Phosphine Ligand‐Free Ruthenium Complexes as Efficient Catalysts for the Synthesis of Quinolines and Pyridines by Acceptorless Dehydrogenative Coupling Reactions

ChemCatChem, Journal Year: 2019, Volume and Issue: 11(10), P. 2500 - 2510

Published: April 10, 2019

Abstract A series of phosphine‐free Ru(III)/Ru(II) complexes NH functionalized N ˄ pincer ligands exhibit excellent activity for acceptorless dehydrogenative coupling (ADC) secondary alcohols with 2‐aminobenzyl or γ ‐amino to quinolines and pyridines. Ru(III) [LRuCl 3 ] (L=6‐(3‐R 1 ,5‐R 2 ‐1H‐pyrazol‐1‐yl)‐N‐(pyridin‐2‐yl)pyridin‐2‐amine; a : R =R =H (L1); b =Me (L2); c =H, =CF (L3); d =Ph (L4); 1b Me L=6‐(3,5‐dimethyl‐1H‐pyrazol‐1‐yl)‐N‐methyl‐N‐(pyridin‐2‐yl)pyridin‐2‐amine (L2 )) were obtained by refluxing RuCl ⋅ xH O the corresponding ligand in EtOH. Five Ru(II) [LRu(DMSO‐κS)Cl ( L=L1; L=L2; L=L3; L=L4; 2b L=L2 ) formed reducing complex The latter could also be prepared directly Ru(DMSO) 4 Cl These complexes, especially / , exhibited high catalytic efficiency broad functional group tolerance ADC reactions detail mechanistic study indicated was reduced into species, which is active center via Ru−H/N−H bifunctional outer‐sphere mechanism. This protocol provides reliable, atom‐economical environmentally benign procedure C−N C−C bond formation.

Language: Английский

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Ruthenium-Catalyzed Dehydrogenative β-Benzylation of 1,2,3,4-Tetrahydroquinolines with Aryl Aldehydes: Access to Functionalized Quinolines

Organic Letters, Journal Year: 2016, Volume and Issue: 18(13), P. 3174 - 3177

Published: June 14, 2016

A new benzylation protocol, enabling straightforward access to β-benzylated quinolines, has been demonstrated. By employing readily available [RuCl2(p-cymene)]2 as a catalyst and O2 sole green oxidant, various 1,2,3,4-tetrahydroquinolines were efficiently converted in combination with aryl aldehydes into desired products step- atom-economic fashion together the advantages of excellent functional group tolerance chemoselectivity, offering an important basis for transformation saturated N-heterocycles functionalized N-heteroaromatics via dehydrogenative cross-coupling strategy. Mechanistic investigations support that reaction undergoes monodehydrogenation-triggered β-benzylation mode.

Language: Английский

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Borrowing Hydrogen and Acceptorless Dehydrogenative Coupling in the Multicomponent Synthesis of N‐Heterocycles: A Comparison between Base and Noble Metal Catalysis

European Journal of Organic Chemistry, Journal Year: 2021, Volume and Issue: 2021(46), P. 6206 - 6223

Published: Nov. 4, 2021

Abstract Acceptorless dehydrogenative coupling reactions (ADC) and hydrogen transfer strategies (HT) provide a powerful tool in the multicomponent formation of N ‐ heterocycles. A broad variety complex products can be obtained starting from simple, cheap commercially available reagents. The protocols are highly atom‐efficient, as water, dihydrogen, or some cases peroxide, only by‐products. Moreover, neither further reducing oxidizing agents, nor external general required. Especially base metal‐catalyzed become ever more important. Therefore, recent years, various different manganese, iron, cobalt, nickel copper catalysts have been developed. This Minireview highlights progress that has made by using abundant metal complexes to promote cyclizations for heterocycles compares their performance with noble catalyst systems.

Language: Английский

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An annulative transfer hydrogenation strategy enables straightforward access to tetrahydro fused-pyrazine derivatives

Chemical Communications, Journal Year: 2016, Volume and Issue: 52(70), P. 10636 - 10639

Published: Jan. 1, 2016

A ruthenium-catalyzed annulative transfer hydrogenation strategy, enabling straightforward access to tetrahydro fused-pyrazine derivatives from N-heteroaryl diamines and vicinal diols, is demonstrated.

Language: Английский

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Ruthenium-Catalyzed Enantioselective Hydrogenation of Phenanthridine Derivatives

Organic Letters, Journal Year: 2017, Volume and Issue: 19(6), P. 1458 - 1461

Published: March 6, 2017

The first asymmetric hydrogenation of phenanthridines catalyzed by chiral cationic ruthenium diamine complexes has been developed with up to 92% ee and full conversions. choice the counteranion catalyst was found be critical for achieving high enantioselectivity. In addition, obtained 5,6-dihydrophenanthridine could used as a hydride donor organocatalytic transfer hydrogenation.

