Ferf-butyl azodicarboxylate

The general conclusion to be drawn from the experience reported with these various oxidative methods is that with increasing reactivity of the oxidizing agents more side reactions are to be expected at sensitive amino acid residues, in particular at Met, Trp, and Tyr. In this context, the azodicarboxylic acid derivatives could represent a valid alternative 54,55 since these reagents are devoid of any side reaction at these sensitive residues 56 The reaction of di-ferf-butyl azodicarboxylate (1) with a peptide cysteine thiol leads to the intermediate formation of a sulfenohydrazide adduct 2 that reacts with the second thiol to generate the... 

Electrophilic Amination of Chiral Enolates with Di-ferf-butyl Azodicarboxylate... 

Diphenylphosphinoyl)hydroxylamine (Eq. 137),143 azo esters (Eq. 138),460 and arenesulfonyl azides (Eq. 139)339 have been used to aminate lactam enolates. In the azidation of the lactam 70,461 the diazo compound 73 predominates over azide 72 even though trisyl azide is used as the animating agent amination with di(ferf-butyl) azodicarboxylate was unsuccessful. The closely related lactam 71462 reacts normally with trisyl azide (Eq. 140). 

Axially chiral guanidines with an external guanidine unit such as dinaphthoazepineamidine are effective catalysts for the enantioselective addition of p-oxoesters and a 1,3-diketone to di-ferf-butyl azodicarboxylates to yield cx-hydrazino-p-oxoesters and a-hydrazino-p-dike-tones in 54-99% yields and in 15-98% ee [44]. For example, stirring 2-oxocyclopenta-necarboxylate and di(tert-butyl) azodicarboxylate in THF in the presence of 0.05 mol% catalyst for four hours at —60° C provides an adduct in quantitative yield and in 97% ee (Scheme 4.15). The (R)-catalyst was prepared from (/ )-2,2 -dimethyl-3,3 -binaphthalene-diol ditriflate, 4-methoxyphenylboronic acid and 3.5-di(rert-butyl)phenylboronic acid in six steps. 

In 2004, we reported the Cobalt-catalyzed hydrohydrazination of olefins with di-ferf-butyl azodicarboxylate (5) and phenylsilane (Scheme 4.1). Our approach was based on a stepwise introduction of a hydride and an electrophilic nitrogen source, instead of the more classical approach based on electrophilic activation of the olefin followed by addition of a hydrazine nucleophile. This solution to override the inherently low reactivity of aUcenes was first introduced by Mukaiyama for the related Cobalt-catalyzed hydroperoxidation reaction. The introduction of new Cobalt-catalyst 4 was the key for an efficient hydrohydrazination reaction, as the Cobalt-complexes with acetylacetonate-derived ligands used by Mukaiyama promoted direct reduction of the azodicarboxylate. 

Ac, acetyl AIBN, azobis(isobutanonitrile) All, allyl AR, aryl Bn, benzyl f-BOC, ferf-butoxycarbonyl Bu, Butyl Bz, benzoyl CAN, ceric ammonium nitrate Cbz, benzyloxycarbonyl m-CPBA, m-chloroperoxybenzoic acid DAST, diethylaminosulfur trifluoride DBU, l,8-diazabicyclo[5.4.0]undec-7-ene DCC, /V. /V - d i eye I oh e x y I c ar bo -diimide DCM, dichloromethyl DCMME, dichloromethyl methyl ether DDQ, 2,3-dichloro-5,6-dicyano-l,4-benzoquinone DEAD, diethyl azodicarboxylate l-(+)-DET, L-(+)-diethyl tartrate l-DIPT, L-diisopropyl tartrate d-DIPT, D-diisopropyl tartrate DMAP, 4-dimethylaminopyridine DME, 1,2-dimethoxyethane DMF, /V./V-dimethylformamide DMP, 2,2-dimethoxypropane Et, ethyl Im, imidazole KHMDS, potassium hexamethyldisilazane Me, methyl Me2SO, dimethyl sulfoxide MOM, methoxymethyl MOMC1, methoxymethyl chloride Ms, methylsulfonyl MS, molecular sieves NBS, N-bromosuccinimide NIS, /V-iodosuccinimide NMO, /V-methylmorpho-line N-oxide PCC, pyridinium chlorochromate Ph, phenyl PMB, / -methoxvbenzyl PPTs, pyridiniump-toluenesulfonate i-Pr, isopropyl Py, pyridine rt, room temperature TBAF, tetrabutylammonium fluoride TBS, ferf-butyl dimethylsilyl TBDMSC1, f-butylchlorodimethylsilane Tf, trifhioromethylsulfonyl Tf20, trifluoromethylsulfonic anhydride TFA, trifluoroacetic acid THF, tetrahydrofuran TMS, trimethylsilyl TPAP, tetra-n-propylammonium perruthenate / -TsOH. / -toluenesulfonic acid... 

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