scholarly journals Chemoselective Transfer Hydrogenation of α,β-Unsaturated Ketones Catalyzed by Iridium Complexes

SynOpen ◽  
2021 ◽  
Vol 05 (01) ◽  
pp. 36-42
Author(s):  
Renshi Luo ◽  
Yanping Xia ◽  
Lu Ouyang ◽  
Jianhua Liao ◽  
Xiao Yang
Keyword(s):  
Formic Acid ◽  
Functional Groups ◽  
Organic Solvents ◽  
Mixed Solvents ◽  
Transfer Hydrogenation ◽  
Scale Transformation ◽  
Iridium Complexes ◽  
Practical Application ◽  
Unsaturated Ketones ◽  
Electron Withdrawing Substituents

AbstractEfficient chemoselective transfer hydrogenation of the C=C bond of α,β-unsaturated ketones has been developed, using the iridium complexes containing pyridine-imidazolidinyl ligands as catalysts and formic acid as a hydrogen source. In comparison with organic solvents or H2O as solvent, the mixed solvents of H2O and MeOH are critical for a high catalytic chemoselective transformation. This chemoselective transfer hydrogenation can be carried out in air, which is operationally simple, allowing a wide variety of α,β-unsaturated substrates with different functional groups (electron-donating and electron-withdrawing substituents) leading to chemoselective transfer hydrogenation in excellent yields. The practical application of this protocol is demonstrated by a gram-scale transformation.

Construction of α-alkylated amines by Iridium Complexes-Catalyzed One-Step Transfer Hydrogenation of C=C and C=N Bond

Synthesis ◽  
2020 ◽  
Author(s):  
Yanping Xia ◽  
Lu Ouyang ◽  
Jianhua Liao ◽  
Xiao Yang ◽  
Renshi Luo
Keyword(s):  
Reductive Amination ◽  
Transfer Hydrogenation ◽  
Scale Transformation ◽  
Iridium Complexes ◽  
Practical Application ◽  
One Pot ◽  
System A ◽  
Wide Range ◽  
One Step ◽  
Amine Compounds

Hydrogenation of C=C bond and reductive amination is important transformation utilized in chemistry. An efficient and facile one-pot transfer hydrogenation of C=C bond and reductive amination of C=N bond of enones and amines was reported using the iridium complexes as catalysts and formic acid as hydrogen source in aqueous medium, which shows environmentally friendly. In this catalytic system, a wide range of α-alkylated amine compounds were obtained in excellent yields by one-pot transfer hydrogenation of C=C bond and reductive amination. The practical application of this protocol is characterized by gram-scale transformation.

Hydrogen transfer from formic acid to alkynes catalyzed by a diruthenium complex

2001 ◽  
Vol 79 (5-6) ◽  
pp. 915-921 ◽  
Author(s):  
Yuan Gao ◽  
Michael C Jennings ◽  
Richard J Puddephatt
Keyword(s):  
Carbon Dioxide ◽  
Formic Acid ◽  
Hydrogen Transfer ◽  
Hydrogen Donor ◽  
Transfer Hydrogenation ◽  
Stable Complex ◽  
Terminal Alkynes ◽  
Hydrogenation Catalysis ◽  
Diruthenium Complex ◽  
Electron Withdrawing Substituents

The diruthenium(0) complex [Ru2(µ-CO)(CO)4(µ-dppm)2] (1) (dppm = Ph2PCH2PPh2), is a catalyst for the transfer hydrogenation, using formic acid as hydrogen donor, of the alkynes PhCºCPh, PhCºCMe, EtCºCEt, and PrCºCPr but not of the terminal alkynes HCºCH, PhCºCH, BuCºCH, or the alkynes containing one or two electron-withdrawing substituents PhCºCCO2Me and MeO2CCtriple bondCCO2Me. In the successful reactions, the formic acid is first decomposed to carbon dioxide and hydrogen, which then hydrogenates the alkynes in a slower reaction. In the unsuccessful reactions, the decomposition of formic acid is strongly retarded by the alkyne. In the case with the alkyne PhCºCH, it is shown that the alkyne reacts with protonated 1 to give first [Ru2(µ-CPh=CH2)(CO)4(µ-dppm)2][HCO2], which then isomerizes to give the catalytically inactive, stable complex [Ru2(µ-CH=CHPh)(CO)4(µ-dppm)2][HCO2]. This complex has been structurally characterized and both of the µ-styrenyl complexes are shown to be fluxional in solution.Key words: ruthenium, hydrogenation, catalysis, binuclear..

Iridium-catalyzed Transfer Hydrogenation for Construction of Quinolines from 2-Aminobenzyl Alcohols with Enones in Water

Synthesis ◽  
2021 ◽  
Author(s):  
Nian hua Luo ◽  
HongLing Shui ◽  
Yuhong Zhong ◽  
Jiu-Zhong Huang ◽  
Renshi Luo
Keyword(s):  
Functional Groups ◽  
Catalytic System ◽  
Control Experiment ◽  
High Efficiency ◽  
Transfer Hydrogenation ◽  
Environmentally Benign ◽  
Iridium Complex ◽  
Unsaturated Ketones ◽  
Scale Control

Herein, we describe a method for the synthesis of functionalized quinolines from 2-aminobenzyl alcohols with α, β-unsaturated ketones. This method exhibits various functional groups tolerance, high-efficiency, environmentally benign and can be performed on a gram scale. Control experiment suggests this transformation is accomplished by iridium complex-catalyzed transfer hydrogenation, which is then followed by the Friedländer cyclization. The results display the alkali is essential for the high selectivities of this catalytic system.

