Direct reductive coupling of secondary amides: chemoselective formation of vicinal diamines and vicinal amino alcohols

2015 ◽  
Vol 51 (6) ◽  
pp. 1096-1099 ◽  
Author(s):  
Pei-Qiang Huang ◽  
Qi-Wei Lang ◽  
Ai-E Wang ◽  
Jian-Feng Zheng
Keyword(s):  
Coupling Reaction ◽  
Cross Coupling ◽  
Amino Alcohols ◽  
Reductive Coupling ◽  
Cross Coupling Reaction ◽  
Carbon Radicals ◽  
Direct Generation ◽  
Homocoupling Reaction ◽  
Reductive Homocoupling ◽  
Secondary Amides

We report the first direct and chemoselective reductive homocoupling reaction of secondary amides and cross-coupling reaction of secondary amides with ketones. This method relies on the direct generation of α-amino carbon radicals from amides.

A Novel Reductive Cross-coupling Reaction of 2-nitrobenzoic Hydrazides and Aldehydes or Ketones Promoted by the Low-valence Titanium Reagent: An Access to 2,3,4,5-tetrahydro-1H-1,3,4-benzotriazepine-5-one Derivatives

2005 ◽  
Vol 2005 (9) ◽  
pp. 553-555 ◽  
Author(s):  
Daqing Shi ◽  
Chunling Shi ◽  
Liangce Rong ◽  
Juxian Wang ◽  
Qiya Zhuang ◽  
...  
Keyword(s):  
Elemental Analysis ◽  
Nmr Spectra ◽  
Coupling Reaction ◽  
Cross Coupling ◽  
Reductive Coupling ◽  
Facile Synthesis ◽  
H Nmr ◽  
Cross Coupling Reaction

A short and facile synthesis of a series of 2,3,4,5-tetrahydro-1H-1,3,4-benzotriazepine-5-one derivatives was accomplished in good yields via the intermolecular reductive coupling reaction of 2-nitrobenzoic hydrazides and aldehydes or ketones promoted by the low-valence titanium reagent (TiCl4/Zn system). Structures were established on the basis of elemental analysis, IR and 1H NMR spectra.

Enolboration of conjugated ketones and synthesis of beta-amino alcohols and boronated alpha-amino acids

2003 ◽  
Vol 75 (9) ◽  
pp. 1349-1355 ◽  
Author(s):  
M. Zaidlewicz ◽  
W. Sokól ◽  
A. Wolan ◽  
J. Cytarska ◽  
A. Tafelska-Kaczmarek ◽  
...  
Keyword(s):  
Amino Acids ◽  
Ionic Liquid ◽  
Ionic Liquids ◽  
Reaction Time ◽  
Coupling Reaction ◽  
Cross Coupling ◽  
Amino Alcohols ◽  
Enantioselective Synthesis ◽  
Enantioselective Reduction ◽  
Cross Coupling Reaction

Enolization–aldolization of conjugated ketones, enantioselective synthesis of benzofuryl beta-amino alcohols, and synthesis of p-dihydroxyborylphenylalanine (BPA) and its analogs are described. Aldolization of benzaldehyde with lithium dienolates derived from unhindered conjugated cyclohexenones favored anti- selectivity, whereas syn selectivity was favored for hindered cyclohexenones. Anti-aldols were preferentially formed from dienolborinates derived from conjugated cyklohexenones, however,competing aldolization at the 2-position was observed for hindered ketones. Benzofuryl beta-amino alcohols were prepared using as a key step the enantioselective reduction of the corresponding alpha-bromoacetylbenzofurans with (–)-B- -chlorodiisopinocampheylborane. Ionic liquids were used as solvents for the synthesis of BPA by the Suzuki cross-coupling reaction. The reaction time is short, and a solution of the catalyst in the ionic liquid can be recycled.

scholarly journals Reductive coupling of two aldehydes to unsymmetrical E-alkenes via phosphaalkene and phosphinate intermediates

