scholarly journals An unusual stereoretentive 1,3-quaternary carbon shift resulting in an enantioselective RhII-catalyzed formal [4+1]-cycloaddition between diazo compounds and vinyl ketenes

2018 ◽  
Vol 9 (12) ◽  
pp. 3221-3226 ◽  
Author(s):  
Kevin X. Rodriguez ◽  
Tara C. Pilato ◽  
Brandon L. Ashfeld
Keyword(s):  
Diazo Compound ◽  
Ring Expansion ◽  
Diazo Compounds ◽  
Quaternary Carbon

A Rh2(S-TCPTTL)4-catalyzed cyclopropanation of a vinyl ketene with a disubstituted diazo compound initiates a stereorententive, accelerated ring expansion to provide the cycloadduct in good to excellent yields and enantioselectivity.

Catalyst-free synthesis of oxazol-2(3H)-ones from sulfilimines and diazo compounds through a tandem rearrangement/aziridination/ring-expansion reaction

2021 ◽  
Author(s):  
Lina Song ◽  
Xianhai Tian ◽  
Chunyu Han ◽  
Mehran Amanpur ◽  
Frank Rominger ◽  
...  
Keyword(s):  
Drug Development ◽  
Organic Synthesis ◽  
Significant Role ◽  
Ring Expansion ◽  
Diazo Compounds ◽  
Catalyst Free ◽  
Ring Expansion Reaction

Oxazol-2(3H)-ones play a significant role in the fields of organic synthesis and drug development.

CARBONYL AND THIOCARBONYL COMPOUNDS: X. SYNTHETIC EXPERIMENTS WITH COUMARIN-2-THIONE AND BENZOXANTHIONES

1966 ◽  
Vol 44 (9) ◽  
pp. 1075-1081 ◽  
Author(s):  
N. Latif ◽  
I. Fathy
Keyword(s):  
Hydrazine Hydrate ◽  
Diazo Compound ◽  
Diazo Compounds ◽  
Cyclopropane Derivative ◽  
Cyanoacetic Ester

The benzoxanthene ethers Ia–IIb are obtained in good yields by the action of tetrachloro-and tetrabromo-o-benzoquiuone on 1,2- and 3,4-benzoxanthione, respectively. The benzopyran analogues IIIa–IIIb are obtained by the interaction of the corresponding haloquinone and coumarin hydrazone. The latter, which is now readily obtained by the action of hydrazine hydrate on coumarin-2-thione, condenses with thioketones to give coumarin azines. The benzopyran ethers IIIa and IIIb are cleaved by malononitrile, cyanoacetic ester, hydrazine hydrate, phenylhydrazine, and benzoylhydrazine, yielding the unsaturated nitriles (Va–Vb) and the corresponding hydrazones, respectively.1,2-Benzoxanthione reacts with 9-diazoxanthene, diphenyldiazomethane, and diphenylenediazomethane to give the ethylene sulfides VI–VIII, respectively. However, coumarin-2-thione reacts with the diazo compounds in a different manner; it gives the ethylenes X and XI directly, together with the symmetrical thiiranes XII and XIII, in the cases of diphenyldiazomethane and 9-diazoxanthene, respectively, whereas the cyclopropane derivative XIV is produced in the case of diphenylenediazomethane. XIV is also obtained by the photochemical interaction of coumarin itself and the diazo compound.

scholarly journals INTERACTION OF HYDRIDE Σ-COMPLEX OF 5,7-DINITRO-8-HYDROXYQUINOLINE WITH SALTS OF AROMATIC DIAZO COMPOUNDS

2019 ◽  
Vol 62 (11) ◽  
pp. 85-91 ◽  
Author(s):  
Il'ya I. Ustinov ◽  
Nikolay V. Khlytin ◽  
Igor' V. Blokhin ◽  
Irina V. Shakhkel'dyan ◽  
Yuriy M. Atroshchenko ◽  
...  
Keyword(s):  
Diazo Compound ◽  
Coupling Reaction ◽  
Diazo Compounds ◽  
Azo Compounds ◽  
Azo Coupling ◽  
Absorption Bands ◽  
Stretching Vibrations ◽  
Intramolecular Hydrogen ◽  
Yield And Purity ◽  
Mild Acid

