Academic literature on the topic 'Hydrogen Borrowing Reaction'

A BINAP-Cu system supported by hydrotalcite has been developed and proved to be a highly efficient catalyst for the atom-efficient and green borrowing hydrogen reaction and dehydrogenative cyclization.

A Ru(ii) complex with 2-phosphinophosphinine ligands activated with KO^tBu catalyses the room temperature transfer hydrogenation of acetophenone and the hydrogen-borrowing reaction of MeOH/EtOH to the advanced biofuel isobutanol.

Amine compounds are widely found in natural products, pharmaceuticals and fine chemical products. Therefore, it is of great significance to develop methods for synthesizing amine compounds. Therefore, in recent years, a new method of synthesizing amines has been developed, namely "hydrogen borrowing reaction". This article reviews the alkylation of primary alcohols and amines, the cyclization of amino alcohols to form N-heterocyclic compounds, the reaction of diols and amines to form N-heterocyclic compounds, the reaction of alcohols and sulfonamides, and the reaction of alcohols and amines containing N heteroatoms , Alcohol and ammonia gas and ammonia to produce amine by hydrogen reaction research progress.

La dissertation suivante se focalise sur de nouvelles transformations organiques, à travers des transferts d’hydrogènes, en utilisant des complexes en tenaille Mn(I) et Ru(II). L’objectif principal est l’étude des complexes Mn(I) et Ru(II) et leur réactivité similaire lors des réactions de transferts d’hydrogènes, comprenant les réactions d’échanges d’hydrogènes et réductions. Le chapitre 1 est une introduction générale sur les réactions de transferts d’hydrogènes reportées dans la littérature pour les complexes Mn(I) et leur réactivité similaire à celle des complexes Ru(II), connus pour leur capacité à réaliser des transferts d’hydrogènes. Le chapitre 2 traite de l’utilisation de MeOH comme une source de carbone C1 pour la synthèse de produits de chimie fine, pharmaceutiques et carburants alternatifs. La beta-méthylation sélective des alcools a été conduite avec succès en utilisant MeOH comme source de carbone C1. Différents complexes de ruthénium ont été investigués pour cette transformation et le complexe en tenaille Ru-MACHO-BH s’est révélé être le meilleur en termes de résultats catalytiques. Des études mécanistiques et calculs DFT ont confirmé la voie par transferts d’hydrogènes « Hydrogen Borrowing Reaction » et la coopération métal-ligand sur le centre métallique ruthénium. Le chapitre 3, lui aussi, concerne la beta-methylation sélective des alcools à l’aide de MeOH comme source de carbone C1. Cependant, dans ce chapitre, les complexes étudiés sont des complexes en tenaille, stables à l’air, à base d’un métal abondant : le manganèse. La réactivité des deux complexes Mn(I) et Ru(II) a été comparée. De nombreux complexes de manganèse en tenaille ont été synthétisés et testés pour la beta-methylation sélective des alcools à l’aide de MeOH. Pour cette réaction, le complexe Mn-MACHO-iPr a montré les meilleurs résultats avec d’excellentes sélectivités et de très bons rendements. Le chapitre 4 démontre la formation de cycloalcanes substitués en utilisant des alcools secondaires ou des cétones ainsi que des diols comme réactifs de départ, avec les complexes Ru-MACHO-BH ou Mn-MACHO-iPr comme pré-catalyseurs. L’analyse de ces réactions a mis en évidence la meilleure réactivité du complexe Mn-MACHO-iPr en comparaison avec le complexe Ru-MACHO-BH. Différents cycloalcanes substitués comme des cyclopentanes, des cyclohexanes et des cycloheptanes ont été synthétisés avec ce complexe de manganèse. Des études mécanistiques ont révélé que la réaction procède via transfert d’hydrogène « Hydrogen Borrowing reaction ». Le chapitre 5 concerne la deutération sélective d’alcools primaires et aliphatiques en utilisant D2O comme source de deutérium et le complexe précédemment établi Mn-MACHO-iPr comme catalyseur. Les analyses ont montré la deutération sélective d’alcools benzyliques en position alpha et la deutération d’alcools aliphatiques en position alpha et béta. Le chapitre 6 concerne l’hydrogénation sélective de carbonates cycliques en méthanol et diols correspondants. Différents complexes de manganèse en tenaille ont été synthétisés pour confirmer l’actitivité envers cette transformation. Le complexe stable à l’air Mn-MACHO-iPr a montré la meilleure activité catalytique avec des TON élevés ainsi qu’une très bonne sélectivité concernant la formation de méthanol et diols. Le chapitre 7 traite de la préparation de méthoxy-boranes and boronate-diols via réduction sélective de carbonates organiques cycliques et linéaires, ainsi que du CO2, en utilisant le pinacolborane comme agent réducteur. Un nouveau complexe de manganèse en tenaille synthétisé a été exploré et a révélé une grande efficacité et sélectivité pour cette transformation
The present dissertation focuses on new organic transformations enabled by hydrogen transfer reactions using Mn(I) and Ru(II) pincer complexes. The primary focus deals with the study of Mn(I) and Ru(II) complexes and their similar reactivity in hydrogen transfer reactions which includes hydrogen borrowing and reduction reactions.Chapter 1 is a general introduction of hydrogen-transfer reactions reported for Mn(I) complexes and their similar reactivity with the Ru(II) complexes that are well-established for the hydrogen-transfer reactions.Chapter 2 focuses on the utilization of MeOH as a C1 source for the synthesis of fine chemicals, pharmaceuticals and alternative fuels. The selective beta-methylation of alcohols was achieved using methanol as a C1 source. Various ruthenium complexes were investigated for this transformation and a Ru-MACHO-BH pincer complex revealed the best catalytic results. Mechanistic studies and DFT calculations confirmed that the reaction proceeds via “Hydrogen borrowing pathways” and involved metal-ligand cooperation on the ruthenium metal center.Chapter 3 also deals with the selective beta-methylation of alcohols using methanol as a C1 source. However, in this chapter, earth-abundant and air-stable manganese pincer complexes were investigated. The reactivity of Mn(I) pincer complexes with Ru(II) pincer complexes was compared. Numerous manganese pincer complexes were synthesized and checked for this process where the Mn-MACHO-iPr complex demonstrates the optimum results with high selectivity and high yield to the corresponding desired product. Chapter 4 demonstrates the formation of substituted cycloalkanes using secondary alcohols or ketones and diols as initial substrates employing Mn-MACHO-iPr complex as pre-catalyst. The reaction studies showed that the Mn-MACHO-iPr complex revealed better reactivity in comparison to the Ru-MACHO-BH complex. Various substituted cycloalkane rings such as substituted cyclopentane, cyclohexane, and cycloheptane rings were synthesized employing the Mn-MACHO-iPr complex. Mechanistic studies revealed that the reaction proceeds via “hydrogen borrowing pathways”.Chapter 5 addresses the selective deuteration of primary and aliphatic alcohols using D2O as a deuterium source. The already established Mn-MACHO-iPr complex was investigated for this transformation which showed selective deuterations of benzylic alcohols at the alpha positions and alpha and beta deuteration for aliphatic alcohols.Chapter 6 deals with the selective hydrogenation of cyclic carbonates to the analogous methanol and diols. Several manganese pincer complexes were synthesized to confirm the activity towards this transformation. Air-stable Mn-MACHO-iPr pincer complex showed the best catalytic activity with high turnover numbers and selective preparation to the corresponding methanol and diols.Chapter 7 discusses the preparation of methoxy-borane and boronate-diols via selective reduction of cyclic and linear carbonates and CO2 using pinacolborane as a reducing agent. A newly synthesized manganese pincer complex was explored for this process which revealed the high efficiency and selectivity towards this transformation

