N-Heterocyclic Carbene Adducts of Main Group Elements and Their Use as Ligands in Transition Metal Chemistry

Chemical Reviews, Journal Year: 2019, Volume and Issue: 119(12), P. 6994 - 7112

Published: April 15, 2019

N-Heterocyclic carbenes (NHC) are nowadays ubiquitous and indispensable in many research fields, it is not possible to imagine modern transition metal main group element chemistry without the plethora of available NHCs with tailor-made electronic steric properties. While their suitability act as strong ligands toward metals has led numerous applications NHC complexes homogeneous catalysis, σ-donating adaptable π-accepting abilities have also contributed an impressive vitalization isolation characterization adducts almost any element. Formally, coordination Lewis acids affords a transfer nucleophilicity from carbene carbon atom attached exocyclic moiety, low-valent low-coordinate p-block elements lone pairs and/or polarized carbon-element π-bonds able themselves basic donor metals. Accordingly, availability large number novel only produced new varieties already existing ligand classes but allowed establishment unusual often unprecedented element–metal bonds. This review aims at summarizing this development comprehensively covers usage N-heterocyclic chemistry.

Language: Английский

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Asymmetric synthesis of allylic compoundsviahydrofunctionalisation and difunctionalisation of dienes, allenes, and alkynes

Chemical Society Reviews, Journal Year: 2020, Volume and Issue: 49(7), P. 2060 - 2118

Published: Jan. 1, 2020

This review article provides an overview of progress in asymmetric synthesis allylic compoundsviahydrofunctionalisation and difunctionalisation dienes, allenes, alkynes.

Language: Английский

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Stereodivergent Coupling of 1,3-Dienes with Aldimine Esters Enabled by Synergistic Pd and Cu Catalysis

Journal of the American Chemical Society, Journal Year: 2019, Volume and Issue: 141(37), P. 14554 - 14559

Published: Sept. 3, 2019

Herein we describe the use of synergistic Pd and Cu catalysis for stereodivergent coupling reactions between 1,3-dienes aldimine esters. By using different enantiomers two metal catalysts, all four stereoisomers products, which have vicinal stereocenters, could be accessed with high diastereo- enantioselectivity. This atom-economical cross-coupling reaction has a wide substrate scope good functional group tolerance. Our work highlights power asymmetric involving Pd-hydride catalysts.

Language: Английский

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Pushing Electrons—Which Carbene Ligand for Which Application?

Organometallics, Journal Year: 2018, Volume and Issue: 37(3), P. 275 - 289

Published: Feb. 12, 2018

This tutorial explores the diversity and characteristics of C-donor ligands. Particular emphasis is put on conceptual design electronic properties for applications in coordination chemistry. More specifically, implications both σ π effects are discussed. Cyclic (alkyl)(amino)carbenes as well methanediides carbones brought perspective to "conventional" N-heterocylic carbenes, mesoionic Fischer Schrock carbene

Language: Английский

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Catalytic Enantio- and Regioselective Addition of Nucleophiles in the Intermolecular Hydrofunctionalization of 1,3-Dienes

ACS Catalysis, Journal Year: 2019, Volume and Issue: 10(2), P. 1060 - 1076

Published: Dec. 12, 2019

Catalytic enantioselective synthesis of small-molecule building blocks with allylic stereogenic centers is an important objective in organic synthesis, but preparing this motif wherein the adjacent olefin 1,2-disubstituted a single step tremendous challenge. Late-transition-metal-catalyzed intermolecular couplings nucleophiles and 1,3-dienes hydrofunctionalization reactions have quickly emerged as compelling approach to these related compounds. In Perspective, we illustrate how diene hydrofunctionalizations provided avenue complex, highly desirable chemical space that not readily accessed by other technologies. We also aim provide some insight into varying mechanistic pathways nuances myriad help inform future reaction catalyst design.

Language: Английский

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Synergistic Pd/Amine-Catalyzed Stereodivergent Hydroalkylation of 1,3-Dienes with Aldehydes: Reaction Development, Mechanism, and Stereochemical Origins

Journal of the American Chemical Society, Journal Year: 2021, Volume and Issue: 143(29), P. 10948 - 10962

Published: July 15, 2021

Metal-hydride-catalyzed hydroalkylation of 1,3-dienes with enolizable carbonyl compounds is an atom- and step-economical method for preparing chiral molecules allylic stereocenters. Although high diastereo- enantioselectivities have been achieved many coupling partners, aldehydes not yet used this purpose because they are less stable than other under basic conditions the potential to rapidly epimerize at α-position. Moreover, stereodivergent reactions access complementary diastereomers vicinal stereocenters challenging. Herein, we describe a synergistic palladium/amine catalyst system that allowed us achieve first aldehydes. By choosing appropriate combination palladium amine catalysts, could obtain either syn or anti products, therefore provides highly enantioselective α,β-vicinal Density functional theory calculations revealed mechanism involving PdH formation migratory insertion into alkene, followed by C–C bond formation. The origin stereoselectivities was investigated means distortion/interaction analysis.

Language: Английский

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Synergizing palladium with Lewis base catalysis for stereodivergent coupling of 1,3-dienes with pentafluorophenyl acetates

Chem, Journal Year: 2022, Volume and Issue: 8(10), P. 2784 - 2796

Published: Aug. 17, 2022

Language: Английский

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Catalytic Asymmetric Hydroalkoxylation and Formal Hydration and Hydroaminoxylation of Conjugated Dienes

Journal of the American Chemical Society, Journal Year: 2023, Volume and Issue: 145(7), P. 3915 - 3925

Published: Feb. 10, 2023

The straightforward construction of stereogenic centers bearing unprotected functional groups, as in nature, has been a persistent pursuit synthetic chemistry. Abundant applications free enantioenriched allyl alcohol and hydroxylamine motifs have made the asymmetric hydration hydroaminoxylation conjugated dienes from water hydroxylamine, respectively, intriguing efficient routes that have, however, unachievable thus far. A fundamental challenge is failure to realize transition-metal-catalyzed enantioselective C–O bond constructions via hydrofunctionalization dienes. Here, we perform comprehensive study toward stereoselective formal by synthesizing set new P,N-ligands identifying an aryl-derived oxime surrogate for both hydroxylamine. Asymmetric hydroalkoxylation with also elucidated. Furthermore, versatile derivatizations following provide indirect but concise hydrophenoxylation, hydrofluoroalkoxylation, hydrocarboxylation unreported Finally, ligand-to-ligand hydrogen transfer process proposed based on results preliminary mechanistic experiments.

Language: Английский

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Enantioselective Coupling of Dienes and Phosphine Oxides

Journal of the American Chemical Society, Journal Year: 2018, Volume and Issue: 140(48), P. 16450 - 16454

Published: Nov. 19, 2018

We report a Pd-catalyzed intermolecular hydrophosphinylation of 1,3-dienes to afford chiral allylic phosphine oxides. Commodity dienes and air stable oxides couple generate organophosphorus building blocks with high enantio- regiocontrol. This method constitutes the first asymmetric dienes.

Language: Английский

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Catalytic Hydrothiolation: Regio- and Enantioselective Coupling of Thiols and Dienes

Journal of the American Chemical Society, Journal Year: 2018, Volume and Issue: 140(33), P. 10443 - 10446

Published: Aug. 9, 2018

We report a Rh-catalyzed hydrothiolation of 1,3-dienes, including petroleum feedstocks. Either secondary or tertiary allylic sulfides can be generated from the selective addition thiol to more substituted double bond diene. The catalyst tolerates wide range functional groups, and loading as low 0.1 mol %.

Language: Английский

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