Interaction between 5,7-dinitro-8-hydroxyquinoline hydride anionic σ-adduct and chlorides of substituted aryldiazonium in water yielded 5-arylazo-7-nitro-8-hydroxyquinolines, the substitution products of the nitro group at the C-5 σ-adduct position. The direction of the reaction agrees with the quantum-chemical calculations carried out earlier and the GMLA principle, which assumes that the mild acid, which is a diazocathione, will attack the reaction center to which the softest base corresponds, that is, the least negatively charged C-5 carbon atom, in contrast to the C-7 atom. It is shown that the yield of the product increases with the presence of an electron-withdrawing substituent in the diazocomponent. Also in this study, the synthesis of the hydride σ-adduct of 5,7-dinitro-8-hydroxyquinoline was optimized. It was found that the use of pure dimethylacetamide as a solvent, as well as the addition of sodium carbonate, increases the yield and purity of the synthesized σ-adduct. The structure of the obtained compounds was proved by the methods of NMR and IR spectroscopy. In the IR spectra of all synthesized azo compounds, weak absorption bands corresponding to the stretching vibrations of the azogroup (N = N) are fixed in the range of 1400-1465 cm-1, which also indirectly confirms the expected direction of the reaction. Otherwise, the bands of the azogroup vibrations would be shifted to the 1500-1600 cm-1 region as a result of azo-hydrazoic tautomerism. In 1H NMR spectra of synthesized compounds, there is no proton signal of intramolecular hydrogen bond at δ 14-15 ppm, characteristic of the hydrazine form. The proton signals of the arylazo group also confirm the presence of the latter. The use of anionic hydride σ-complexes of dinitroquinoline derivatives as azo-component in the reaction with aromatic diazo compound expands the synthetic possibilities of the azo coupling reaction and allows to obtaine new nitroazoquinolines.

scholarly journals Pd-Catalyzed Dearomative Three-Component Reaction of Bromoarenes with Diazo Compounds and Allylborates

2019 ◽  
Author(s):  
Masaaki Komatsuda ◽  
Hiroki Kato ◽  
Kei Muto ◽  
Junichiro Yamaguchi
Keyword(s):  
Diazo Compound ◽  
Diazo Compounds ◽  
Reaction Conditions ◽  
Three Component Reaction

Acatalytic dearomative three-component reaction of bromoarenes with TMS-diazomethane and allyl borate was developed. The key of this assembling reaction is the use of a diazo compound to generate a Pd-π-benzyl intermediate through a Pd-carbenoid species. This method allowed for a dearomative functionalization using arenes as limiting reagents. Heteroaryl bromides were also applicable to give dearomatized structures under the reaction conditions.

scholarly journals DFT investigation on mechanism of dirhodium tetracarboxylate-catalyzed O-H insertion of diazo compounds with H2O

2010 ◽  
Vol 8 (1) ◽  
pp. 223-228 ◽  
Author(s):  
Zhenfeng Liu ◽  
Jianyong Liu
Keyword(s):  
Dft Calculations ◽  
Nucleophilic Addition ◽  
Diazo Compound ◽  
Experimental Results ◽  
Diazo Compounds ◽  
Reaction Pathways ◽  
Insertion Reaction ◽  
Oxonium Ylides ◽  
Oxonium Ylide ◽  
Very High

