Manganese‐Catalyzed Asymmetric Hydrogenation of 3H‐Indoles DOI
Chenguang Liu, Mingyang Wang,

Yihan Xu

et al.

Angewandte Chemie International Edition, Journal Year: 2022, Volume and Issue: 61(20)

Published: March 3, 2022

The asymmetric hydrogenation (AH) of 3H-indoles represents an ideal approach to the synthesis useful chiral indoline scaffolds. However, very few catalytic systems based on precious metals have been developed realize this challenging reaction. Herein, we report a Mn-catalyzed AH with excellent yields and enantioselectivities. kinetic resolution racemic by was also achieved high s-factors construct quaternary stereocenters. Many acid-sensitive functional groups, which cannot be tolerated when using state-of-the-art ruthenium catalyst, were compatible manganese catalysis. This new process expands scope transformation highlights uniqueness earth-abundant metal reaction could proceed catalyst loadings at parts per million (ppm) level exceptional turnover number 72 350. is highest value yet reported for metal-catalyzed

Language: Английский

Catalytic methods for chemical recycling or upcycling of commercial polymers DOI
Sophia C. Kosloski-Oh, Zachary A. Wood, Yvonne Manjarrez

et al.

Materials Horizons, Journal Year: 2020, Volume and Issue: 8(4), P. 1084 - 1129

Published: Dec. 23, 2020

A review covering catalytic method development to enable efficient chemical recycling and upcycling of the most abundant commercial polymers.

Language: Английский

Citations

274
Homogeneous and heterogeneous catalysts for hydrogenation of CO2 to methanol under mild conditions DOI

Shao‐Tao Bai,

Gilles De Smet, Yuhe Liao

et al.

Chemical Society Reviews, Journal Year: 2021, Volume and Issue: 50(7), P. 4259 - 4298

Published: Jan. 1, 2021

This review summarizes the concepts, mechanisms, drawbacks and challenges of state-of-the-art catalysis for CO2 to MeOH under mild conditions. Thoughtful guidelines principles future research are presented discussed.

Language: Английский

Citations

242
Homogeneous manganese-catalyzed hydrogenation and dehydrogenation reactions DOI Creative Commons
Yujie Wang, Mingyang Wang, Yibiao Li

et al.

Chem, Journal Year: 2020, Volume and Issue: 7(5), P. 1180 - 1223

Published: Dec. 9, 2020

Language: Английский

Citations

217
Lutidine‐Based Chiral Pincer Manganese Catalysts for Enantioselective Hydrogenation of Ketones DOI
Linli Zhang,

Yitian Tang,

Zhaobin Han

et al.

Angewandte Chemie International Edition, Journal Year: 2019, Volume and Issue: 58(15), P. 4973 - 4977

Published: Feb. 18, 2019

A series of MnI complexes containing lutidine-based chiral pincer ligands with modular and tunable structures has been developed. The complex shows unprecedentedly high activities (up to 9800 TON; TON=turnover number), broad substrate scope (81 examples), good functional-group tolerance, excellent enantioselectivities (85-98 % ee) in the hydrogenation various ketones. These aspects are rare earth-abundant metal catalyzed hydrogenations. utility protocol have demonstrated asymmetric synthesis a variety key intermediates for drugs. Preliminary mechanistic investigations indicate that an outer-sphere mode substrate-catalyst interactions probably dominates catalysis.

Language: Английский

Citations

191
Hydrogenative Depolymerization of Nylons DOI Creative Commons
Amit Kumar, Niklas von Wolff,

Michael Rauch

et al.

Journal of the American Chemical Society, Journal Year: 2020, Volume and Issue: 142(33), P. 14267 - 14275

Published: July 24, 2020

The widespread crisis of plastic pollution demands discovery new and sustainable approaches to degrade robust plastics such as nylons. Using a green approach based on hydrogenation, in the presence ruthenium pincer catalyst at 150 °C 70 bar H2, we report here first example hydrogenative depolymerization conventional, widely used nylons polyamides, general. Under same catalytic conditions, also demonstrate hydrogenation polyurethane produce diol, diamine, methanol. Additionally, an where monomers (and oligomers) obtained from process can be dehydrogenated back poly(oligo)amide approximately similar molecular weight, thus completing closed loop cycle for recycling polyamides. Based experimental density functional theory studies, propose that is facilitated by metal–ligand cooperativity. Overall, this unprecedented transformation, albeit proof concept level, offers toward cleaner route

Language: Английский

Citations

161
Manganese-catalyzed hydrogenation, dehydrogenation, and hydroelementation reactions DOI
Kuhali Das, Satyadeep Waiba, Akash Jana

et al.