特異なルテニウムが触媒する"Borrowing hydrogen"のコンセプトに基づく有機反応を開発した。まず、Ru/JOSIPHOS触媒を用いて、1,2-ジオールとアミンの反応から光学活性β-アミノアルコールを最高99%収率ならびに77% eeで得ることに成功した。本反応は新規であり、その反応機構についても明らかにした。さらに、RuCl2(PPh3)3/DPEphos/K3PO4を組み合わせた触媒を用いることで、アルコールをアルキル化剤に用いるインドールの3位選択的アルキル化反応を達成した。高効率かつ広いタイプの基質に適用できる。
Several novel ruthenium-catalyzed "borrowing hydrogen"-based organic reaction has been developed. For very first time optically active β-amino alcohols can be sinthesized directy by reaction of 1,2-diol and coressponding amine under Ru/JOSIPHOS catalysis in up to 99% yield and 77% ee. Since this reaction is very new, intensive investigation of the reaction mechanism was also carried out. Meanwhile, combination of RuCl2(PPh3)3/DPEphos/K3PO4 was found to be effective catalyst for alkylation of indole with alcohol as an alkylating reagent. This catalysis was highly reactive to give the corresponding alkylated indole in excellent yield for almost all types of indoles and alcohols substrates.
博士(工学)
Doctor of Philosophy in Engineering
同志社大学
Doshisha University

N-Alkylation of amines with alcohols mediated by borrowing hydrogen is a useful synthetic tool for the preparation of functionalised amines. Specifically, alcohols can be temporarily converted into carbonyl compounds by the metal-catalysed removal of hydrogen. The carbonyl compounds are more reactive than the precursor alcohols and can react in situ with amines to give imines. The metal catalyst returns the borrowed hydrogen to the imines, giving the alkylated amines. Chapter 1 outlines the potential for the atom-efficient hydrogen borrowing processes, giving an overview of the main transformations that can be carried out using this interesting methodology. A preliminary investigation of the reaction mechanism gave us useful information for the synthesis of more robust catalysts for these processes. As a result, a new family of rhodium and iridium complexes was synthesised, which contained a modified Cp* ligand bearing an amine on the tethered chain. Two iridium catalysts were found to be the most active among our family of monomeric complexes. More than 20 substrates containing aryl, heteroaryl and alkyl groups were prepared in 62-99% yields; among them, primary and secondary alcohols and primary and secondary amines have been used. Furthermore, a broad range of functional groups were tolerated, such as halides, nitriles, ethers, esters, amides, sulphonamides and carbamates. Furthermore, the development of a recyclable rhodium complex and a chiral iridium catalyst were attempted. To conclude, Chapter 5 describes the catalytic activities of three dicationic monomers. The N-alkylation of amines on water was explored. The procedure works well for a range of substituted alcohols and amines; in total, 10 compounds have been isolated in good to excellent yield (> 69%).

