Recent Developments in Enantioselective Transition Metal Catalysis Featuring Attractive Noncovalent Interactions between Ligand and Substrate

ACS Catalysis, Год журнала: 2020, Номер 10(18), С. 10672 - 10714

Опубликована: Авг. 14, 2020

Enantioselective transition metal catalysis is an area very much at the forefront of contemporary synthetic research. The development processes that enable efficient synthesis enantiopure compounds unquestionable importance to chemists working within many diverse fields central science. Traditional approaches solving this challenge have typically relied on leveraging repulsive steric interactions between chiral ligands and substrates in order raise energy one diastereomeric states over other. By contrast, Review examines alternative tactic which a set attractive noncovalent operating are used control enantioselectivity. Examples where creative approach has been successfully applied render fundamental enantioselective presented discussed. In cases examined, ligand scaffold carefully designed accommodate these interactions, while others, critical was only elucidated subsequent computational mechanistic studies. Through exploration discussion recent reports encompassing wide range reaction classes, we hope inspire continue develop asymmetric transformations based powerful concept.

Язык: Английский

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Metal Stereogenicity in Asymmetric Transition Metal Catalysis

Chemical Reviews, Год журнала: 2023, Номер 123(8), С. 4764 - 4794

Опубликована: Март 29, 2023

Chiral transition metal catalysts represent a powerful and economic tool for implementing stereocenters in organic synthesis, with the center providing strong chemical activation upon its interaction substrates or reagents, while overall chirality of complex achieves desired stereoselectivity. Often, chiral topology implements stereogenic center, which is then involved origin asymmetric induction. This review provides comprehensive survey reported formally constitutes stereocenter. A goes along an complex, regardless whether ligands are achiral. Implications catalyst design mechanism induction discussed half-sandwich, tetracoordinated, pentacoordinated, hexacoordinated complexes containing center. The distinguishes between originating from coordination to those solely composed optically inactive (achiral rapidly interconverting enantiomers) prior complexation (dubbed “chiral-at-metal” catalysts).

Язык: Английский

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Chiral-at-metal catalysts: history, terminology, design, synthesis, and applications

Chemical Society Reviews, Год журнала: 2025, Номер unknown

Опубликована: Янв. 1, 2025

Chiral-at-metal catalysts, containing only achiral ligands, utilize the metal as sole stereogenic center and catalytic center. They represent an emerging powerful class of chiral transition catalysts for asymmetric catalysis.

Язык: Английский

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A diversity of recently reported methodology for asymmetric imine reduction

Organic Chemistry Frontiers, Год журнала: 2020, Номер 7(20), С. 3312 - 3342

Опубликована: Янв. 1, 2020

This review describes recent developments in enantioselective imine reduction, including related substrates which a CN bond is the target for and in situ methods.

Язык: Английский

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Cycloiridated Helicenes as Chiral Catalysts in the Asymmetric Transfer Hydrogenation of Imines

ACS Catalysis, Год журнала: 2022, Номер 12(17), С. 10793 - 10800

Опубликована: Авг. 19, 2022

The asymmetric synthesis of optically pure and conformationally locked oxabenzo[5]helicenes bearing pyridin-2-yl or isoquinolin-3-yl substituents their transformation into the corresponding cycloiridated organometallics are described. These helically chiral Cp*IrIII(X)C,N-complexes (X = Cl, I) also contain a configurationally unstable pseudotetrahedral iridium center. This center undergoes epimerization at room temperature, its relative stereochemistry, especially in solid state, depends on nature coordinated ligands. Cycloiridated helicenes were used transfer hydrogenation prochiral aromatic imines with formic acid/triethylamine to reach up 96:4 er. It is assumed that chirality controlled by auxiliary helix rather than IrIII stereogenic iridacycles.