Chemical Society Reviews, Journal Year: 2022, Volume and Issue: 51(11), P. 4386 - 4464

Published: Jan. 1, 2022

The emerging field of organometallic catalysis has shifted towards research on Earth-abundant transition metals due to their ready availability, economic advantage, and novel properties. In this case, manganese, the third most abundant transition-metal in Earth's crust, emerged as one leading competitors. Accordingly, a large number molecularly-defined Mn-complexes been synthesized employed for hydrogenation, dehydrogenation, hydroelementation reactions. regard, catalyst design is based three pillars, namely, metal-ligand bifunctionality, ligand hemilability, redox activity. Indeed, developed catalysts not only differ chelating atoms they possess but also working principles, thereby different turnover numbers product molecules. Hence, critical assessment molecularly defined manganese terms atoms, reaction conditions, mechanistic pathway, significant. Herein, we analyze complexes catalytic activity, versatility allow multiple transformations routes convert substrates target This article will be helpful get significant insight into design, aiding design.

Language: Английский

Citations

158
Development of a practical non-noble metal catalyst for hydrogenation of N-heteroarenes DOI
Veronica Papa, Yi-Xuan Cao,

Anke Spannenberg

et al.

Nature Catalysis, Journal Year: 2020, Volume and Issue: 3(2), P. 135 - 142

Published: Jan. 6, 2020

Language: Английский

Citations

155
Robust and efficient hydrogenation of carbonyl compounds catalysed by mixed donor Mn(I) pincer complexes DOI Creative Commons
Wenjun Yang, Ivan Yu. Chernyshov, Robin K. A. van Schendel

et al.

Nature Communications, Journal Year: 2021, Volume and Issue: 12(1)

Published: Jan. 4, 2021

Abstract Any catalyst should be efficient and stable to implemented in practice. This requirement is particularly valid for manganese hydrogenation catalysts. While representing a more sustainable alternative conventional noble metal-based systems, catalysts are prone degrade under catalytic conditions once operation temperatures high. Herein, we report highly Mn(I)-CNP pre-catalyst which gives rise the excellent productivity (TOF° up 41 000 h −1 ) stability (TON 200 000) catalysis. system enables near-quantitative of ketones, imines, aldehydes formate esters at loadings as low 5–200 p.p.m. Our analysis points crucial role activation step performance system. employing alkoxide bases can ultimately provide catalytically competent species hydrogen atmosphere, Mn(I) with hydride donor promoters, e.g. KHBEt 3 , dramatically improves eliminates induction times associated slow activation.

Language: Английский

Citations

151
Metal-catalyzed plastic depolymerization DOI Creative Commons
Kishor V. Khopade, Samir H. Chikkali, Nagaraju Barsu

et al.

Cell Reports Physical Science, Journal Year: 2023, Volume and Issue: 4(5), P. 101341 - 101341

Published: March 29, 2023

Polymers have become an indispensable part of our daily lives, and today we produce around 370 MT plastic per year. Only about 20% it is being recycled, the rest, 80%, unleashed into environment without appropriate treatment. This calls forth evaluation strategies available for mitigating menace "after-use" waste. Various approaches evolved over a decade are at different levels development. Plastic depolymerization upcycling considered some most prominent long-term solutions. The metal-catalyzed waste to chemical feedstocks has emerged as one promising ways address global pollution. Therefore, this review aims examine methods, notify recent progress, pinpoint current gaps, gauge potential strategy. Both homogeneous heterogeneous catalysts been reported depolymerize various polymers last decade. Considerable advances in metal-mediated polyolefins, polyesters, polycarbonates, polyurethanes, polyamides, polyethers. above produces monomers or intermediates, which can be used again polymerization thus brings back circularity. overview debates usage high temperatures, sophisticated ligands, expensive metals, stoichiometric reagents, etc., depolymerization. Thus, summarizes understanding fundamental science depolymerization, remaining scientific challenges, opportunities.

Language: Английский

Citations

43
Mechanistic Studies of Hydride Transfer to Imines from a Highly Active and Chemoselective Manganate Catalyst DOI

Frederik Freitag,

Τ. Irrgang, Rhett Kempe

et al.

Journal of the American Chemical Society, Journal Year: 2019, Volume and Issue: 141(29), P. 11677 - 11685

Published: June 28, 2019

We introduce a highly active and chemoselective manganese catalyst for the hydrogenation of imines. The has large scope, can reduce aldimines ketimines, tolerates variety functional groups, among them sensitive examples such as an olefin, ketone, nitriles, nitro aryl iodo substituent or benzyl ether. could investigate transfer step between imines hydride complex in detail. found that double deprotonation ligand is essential excess base does not lead to higher rate step. identified actual K–Mn-bimetallic species obtain structure K–Mn formed after by X-ray analysis. NMR experiments indicate well-defined reaction, which first order imine, bimetallic (K–Mn) hydride, independent from concentration potassium base. propose outer-sphere mechanism protons do seem be involved rate-determining step, leading transiently negatively charged nitrogen atom substrate reacts rapidly with HOtBu (2-methylpropan-2-ol) produce amine. This based on several observations, no dependency reaction concentration, observable amide complex, high constant conducted Hammett study. Furthermore, hydrogen catalytic cycle was experimentally probed monitored subsequent quantitative regeneration H2.

Language: Английский

Citations

132