Introduction – Dearomatisation of Heteroaromatic Compounds The introduction provides a survey of dearomatisation reaction of heteroaromatics, with a particular focus on pyridines/pyridinium salts and furans. The mechanism, scope, and limitations of various approaches are covered, along with the goals of this project. Results and Discussion – Dearomatisation of Electron-Deficient Heteroaromatics This chapter initially explores the asymmetric addition of organometallic nucleophiles to pyridinium salts bearing a chiral counterion. Unfortunately, this approach ultimately proved unsuccessful, due to low observed enantioselectivities, and the low solubility of such salts. The second part of this chapter concerns the attempted asymmetric addition of dicarbonyl nucleophiles to electron-deficient furans, under conditions of chiral phase-transfer catalysts, affording bicyclic products in moderate enantioselectivity. Various alternative routes were also explored for the dearomatisation of furans and benzenoid systems. Introduction – Hydrogen Borrowing Alkylation Reactions with Alcohols The introduction surveys the range of methods available for the alkylation of various nucleophiles with alcohols under transition metal-catalysed conditions. Related methodologies are also explored, along with methods for the dehydrogenation of methanol. Results and Discussion - Rhodium-catalysed Methylation of Ketones Using Methanol This chapter describes the development of a novel ketone α-methylation using methanol. The development of reaction conditions is explored, followed by expansion of the substrate scope, including limitations of the methylation reaction. Mechanistic investigations support a methanol oxidation, aldol reaction/elimination, conjugate reduction pathway. Investigations into the role of O2 in the methylation reaction proved inconclusive. The utility of the reaction was also expanded via one-pot dialkylation reactions (work by Di Shen), Baeyer-Villiger oxidation of the products, and an attempted asymmetric transfer-hydrogenation. Results and Discussion - Interrupted Hydrogen Borrowing Reactions of Methanol This chapter looks to intercept intermediates from the α-methylation reaction. The selective methylenation of ketones is described, and a range of nucleophiles are screened for further functionalisation of ketones. Finally, a number of nucleophiles, including nitroalkanes, amines, peroxides and boronic acids are applied to one pot methylenation/conjugate addition protocols, affording complex products after two steps in one reaction vessel. Experimental Full experimental procedures and spectroscopic characterisation of compounds are provided.

Vinyl glycine 2 is a useful precursor to a variety of amino acids. Timothy E. Long of the University of Georgia found (Tetrahedron Lett. 2009, 50, 5067) that the o-nitrophenyl sulfoxide 1 eliminated smoothly in refluxing toluene. Alicia Boto and Rosendo Hernández of IPNA La Laguna observed (Tetrahedron Lett. 2009, 50, 3974) that a related selenoxide elimination proceeded to give the single regioisomer 4. Avelino Corma of the Universidad Politécnica de Valencia developed ( Chemical Commun. 2009, 4947) a gold catalyst for the selective hydroboration of alkynes over alkenes. Eiji Shirakawa and Tamio Hayashi of Kyoto University devised (Chemical Commun. 2009, 5088) a Ru catalyst for the conversion of an alkenyl triflate such as 8 to the corresponding bromide. Tristan H. Lambert of Columbia University found (J. Am. Chem. Soc. 2009, 131, 13930) that the dichloride 11 smoothly converted a variety of alcohols into the corresponding chlorides. Crown ethers have been used to promote SN2 reactivity by solubilizing the metal cation. Sungyul Lee of Kyunghee University, Dae Yoon Chi of Sogang University, and Choong Eui Song of Sungkyunkwan University demonstrated (Angew. Chem. Int. Ed. 2009, 48, 7683) that the inexpensive polyethylene glycols were also effective. Mugio Nishizawa of Tokushima Bunri University devised (Synlett 2009, 1175) conditions for the rapid regioselective hydration of hydroxy alkynes such as 15. Jaume Vilarrasa of the Universitat de Barcelona developed (Organic Lett. 2009, 11, 4414) a mild alternative protocol for the Nef reaction, converting a nitroalkane such as 17 into the corresponding ketone under neutral conditions. Clément Mazet of the University of Geneva optimized (Tetrahedron Lett. 2009, 50, 4141) the Ir-catalyzed conversion of an allylic alcohol 19 into the saturated aldehyde. Jonathan M. J. Williams of the University of Bath established (Angew. Chem. Int. Ed. 2009, 48, 7375) that under Ir-catalyzed “borrowing hydrogen” conditions, alkyl amines could donate alkyl groups to anilines such as 21. Danfeng Huang and Yulai Hu of Northwest Normal University devised (Organic Lett. 2009, 11, 4474) a simple protocol for conversion of an acid 23 to the Weinreb amide 24. of the Universitat