Language: Английский

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Synthesis of 2‐Alkylaminoquinolines and 1,8‐Naphthyridines by Successive Ruthenium‐Catalyzed Dehydrogenative Annulation and N‐Alkylation Processes

Advanced Synthesis & Catalysis, Journal Year: 2017, Volume and Issue: 359(7), P. 1202 - 1207

Published: Feb. 15, 2017

Abstract A new one‐pot synthetic protocol, enabling the facile access to 2‐alkylaminoquinolines and 1,8‐naphthyridines by successive ruthenium‐catalyzed dehydrogenative annulation N ‐alkylation processes, has been demonstrated. series of 2‐aminoarylmethanols were efficiently converted in combination with different types nitriles alcohols into various desired products moderate excellent yields after isolation. Advantageously, synthesis proceeds high atom‐efficiency, broad substrate scope, operational simplicity, no need for external hydrogen sources less environmentally benign halogenated reagents, thus offering a practical approach these two compounds that are currently difficult prepare conventional methods. magnified image

Language: Английский

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Ruthenium-Catalyzed Enantioselective Hydrogenation of 1,8-Naphthyridine Derivatives

Organic Letters, Journal Year: 2016, Volume and Issue: 18(11), P. 2730 - 2733

Published: May 20, 2016

The first asymmetric hydrogenation of 2,7-disubstituted 1,8-naphthyridines catalyzed by chiral cationic ruthenium diamine complexes has been developed. A wide range 1,8-naphthyridine derivatives were effectively hydrogenated to give 1,2,3,4-tetrahydro-1,8-naphthyridines with up 99% ee and full conversions. method provides a practical facile approach the preparation valuable heterocyclic building blocks useful motifs for new kind P,N-ligand.

Language: Английский

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Ni⁰/Ni^δ+ Synergistic Catalysis on a Nanosized Ni Surface for Simultaneous Formation of C–C and C–N Bonds

ACS Catalysis, Journal Year: 2019, Volume and Issue: 9(12), P. 11438 - 11446

Published: Nov. 5, 2019

Simultaneous formation of C–C/C–N bonds provides insight into the bottom-up synthesis N-heterocycles. This work reports Ni0/Niδ+ synergistic catalysis on surface Ni nanoparticles for highly efficient one-pot bonds, affording 1,2,3,4-tetrahydroquinoline and its derivatives from 2-amino benzyl alcohol ethanol without any addition liquor base or external hydrogen. has been achieved by regulating particle size activating with O2. In dehydrogenation −CH2–OH to −CH═O, C══C C═N via concurrent cross-condensation, transformation C═C/C═N hydrogen transfer, found be rate-determining step. Reducing effectively increases number Niδ+ sites, which accelerates catalytic through between Ni0 sites. The sites can further increased appropriately

Language: Английский

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Porous cross-linked polymer copper and iridium catalyzed the synthesis of quinoxalines and functionalized ketones under solvent-free conditions

Materials Chemistry Frontiers, Journal Year: 2021, Volume and Issue: 5(21), P. 7861 - 7872

Published: Jan. 1, 2021

Two innovative porous cross-linked polymers (PCP–BTA–Ir and PCP–BTA–Cu) exhibited high catalytic activity towards the synthesis quinoxalines.

Language: Английский

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Ru-CNP Complex-Catalyzed Hydrogen Transfer/Annulation Reaction of 2-Nitrobenzylalcohol via an Outer-Sphere Mechanism

The Journal of Organic Chemistry, Journal Year: 2025, Volume and Issue: unknown

Published: April 3, 2025

The development of efficient catalysts plays a central role in advancing chemical reactions. In this study, ruthenium complex modified with N-heterocyclic carbene-imine-phosphine ligand (CNP) was employed to enhance the hydrogen transfer/annulation process 2-nitrobenzyl alcohols various primary or secondary alcohols. NMR and HRMS analyses reaction solution revealed situ formation [fac-RuH(CO)(PPh3)(κ3-CN(H)P)]Cl through transfer hydrogenation imine moiety within CNP under conditions. This species, bifunctional Noyori-type featuring facial coordination CN(H)P ligand, served as key catalytic intermediate. By leveraging outer-sphere mechanism facilitated by [fac-RuH(CO)(PPh3)(κ3-CN(H)P)]Cl, synthesis 75 quinolines from wide range has been achieved yields high 95%.

Language: Английский

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