Participation by some oxygen containing groups in hypobromous acid addition to double bond

1983 ◽  
Vol 48 (12) ◽  
pp. 3660-3673 ◽  
Author(s):  
Pavel Kočovský
Keyword(s):  
Double Bond ◽  
Functional Groups ◽  
Relative Reactivity ◽  
Product Analysis ◽  
Acid Addition ◽  
Hypobromous Acid ◽  
Electron Withdrawing Substituents

5(O)n and 6(O)π,n participations by some oxygen containing functional groups in the course of reaction with hypobromous acid have been studied on olefinic models of steroid type (I and II). The ability of these groups to participate has been compared on the basis of their relative reactivity with water (as externally attacking nucleophile) competing with participation. The results of the product analysis show that the ability to react with 5(O)n participation decreases in the order HO > CH3O ≃ CH3OCH2O > CH3CO2 > HCO2 > CH3SO3 ≥ (C2H5O)2PO2 > C6H5CO2 > O2NO ≫ CF3CO2, C2H5OCO2; in the last two functional groups is this ability completely suppressed. The 6(O)π,n participation comes in consideration only for compounds of the type II bearing the groups with the -X=O moiety which are ordered in the following sequence: C2H5OCO2 ≃ CH3CO2 ≥ (C2H5O)2PO2 > HCO2 > C6H5CO2. The remaining functional groups (CF3CO2, O2NO and CH3SO3do not undergo this process. Generally, it is valid that introduction of electron-withdrawing substituents into a participating group impedes or completely suppresses its ability to participate.

scholarly journals The Role of Peptides in the Design of Electrochemical Biosensors for Clinical Diagnostics

Biosensors ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 246
Author(s):  
Patrick Severin Sfragano ◽  
Giulia Moro ◽  
Federico Polo ◽  
Ilaria Palchetti
Keyword(s):  
Functional Groups ◽  
Synthetic Peptides ◽  
Clinical Diagnostics ◽  
Electrochemical Biosensors ◽  
Practical Application ◽  
Design And Development ◽  
Electrode Surfaces ◽  
Electrochemical Transducers ◽  
Target Analyte

Peptides represent a promising class of biorecognition elements that can be coupled to electrochemical transducers. The benefits lie mainly in their stability and selectivity toward a target analyte. Furthermore, they can be synthesized rather easily and modified with specific functional groups, thus making them suitable for the development of novel architectures for biosensing platforms, as well as alternative labelling tools. Peptides have also been proposed as antibiofouling agents. Indeed, biofouling caused by the accumulation of biomolecules on electrode surfaces is one of the major issues and challenges to be addressed in the practical application of electrochemical biosensors. In this review, we summarise trends from the last three years in the design and development of electrochemical biosensors using synthetic peptides. The different roles of peptides in the design of electrochemical biosensors are described. The main procedures of selection and synthesis are discussed. Selected applications in clinical diagnostics are also described.

A Hantzsch Amido Dihydropyridine as a Transfer Hydrogenation Reagent for α,β-Unsaturated Ketones

2016 ◽  
Vol 81 (9) ◽  
pp. 3528-3532 ◽  
Author(s):  
Scott A. Van Arman ◽  
Austin J. Zimmet ◽  
Ian E. Murray
Keyword(s):  
Transfer Hydrogenation ◽  
Unsaturated Ketones

scholarly journals Bis-NHC–Ag/Pd(OAc)2 Catalytic System Catalyzed Transfer Hydrogenation Reaction

Catalysts ◽  
2020 ◽  
Vol 11 (1) ◽  
pp. 8
Author(s):  
Hui-Ju Chen ◽  
Chien-Cheng Chiu ◽  
Tsui Wang ◽  
Dong-Sheng Lee ◽  
Ta-Jung Lu
Keyword(s):  
Functional Groups ◽  
Catalytic System ◽  
High Efficiency ◽  
Aqueous Media ◽  
Hydrogenation Reaction ◽  
Transfer Hydrogenation ◽  
Terminal Alkynes ◽  
Wide Range ◽  
Transfer Hydrogenation Reaction

The bis-NHC–Ag/Pd(OAc)2 catalytic system (NHC = N-heterocyclic carbene), a combination of bis-NHC–Ag complex and Pd(OAc)2, was found to be a smart catalyst in the Pd-catalyzed transfer hydrogenation of various functionalized arenes and internal/terminal alkynes. The catalytic system demonstrated high efficiency for the reduction of a wide range of various functional groups such as carbonyls, alkynes, olefins, and nitro groups in good to excellent yields and high chemoselectivity for the reduction of functional groups. In addition, the protocol was successfully exploited to stereoselectivity for the transformation of alkynes to alkenes in aqueous media under air. This methodology successfully provided an alternative useful protocol for reducing various functional groups and a simple operational protocol for transfer hydrogenation.

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