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

Manganese‐Catalyzed Asymmetric Hydrogenation of Quinolines Enabled by π–π Interaction** DOI
Chenguang Liu, Mingyang Wang, Shihan Liu

et al.

Angewandte Chemie International Edition, Journal Year: 2020, Volume and Issue: 60(10), P. 5108 - 5113

Published: Nov. 26, 2020

Abstract The non‐noble metal‐catalyzed asymmetric hydrogenation of N‐heteroaromatics, quinolines, is reported. A new chiral pincer manganese catalyst showed outstanding catalytic activity in the affording high yields and enantioselectivities (up to 97 % ee). turnover number 3840 was reached at a low loading (S/C=4000), which competitive with most effective noble metal catalysts for this reaction. precise regulation enantioselectivity were ensured by π–π interaction.

Language: Английский

Citations

132
Unmasking the Ligand Effect in Manganese-Catalyzed Hydrogenation: Mechanistic Insight and Catalytic Application DOI
Yujie Wang, Lei Zhu, Zhihui Shao

et al.

Journal of the American Chemical Society, Journal Year: 2019, Volume and Issue: 141(43), P. 17337 - 17349

Published: Oct. 21, 2019

Manganese-catalyzed hydrogenation reactions have attracted broad interest since the first report in 2016. Among reported catalytic systems, Mn catalysts supported by tridentate PNP- and NNP-pincer ligands most commonly been used. For example, a number of PNP-Mn pincer for aldehydes, aldimines, ketones, nitriles, esters. Furthermore, various NNP-Mn shown to be active less-reactive substrates such as amides, carbonates, carbamates, urea derivations. These observations indicated that exhibit higher reactivity than their PNP counterparts. Such ligand effect Mn-catalyzed has yet confirmed. Herein, we investigated origin applicability this effect. A combination experimental theoretical investigations showed on complexes were more electron-rich less sterically hindered counterparts, leading series reactions. Inspired hydrogenations, developed N-heterocycles. Specifically, hydrogenated N-heterocycles (32 examples) with up 99% yields, corresponding afforded low under same conditions. This verified is generally applicable both carbonyl noncarbonyl based catalysis.

Language: Английский

Citations

129
Catalytic Hydrogenation of Cyclic Carbonates using Manganese Complexes DOI Creative Commons
Akash Kaithal, Markus Hölscher, Walter Leitner

et al.

Angewandte Chemie International Edition, Journal Year: 2018, Volume and Issue: 57(41), P. 13449 - 13453

Published: Aug. 22, 2018

Catalytic hydrogenation of cyclic carbonates to diols and methanol was achieved using a molecular catalyst based on earth-abundant manganese. The complex [Mn(CO)

Language: Английский

Citations

124
Manganese-catalyzed hydroboration of carbon dioxide and other challenging carbonyl groups DOI Creative Commons
Christina Erken, Akash Kaithal, Suman Sen

et al.

Nature Communications, Journal Year: 2018, Volume and Issue: 9(1)

Published: Oct. 24, 2018

Reductive functionalization of the C=O unit in carboxylic acids, carbonic acid derivatives, and ultimately carbon dioxide itself is a challenging task key importance for synthesis value-added chemicals. In particular, it can open novel pathways valorization non-fossil feedstocks. Catalysts based on earth-abundant, cheap, benign metals would greatly contribute to development sustainable synthetic processes derived from this concept. Herein, manganese pincer complex [Mn(Ph2PCH2SiMe2)2NH(CO)2Br] (1) reported enable reduction broad range carbonates, even CO2 using pinacolborane as reducing agent. The shown operate under mild reaction conditions (80-120 °C), low catalyst loadings (0.1-0.2 mol%) runs solvent-less conditions. Mechanistic studies including crystallographic characterisation borane adduct imply that metal-ligand cooperation facilitates substrate activation.

Language: Английский

Citations

122
Manganese Catalyzed Hydrogenation of Carbamates and Urea Derivatives DOI
Uttam Kumar Das, Amit Kumar,

Yehoshoa Ben‐David

et al.

Journal of the American Chemical Society, Journal Year: 2019, Volume and Issue: 141(33), P. 12962 - 12966

Published: July 31, 2019

We report the hydrogenation of carbamates and urea derivatives, two most challenging carbonyl compounds to be hydrogenated, catalyzed for first time by a complex an earth-abundant metal. The reaction these CO2-derived compounds, manganese pincer complex, yields methanol in addition amine alcohol, which makes this methodology sustainable alternative route conversion CO2 methanol, involving base-metal catalyst. Moreover, proceeds under mild pressure (20 bar). Our observations support mechanism Mn–H complex. A plausible catalytic cycle is proposed based on informative mechanistic experiments.

