Nitrogen transfer reagent

This methodology is also an important and potentially valuable method for C—N bond formation using the amination of carbon nucleophiles with electrophilic nitrogen transfer reagents (Scheme 1) Amination of ordinary carbanions and a-carbanion derived from carbonyl compounds and nitriles provides an important method for the synthesis of amines and a-amino carbonyl compounds and nitriles", respectively. For this purpose, a number of electrophilic amination reagents, which are synthetic equivalents of the R2N+ synthon, have been developed and the synthetic potential of electrophilic amination of carbon nucleophiles has been studied in detail . ... 

On the other hand, for allylic aminations very promising results have been realized with regard to regioselectivity, catalytic activity and substrate scope. However, further efforts are necessary to find nitrogen transfer reagents which allow convenient deprotection and isolation of the allylic amine. 

A number of nitrido manganese complexes have been reported. Most of these complexes are Mnv, with only one example reported for Mnvn. These complexes typically incorporate polydentate ligands thus, no examples could be found of simple halide or alkoxide nitrido manganese complexes. Since the original disclosure by Groves and co-workers that these could be utilized as nitrogen transfer reagents, they have received considerable attention [48,49]. ... 

Since a chiral nitride complex is considered to be a good candidate for an asymmetric nitrogen transfer reagent, the intention of the authors group was to apply some complexes to asymmetric organic synthesis [22]. 

The chiral nitridomanganese complex 545 represents a novel self-contained asymmetric nitrogen-transfer reagent which has been used to convert alkenes to scalemic aziridines directly, although a stoichiometric amount of transfer reagent is required. This protocol makes use of A -2-(trimethylsilyl)ethanesulfonyl chloride (SESCl) (546) as an activator, providing A -SES-aziridines 547 that are easily deprotected under mild conditions using... 

Significantly increased ee values were obtained by using the new chiral PTCs 31 and 32, which can be easily prepared starting from 2-hydroxy-3-chloromethyl-5-methyl benzaldehyde and cinchonine or cinchonidine, respectively [30]. By using 31 or 32, up to 95% ee was achieved in the reaction of electron-deficient olefins with N-acyl-N-arylhydroxylamines as nitrogen transfer reagents under biphasic conditions (toluene/aqueous NaOH) at room temperature (Scheme 5.24). 

With a few exceptions [55], sulfoxides themselves have not been used as ligands in asymmetric catalysis so far. However, their sulfur atom can easily be oxidized further to give the corresponding sulfoximines. With appropriate substrates and mesitylenesulfonylhydroxylimine (MSH) as nitrogen-transfer reagent this reaction proceeds in a stereospecific manner [45,56,57]. In contrast to sulfoxides, optically active sulfoximines have found wide application in asymmetric catalyt-... 

A number of approaches have been tried for modified halo-de-diazoniations using l-aryl-3,3-dialkyltriazenes, which form diazonium ions in an acid-catalyzed hydrolysis (see Sec. 13.4). Treatment of such triazenes with trimethylsilyl halides in acetonitrile at 60 °C resulted in the rapid evolution of nitrogen and in the formation of aryl halides (Ku and Barrio, 1981) without an electron transfer reagent or another catalyst. Yields with silyl bromide and with silyl iodide were 60-95%. The authors explain the reaction as shown in (Scheme 10-30). The formation of the intermediate is indicated by higher yields if electron-withdrawing substituents (X = CN, COCH3) are present. In the opinion of the present author, it is likely that the dissociation of this intermediate is not a concerted reaction, but that the dissociation of the A-aryl bond to form an aryl cation is followed by the addition of the halide. The reaction is therefore mechanistically not related to the homolytic halo-de-diazoniations. 

Halotriazoles can act as halogenating agents and A-acyltriazoles can act as acyl transfer reagents. Triazole can be used for the synthesis of peptide bonds and is superior to imidazole in that less racemization is observed. It can also be used to transfer the t-butyloxycarbonyl (t-Boc) protecting group to the nitrogen of amino acids. For details see Polya <84CHEC-I(5)733, p. 786). 

The use of Chloramine-T or Bromamine-T as the nitrogen source has been useful as the transfer reagent in the aziridination reaction. Bedekar and co-workers have found that simple cyclic olefins such as norbornene, cyclohexene, or cyclooctene produce low yields of aziridinated products. However, the same reaction run in a simple microwave oven increases the chemical yield dramatically <2001JOC30>. The reaction shown in Equation (13) was run without the assistance of microwave energy and provided approximately half of the chemical yield at 38%. 

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