that aromatic sulphonyl azides only undergo free radical thermal decomposition if a source of radicals is provided. Some light on the nature of the radical transfer agent has recently been shed by the observation 14> that dodecyl azides are formed (2.3%) in the thermolysis of mesitylene-2-sulphonyl azide (3) at 150 °C in w-dodecane under nitrogen. It seems likely that a dodecyl radical is produced by hydrogen abstraction by the triplet nitrene (5) [mesitylene-2-sulphonamide was also formed (1.1%)] which then attacks undecomposed sulphonyl azide... 

Fig. 5.8 Examples of polymers grafted from nanocarbons, (a) An ATRP initiator covalently attached to RGO via nitrene and carbodiimide chemistry was used for the growth of poly(2-(ethyl (phenyl)amino)ethyl-methacrylate). (b) A RAFT chain transfer agent is covalently attached to GO prior to polymerization of vinylcarbozole.

As discussed above, iodosylbenzene (Phl=0) oxidizes various transition-metal ions (Mn+) such as manganese, iron, ruthenium, and chromium ions to the corresponding oxo-metal species (0=Mtransfer agents. Likewise, fM-(p-toluenesulfonyl)imino]-phenyliodinane(PhI=NTs) also oxidizes these metal ions to give the corresponding tosylimino-metal species (TsN=M(n+2)+) that undergo nitrene-transfer reaction such as aziridination (Scheme 6B.28) [73],... 

Aziridines can also be prepared by addition of nitrenes to alkenes, or by the use of nitrogen-transfer agents analogons to epoxidising agents. ... 

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