AbstractThe mechanism of the dirhodium tetracarboxylate-catalyzed O-H insertion reaction of diazomethane and methyl diazoacetate with H2O has been studied in detail using DFT calculations. The rhodium catalyst and a diazo compound couple to form a rhodiumcarbene complex. Of two reaction pathways of the Rh(II)-carbene complex with H2O, the stepwise pathway is more preferable than the concerted one. Formation of a Rh(II) complex-associated oxonium ylide is an exothermal process, and direct decomposition of the ylide gives a very high barrier. The high barriers for the 1,2-H shift of Rh(II) complex-associated oxonium ylides make the ylides become stable intermediates in both reactions, especially for the reactions in solution. Difficulty in formation of a free oxonium ylide supports experimental results, indicating that the Rh(II) complex-catalyzed nucleophilic addition of a diazo compound proceeds via a Rh(II) complex-associated oxonium ylide rather than via a free oxonium ylide.

Interconversion of Nitrenes, Carbenes, and Nitrile Ylides by Ring Expansion, Ring Opening, Ring Contraction, and Ring Closure: 3-Quinolylnitrene, 2-Quinoxalylcarbene, and 3-Quinolylcarbene

2009 ◽  
Vol 62 (3) ◽  
pp. 275 ◽  
Author(s):  
David Kvaskoff ◽  
Ullrich Mitschke ◽  
Chris Addicott ◽  
Justin Finnerty ◽  
Pawel Bednarek ◽  
...  
Keyword(s):  
Ir Spectra ◽  
Ring Opening ◽  
Density Functional ◽  
Diazo Compound ◽  
Density Functional Theory Calculations ◽  
Ring Expansion ◽  
Uv Spectra ◽  
Ring Closure ◽  
High Yield ◽  
Uv And Ir Spectra

Photolysis of 3-azidoquinoline 6 in an Ar matrix generates 3-quinolylnitrene 7, which is characterized by its electron spin resonance (ESR), UV, and IR spectra in Ar matrices. Nitrene 7 undergoes ring opening to a nitrile ylide 19, also characterized by its UV and IR spectra. A subsequent 1,7-hydrogen shift in the ylide 19 affords 3-(2-isocyanophenyl)ketenimine 20. Matrix photolysis of 1,2,3-triazolo[1,5-c]quinoxaline 26 generates 4-diazomethylquinazoline 27, followed by 4-quinazolylcarbene 28, which is characterized by ESR and IR spectroscopy. Further photolysis of carbene 28 slowly generates ketenimine 20, thus suggesting that ylide 19 is formed initially. Flash vacuum thermolysis (FVT) of both 6 and 26 affords 3-cyanoindole 22 in high yield, thereby indicating that carbene 28 and nitrene 7 enter the same energy surface. Matrix photolysis of 3-quinolyldiazomethane 30 generates 3-quinolylcarbene 31, which on photolysis at >500 nm reacts with N2 to regenerate diazo compound 30. Photolysis of 30 in the presence of CO generates a ketene (34). 3-Quinolylcarbene 31 cyclizes on photolysis at >500 nm to 5-aza-2,3-benzobicyclo[4.1.0]hepta-2,4,7-triene 32. Both 31 and 32 are characterized by their IR and UV spectra. FVT of 30 yields a mixture of 2- and 3-cyanoindenes via a carbene–carbene–nitrene rearrangement 31 → 2-quinolylcarbene 39 → 1-naphthylnitrene 43. The reaction mechanisms are supported by density functional theory calculations of the energies and spectra of all relevant ground and transition state structures at the B3LYP/6–31G* level.

Rhodium-catalysed alkoxylation/acetalization of diazo compounds: one-step synthesis of highly functionalised quaternary carbon centres

2015 ◽  
Vol 51 (77) ◽  
pp. 14505-14508 ◽  
Author(s):  
Jola Pospech ◽  
Alastair J. J. Lennox ◽  
Matthias Beller
Keyword(s):  
Diazo Compounds ◽  
Tandem Reaction ◽  
Quaternary Carbon ◽  
One Step

An intermolecular tandem reaction for the rapid build-up of densely functionalised α-alkoxy-β-oxo-esters has been developed.

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