Language: Английский

Citations

111
Manganese(I)‐Catalyzed β‐Methylation of Alcohols Using Methanol as C1 Source DOI Creative Commons
Akash Kaithal, Pit van Bonn, Markus Hölscher

et al.

Angewandte Chemie International Edition, Journal Year: 2019, Volume and Issue: 59(1), P. 215 - 220

Published: Oct. 25, 2019

Highly selective β-methylation of alcohols was achieved using an earth-abundant first row transition metal in the air stable molecular manganese complex [Mn(CO)

Language: Английский

Citations

111
Efficient catalytic conversion of terminal/internal epoxides to cyclic carbonates by porous Co(ii) MOF under ambient conditions: structure–property correlation and computational studies DOI
Bhavesh Parmar, Parth Patel, Renjith S. Pillai

et al.

Journal of Materials Chemistry A, Journal Year: 2019, Volume and Issue: 7(6), P. 2884 - 2894

Published: Jan. 1, 2019

Efficient CO2 capture/utilization by Co(ii) MOF as a heterogeneous catalyst in CO2–epoxide cycloaddition at ambient condition has been investigated and correlated with computational studies.

Language: Английский

Citations

108
Recent Progress with Pincer Transition Metal Catalysts for Sustainability DOI Open Access
Luca Piccirilli, Danielle L. J. Pinheiro, Martin Nielsen

et al.

Catalysts, Journal Year: 2020, Volume and Issue: 10(7), P. 773 - 773

Published: July 11, 2020

Our planet urgently needs sustainable solutions to alleviate the anthropogenic global warming and climate change. Homogeneous catalysis has potential play a fundamental role in this process, providing novel, efficient, at same time eco-friendly routes for both chemicals energy production. In particular, pincer-type ligation shows promising properties terms of long-term stability selectivity, as well allowing mild reaction conditions low catalyst loading. Indeed, pincer complexes have been applied plethora chemical processes, such hydrogen release, CO2 capture conversion, N2 fixation, biomass valorization synthesis high-value fuels. work, we show main advances last five years use transition metal key catalytic processes aiming more

Language: Английский

Citations

97
Metal-catalyzed hydrogenation and dehydrogenation reactions for efficient hydrogen storage DOI
Takuya Shimbayashi, Ken‐ichi Fujita

Tetrahedron, Journal Year: 2020, Volume and Issue: 76(11), P. 130946 - 130946

Published: Jan. 18, 2020

Language: Английский

Citations

82
Catalytic Hydrogenation of Polyurethanes to Base Chemicals: From Model Systems to Commercial and End-of-Life Polyurethane Materials DOI Creative Commons
Laurynas Gausas, Steffan K. Kristensen, Hongwei Sun

et al.

JACS Au, Journal Year: 2021, Volume and Issue: 1(4), P. 517 - 524

Published: April 6, 2021

Polyurethane (PU) is a highly valued polymer prepared from diisocyanates and polyols, it used in everyday products, such as shoe soles, mattresses, insulation materials, but also for the construction of sophisticated parts medical devices, wind turbine blades, aircrafts, spacecrafts, to name few. As PU most commonly thermoset composed cross-linked structures, its recycling complicated inefficient, leading increasing waste accumulating every year. Catalytic hydrogenation represents an atom-efficient means deconstruction polyurethanes, so far identification efficient catalyst disassembly real-life end-of-life samples has not been demonstrated. In this work, we reveal that commercially available catalyst, Ir-iPrMACHO, under 30 bar H2 150–180 °C, general effective four cornerstones PU: flexible solid, foamed, rigid isolation aromatic amines polyol fraction. For first time, variety commercial including examples foams, inline skating wheels, deconstructed into two fractions. Most desirable, our reaction conditions include use isopropyl alcohol representative green solvent. It speculated partial glycolysis at surface particles taking place solvent temperatures presence catalytic amounts base. more solubilized fragments becomes possible. isolated anilines are precursors original isocyanate building blocks, methods their conversion well-known, work reported paper provides realistic indication potential circular plastic economy solution PU. Preliminary experiments were undertaken applying Mn-iPrMACHO foam. Although successful, forcing required than those when Ir-iPrMACHO.

Language: Английский

Citations

76