2018 ◽  
Vol 54 (52) ◽  
pp. 7163-7166 ◽  
Author(s):  
Juri Mai ◽  
Anna I. Arkhypchuk ◽  
Arvind Kumar Gupta ◽  
Sascha Ott
Keyword(s):  
Coupling Reaction ◽  
Cross Coupling ◽  
Reductive Coupling ◽  
Cross Coupling Reaction

Stilbenes with push–pull electronics are directly accessible from an electron-rich and an electron-deficient benzaldehyde in a novel reductive aldehyde cross-coupling reaction.

Identification of a Surprising Boronic Acid Homocoupling Process in Suzuki–Miyaura Cross-Coupling Reactions Utilizing a Hindered Fluorinated Arene

Synlett ◽  
2020 ◽  
Author(s):  
Samantha L. Gargaro ◽  
Bre'Shon Dunson ◽  
Joshua D. Sieber
Keyword(s):  
Boronic Acid ◽  
Good Yield ◽  
Coupling Reaction ◽  
Cross Coupling ◽  
Product Formation ◽  
Coupling Reactions ◽  
Arylboronic Acids ◽  
Cross Coupling Reactions ◽  
Cross Coupling Reaction ◽  
Homocoupling Reaction

AbstractThe Suzuki–Miyaura cross-coupling reaction of 2-bromo-1,3-bis(trifluoromethyl)benzene with arylboronic acids was evaluated and determined to suffer from the formation of large amounts of boronic acid homocoupling products in conjunction with dehalogenation. Homocoupling product formation in this process likely occurs through a rare protonolysis/second transmetalation event rather than by the well-established mechanism requiring the involvement of O2. The scope of this boronic acid homocoupling reaction was investigated and shown to predominate with electron-deficient arylboronic acids. Finally, a good yield of cross-coupling products could be obtained by employing dicyclohexyl(2′,6′-dimethoxybiphenyl-2-yl)phosphine (SPhos) as the ligand.

Ferromagnetic Chain Based on Verdazyl-Nitroxide Diradical

2020 ◽  
Author(s):  
Evgeny Tretyakov ◽  
Svetlana Zhivetyeva ◽  
Pavel Petunin ◽  
Dmitry Gorbunov ◽  
Nina Gritsan ◽  
...  
Keyword(s):  
Coupling Reaction ◽  
Cross Coupling ◽  
Ferromagnetic Coupling ◽  
Nitronyl Nitroxide ◽  
Triplet Ground State ◽  
One Dimensional ◽  
Cross Coupling Reaction ◽  
Palladium Catalyzed ◽  
Ferromagnetic Chain ◽  
High Yields

<p>Verdazyl-nitroxide diradicals were synthesized using the palladium-catalyzed cross-coupling reaction of the corresponding iodoverdazyls with a nitronyl nitroxide-2-ide gold(I) complex with high yields (up to 82%). The synthesized diradicals were found to be highly thermally stable and have a singlet (D<i>E</i><sub>ST</sub> » -64 cm<sup>–1</sup>) or triplet ground state (D<i>E</i><sub>ST</sub> ³ 25 and 100 cm<sup>–1</sup>), depending on which canonical hydrocarbon diradical type they belong to. Upon crystallization, triplet diradicals form unique one-dimensional (1D) spin <i>S</i> = 1 chains of organic diradicals with intrachain ferromagnetic coupling of <i>J</i>′/<i>k</i><sub>B</sub> from 3 to 6 K.</p>

An Iron-Based Catalyst Enables The Enantioconvergent Synthesis of Chiral 1,1-Diarylalkanes Through a Suzuki-Miyaura Cross-Coupling Reaction

