Azodicarboxylate acyclic

Acyclic ADC compounds, which are more correctly named as derivatives of diazene, are generally prepared from hydrazine derivatives. For example, diethyl azodicarboxylate (Chemical Abstracts name diethyl diazene-1,2-dicarboxylate)5 is prepared from hydrazine by treatment with ethyl chloro-formate followed by oxidation with chlorine in benzene-water.6 Other oxidants which have been used include JV-bromosuccinimide,7 nitric acid,8 inorganic nitrates,9 potassium dichromate,10 silver carbonate on celite,11 and phenyl iodosotrifluoroacetate.12 The hydrazine derivative may also be... 

The chemistry of chiral 1,3-dithiane 1-oxides, in particular their use as chiral auxiliaries, has been reviewed <19980PP145>. Some further developments in this field are the stereoselective a-alkylation with alkyl halides <1997T13149> or a-hydrazination with di-fert-butyl azodicarboxylate (DBAD) <2000T9683>. The carbonyl group of 2-acyl-l,3-dithiane 1-oxides was also used as an electrophile (Scheme 82). Interestingly, acyclic enolates react with these substrates to give a 95 5 mixture of anti- and ry -adduct, whereas cyclic enolates produce a mixture of anti- and ry -adduct in 8 92 ratio <2000JOC6027>. 

The stereoselective normal electron demand Diels-Alder reaction of chiral 13-diaza-13-butadienes 42, derived from acyclic carbohydrates, with diethyl azodicarboxylate 2 yields the corresponding functionalized l,23,6-tetrahydro-133,4-tetrazines 43. The observed stereoselectivity is markedly dependent on the relative stereochemistry at C-1 3 - Reactions proceed slowly in benzene solution at room temperature, but are greatly accelerated by microwave irradiation <99JOC6297>. 

Hydrogenated derivatives of this system have been prepared from acyclic enyne precursors (Scheme 75) by ringclosing metathesis, followed by [4-1-2] cycloaddition of the resulting diene with diethyl azodicarboxylate <2003S2017>. 

Both cyclic and acyclic R-N = N — R systems undergo ene reactions with simple alkenes, and most studies have employed either A -substituted triazolinediones 1 or azodicarboxylate diesters 3 to produce the triazolidines 2 and the hydrazines 4, respectively. 

Enol Amination. The Cu[(S,5)-t-Bu-box] (OTf)2 complex was found to be optimal for promoting the enantioselective conjugated addition of enolsilanes to azodicarboxylate derivatives (eq 13). This methodology provides an enantioselective catalytic route to differentially protected ot-hydrazino carbonyl compounds. Isomerically pure enolsilanes of aryl ketones, acylpyrroles, and thioesters add to the azo-imide in greater than 95% ee. The use of an alcohol additive was critical to achieve catalyst turnover. Amination of cyclic enolsilanes was also possible. For example, the enolsilane of 2-methylindanone provides the adduct containing a tetrasubstituted stereogenic center in 96% ee and high yield. Acyclic (Z)-enolsilanes react in the presence of a protic additive with enantioselection up to 99%. ... 

Aza-l-thia-1,3-butadiene, 232-233 1-Azirine, 57-59 Azirine, 232, 257 Azo compound, 154-163 Azoalkene, 267-270 cyclic, 156 Azobenzene, 156 Azodicarboxylate, 202, 269-271 acyclic, 154-156 cyclic, 156-160 ester, 154... 

The stereoselective normal electron-demand Diels-Alder reactions of chiral 1,2-diaza-1,3-butadienes, derived from acyclic carbohydrates of different configuration, with diethyl azodicarboxylate (DEAD) are impractical at room temperature. In contrast, these are completed within a few hours by use of a focused microwave reactor. 

Diethyl azodicarboxylate will participate in the ene reaction with both cyclo-nona-l,2-dienes and acyclic allenes to give the corresponding 2-ylbicarbamate-1,3-dienes under mild conditions and in good yields. A study of the reactivity of diene (37) with activated olefins indicates that the percentage of ene adduct (38) over the Diels-Alder product (39) increases with a more highly substituted olefin. ... 

Isocupreidine ((3-ICD, 19), another compound in the cinchona alkaloid family, can also catalyze the a-amination of 1,3-dicarbonyl compounds enantioselectively [37]. The reaction of a-substituted 1,3-dicarbonyl compounds, including cyclic and acyclic (3-ketoesters and 1,3-diketones with di-tert-butyl azodicarboxylate, proceeded with high yield and enantioselectivity. 

Amination of a-cyanoketones by di-/cr/-butyl-azodicarboxylate has also been investigated. The thiourea catalyst 21 (1-10 mol%, toluene, 78 C to rt, 0.5 h-8 d) was found to give the best results. Various cyclic (five- and six-membered ring) and acyclic cyanoketones were excellent substrates for this reaction (14 examples, 45-95% yield, 87-99% ee) [47]. 

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