Phosphine-Free Manganese Catalyst Enables Selective Transfer Hydrogenation of Nitriles to Primary and Secondary Amines Using Ammonia–Borane

ACS Catalysis, Год журнала: 2021, Номер 11(5), С. 2786 - 2794

Опубликована: Фев. 15, 2021

Herein we report the synthesis of primary and secondary amines by nitrile hydrogenation, employing a borrowing hydrogenation strategy. A class phosphine-free manganese(I) complexes bearing sulfur side arms catalyzed reaction under mild conditions, where ammonia–borane is used as source hydrogen. The synthetic protocol chemodivergent, final product either or amine, which can be controlled changing catalyst structure polarity medium. significant advantage this method that operates without externally added base other additives well obviates use high-pressure dihydrogen gas required for reactions. Utilizing method, wide variety symmetric asymmetric were synthesized in high yields. mechanistic study involving kinetic experiments high-level DFT computations revealed both outer-sphere dehydrogenation inner-sphere predominantly operative catalytic cycle.

Язык: Английский

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Advancements in multifunctional manganese complexes for catalytic hydrogen transfer reactions

Chemical Communications, Год журнала: 2021, Номер 57(69), С. 8534 - 8549

Опубликована: Янв. 1, 2021

Manganese catalyzed hydrogen transfer reactions enabled net reductions and cascade CC- CN-bond formation reactions. The success is aided by multifunctional ligand design namely metal–ligand bifunctionality, hemilability, redox non-innocence.

Язык: Английский

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Harnessing alcohols as sustainable reagents for late-stage functionalisation: synthesis of drugs and bio-inspired compounds

Chemical Society Reviews, Год журнала: 2024, Номер 53(9), С. 4607 - 4647

Опубликована: Янв. 1, 2024

This review collectively discussed the utilisation of alcohols in various organic transformations and their application toward intermediates drugs, drug derivatives natural product-like molecules.

Язык: Английский

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Cobalt-Catalyzed Acceptorless Dehydrogenation of Primary Amines to Nitriles

Journal of the American Chemical Society, Год журнала: 2024, Номер 146(17), С. 11801 - 11810

Опубликована: Апрель 16, 2024

The direct double dehydrogenation from primary amines to nitriles without an oxidant or hydrogen acceptor is both intriguing and challenging. In this paper, we describe a non-noble metal catalyst capable of realizing such transformation with high efficiency. A cobalt-centered N,N-bidentate complex was designed employed as metal–ligand cooperative catalyst. Detailed kinetic studies, control experiments, DFT calculations revealed the crucial hydride transfer, proton evolution processes. Finally, tandem outer-sphere/inner-sphere mechanism proposed for through imine intermediate.

Язык: Английский

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Sustainable Alkylation of Unactivated Esters and Amides with Alcohols Enabled by Manganese Catalysis

Organic Letters, Год журнала: 2018, Номер 20(24), С. 7779 - 7783

Опубликована: Дек. 3, 2018

The first example of manganese-catalyzed C-alkylation the carboxylic acid derivatives is reported. bench-stable homogeneous manganese complex enables transformation renewable alcohol and derivative feedstock to higher value esters amides. reaction operates via hydrogen autotransfer ideally produces water as only side product. Importantly, aliphatic-, benzylic-, heterocyclic-containing alcohols can be used alkylating reagents, eliminating need for mutagenic alkyl halides.

Язык: Английский

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A Phosphine-Free Manganese Catalyst Enables Stereoselective Synthesis of (1 + n)-Membered Cycloalkanes from Methyl Ketones and 1,n-Diols

ACS Catalysis, Год журнала: 2020, Номер 10(4), С. 2615 - 2626

Опубликована: Янв. 24, 2020

Herein, we report the stereoselective synthesis of (1 + n)-membered cycloalkane from methyl ketone and 1,n-diol. A manganese(I) complex bearing a phosphine-free ligand catalyzed reaction, which involved formation two C–C bonds via sequence intermolecular- intramolecular-borrowing hydrogenation reactions. It produces 2 mol water as sole byproduct, making process atom economical environmentally benign. Multisubstituted cycloalkanes were obtained in good to excellent yields with very high selectivities. thorough mechanistic analysis by high-level DFT computation rationalizes choice pincer establishes role hemilability for this efficient transformation.

Язык: Английский

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Manganese‐Catalysed Dehydrogenative Coupling – An Overview

Advanced Synthesis & Catalysis, Год журнала: 2020, Номер 362(8), С. 1602 - 1650

Опубликована: Янв. 29, 2020

Abstract Manganese‐catalysed reactions have attracted great attention recently due to the high relative abundance and cheap eco‐friendly behaviour. Applications of manganese catalysis in cross‐dehydrogenative coupling are among hottest areas since 90% contributions very recent. Dehydrogenation alcohols using Mn‐pincer systems is highly explored nowadays for cross‐coupling synthesise a variety products Mn‐catalysed C−H activation, radical applied dehydrogenative couplings various synthons. This review focuses on synthesis synthetically as well biologically important motifs such carbonyl compounds, olefins, nitrogen heterocycles, amines, imines, etc. manganese‐catalysed reactions. magnified image

Язык: Английский

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Manganese‐Catalyzed C−H Olefination Reactions

ChemCatChem, Год журнала: 2019, Номер 11(4), С. 1167 - 1174

Опубликована: Янв. 2, 2019

Abstract Olefins are essential building blocks in organic synthesis, the access to which from simple C−H substrates through catalysis of transition metals, particular earth's abundant ones meets requirements green and sustainable chemistry. Manganese‐catalyzed olefination reactions have emerged as an efficient approach olefins recent years, complementary traditional olefin synthesis. Varieties alkynes, alkenes, allenes well alcohols successfully applied Mn‐catalyzed with substrates, providing multisubstituted bearing varied functional groups. This minireview presents great progresses newly achieved on manganese‐catalyzed reactions.

Язык: Английский

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

ChemCatChem, Год журнала: 2019, Номер 11(10), С. 2500 - 2510

Опубликована: Апрель 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.

Язык: Английский

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Manganese complex-catalysed α-alkylation of ketones with secondary alcohols enables the synthesis of β-branched carbonyl compounds

Chemical Communications, Год журнала: 2020, Номер 56(60), С. 8376 - 8379

Опубликована: Янв. 1, 2020

Herein, β-branched carbonyl compounds were synthesised via the α-alkylation of ketones with secondary alcohols under "borrowing hydrogen" catalysis. A wide range alcohols, including various cyclic, acyclic, symmetrical, and unsymmetrical have been successfully applied developed reaction conditions. manganese(i) complex bearing a phosphine-free multifunctional ligand catalysed produced water as sole byproduct.

Язык: Английский

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