2020 ◽  
Author(s):  
Chet Tyrol ◽  
Nang Yone ◽  
Connor Gallin ◽  
Jeffery Byers
Keyword(s):  
Coupling Reaction ◽  
Cross Coupling ◽  
Coupling Reactions ◽  
Radical Intermediates ◽  
Cross Coupling Reactions ◽  
Cross Coupling Reaction ◽  
Boronic Esters ◽  
Carbon Centered Radical ◽  
Iron Based ◽  
High Yields

By using an iron-based catalyst, access to enantioenriched 1,1-diarylakanes was enabled through an enantioselective Suzuki-Miyaura crosscoupling reaction. The combination of a chiral cyanobis(oxazoline) ligand framework and 1,3,5-trimethoxybenzene additive were essential to afford high yields and enantioselectivities in cross-coupling reactions between unactivated aryl boronic esters and a variety of benzylic chlorides, including challenging ortho-substituted benzylic chloride substrates. Mechanistic investigations implicate a stereoconvergent pathway involving carbon-centered radical intermediates.

Ni(0)-Catalyzed α-Allylic Alkylation of Regular Ketones with 1,3-Dienes under pH and Redox-neutral Conditions

2019 ◽  
Author(s):  
Tiantian Chen ◽  
Yang Yang ◽  
Liyu Xie ◽  
Haijian Yang ◽  
Guangbin Dong ◽  
...  
Keyword(s):  
Oxidative Addition ◽  
Coupling Reaction ◽  
Cross Coupling ◽  
Dual Role ◽  
Allylic Alkylation ◽  
Cross Coupling Reaction ◽  
Neutral Conditions

<p>We report a Ni(0)-catalyzed cross coupling reaction between simple ketones and 1,3-dienes. A variety of a-allylic alkylation products were formed in an 1,2-addition manner with excellent regioselectivity. Water was found to significantly accelerate this transformation. A HO-Ni-H species generated from oxidative addition of Ni(0) to H<sub>2</sub>O is proposed to play a “dual role” in activating both the ketone and the diene substrate.</p>

Piperazine as an Inexpensive and Efficient Ligand for Pd-Catalyzed Homocoupling Reactions to Synthesize Bipyridines and Their Analogues

2019 ◽  
Vol 16 (1) ◽  
pp. 173-180
Author(s):  
Mingwei Chen ◽  
Jinyu Hu ◽  
Xiaoli Tang ◽  
Qiming Zhu
Keyword(s):  
Transition Metal ◽  
Oxidation State ◽  
Coupling Reaction ◽  
Aryl Halides ◽  
Metal Species ◽  
Good Substrate ◽  
Active Metal ◽  
Homocoupling Reaction ◽  
Catalytic Cycles ◽  
Reductive Homocoupling

Aim and Objective: The synthesis of bipyridines, especially 2, 2’-bipyridines, remains challenging because the catalytic cycle can be inhibited due to coordination of bipyridine to transition metal. Thus, the development of efficient methods for the synthesis of bipyridines is highly desirable. In the present work, we presented a promising approach for preparation of bipyridines via a Pd-catalyzed reductive homocoupling reaction with simple piperazine as a ligand. Materials and Methods: Simple and inexpensive piperazine was used as a ligand for Pd-catalyzed homocoupling reaction. The combination of Pd(OAc)2 and piperazine in dimethylformamide (DMF) was observed to form an excellent catalyst and efficiently catalyzed the homocoupling of azaarenyl halides, in which DMF was used as the solvent without excess reductants although stoichiometric reductant was generally required to generate the low-oxidation-state active metal species in the catalytic cycles. </P><P> Results: In this case, good to excellent yields of bipyridines and their (hetero) aromatic analogues were obtained in the presence of 2.5 mol% of Pd(OAc)2 and 5 mol% of piperazine, using K3PO4 as a base in DMF at 140°C. Conclusion: According to the results, piperazine as an inexpensive and efficient ligand was used in the Pd(OAc)2-catalyzed homocoupling reaction of heteroaryl and aryl halides. The coupling reaction was operationally simple and displayed good substrate compatibility.

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