Язык: Английский

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Unmasking the reverse reactivity of cyclic N-sulfonyl ketimines: multifaceted applications in organic synthesis

Chemical Communications, Год журнала: 2021, Номер 57(72), С. 9010 - 9028

Опубликована: Янв. 1, 2021

This feature article covers the recent status on reactivities of α-alkyl cyclic N -sulfonyl ketimines as resourceful nucleophiles, targeting fused carbo- and heterocycles, aza-arenes etc . In addition, mechanistic studies have been presented.

Язык: Английский

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Enhanced Catalytic Activity of Iridium(III) Complexes by Facile Modification of C,N-Bidentate Chelating Pyridylideneamide Ligands

Inorganic Chemistry, Год журнала: 2017, Номер 56(19), С. 11688 - 11701

Опубликована: Сен. 12, 2017

A set of aryl-substituted pyridylideneamide (PYA) ligands with variable donor properties owing to a pronounced zwitterionic and neutral diene-type resonance structure were used as electronically flexible at pentamethylcyclopentadienyl (Cp*) iridium center. The straightforward synthesis this type ligand allows for an easy incorporation substituents such methoxy groups in different positions the phenyl ring C,N-bidentate chelating PYA. These modifications considerably enhance catalytic activity coordinated center toward aerobic transfer hydrogenation carbonyls imines well hydrosilylation phenylacetylene. Moreover, these PYA complexes catalyze base-free aldehydes, lesser extent also ketones. Under standard conditions including base, aldehydes are rapidly oxidized carboxylic acids rather than reduced corresponding alcohol, is observed under conditions.

Язык: Английский

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Ruthenacycles and Iridacycles as Transfer Hydrogenation Catalysts

Molecules, Год журнала: 2021, Номер 26(13), С. 4076 - 4076

Опубликована: Июль 3, 2021

In this review, we describe the synthesis and use in hydrogen transfer reactions of ruthenacycles iridacycles. The review limits itself to metallacycles where a ligand is bound bidentate fashion either ruthenium or iridium via carbon-metal sigma bond, as well dative bond from heteroatom an N-heterocyclic carbene. Pincer complexes fall outside scope. Described are applications (asymmetric) hydrogenation aldehydes, ketones, imines, reductive aminations. Oxidation reactions, i.e., classical Oppenauer oxidation, which reverse hydrogenation, dehydrogenations oxidations with oxygen, described. Racemizations alcohols secondary amines also catalyzed by

Язык: Английский

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Lewis Acid‐Catalyzed Reductive Amination of Aldehydes and Ketones with N,N‐Dimethylformamide as Dimethylamino Source, Reductant and Solvent

Advanced Synthesis & Catalysis, Год журнала: 2017, Номер 360(3), С. 485 - 490

Опубликована: Ноя. 14, 2017

Abstract A practical zinc acetate dihydrate‐catalyzed reductive amination of various carbonyl compounds with N , ‐dimethylformamide (DMF) as dimethylamino (Me 2 N) source, reductant and solvent has been developed. This reaction shows broad substrate scope, good functional group tolerance, avoids the need for a pressure‐proof reactor column chromatographic isolation operations gives up to 98% yield, make it an attractive method preparation tertiary ‐dimethylamines. magnified image

Язык: Английский

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Nickel-Catalyzed Asymmetric Transfer Hydrogenation and α-Selective Deuteration ofN-Sulfonyl Imines with Alcohols: Access to α-Deuterated Chiral Amines

Organic Letters, Год журнала: 2020, Номер 22(21), С. 8278 - 8284

Опубликована: Окт. 12, 2020

A nickel-catalyzed enantioselective transfer hydrogenation and deuteration of N-sulfonyl imines was developed. Excellent α-selectivity high deuterium content were achieved by using inexpensive 2-propanol-d8 as a source. As highlight, no β-C-H the remote C-H amines occurred, which is hard to achieve other or hydrogen isotope exchange with D2O. Mechanism studies indicated stepwise pathway through [Ni-D] intermediate.

Язык: Английский

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