Transition-Metal-Catalyzed Cross-Couplings through Carbene Migratory Insertion

Chemical Reviews, Journal Year: 2017, Volume and Issue: 117(23), P. 13810 - 13889

Published: Nov. 1, 2017

Transition-metal-catalyzed cross-coupling reactions have been well-established as indispensable tools in modern organic synthesis. One of the major research goals area is expanding scope coupling partners. In past decade, diazo compounds (or their precursors N-tosylhydrazones) emerged nucleophilic partners C-C single bond or C═C double formations transition-metal-catalyzed reactions. This type reaction involves following general steps. First, organometallic species generated by various processes, including oxidative addition, transmetalation, cyclization, cleavage, and C-H activation. Subsequently, reacts with substrate to generate metal carbene intermediate, which undergoes rapid migratory insertion form a bond. The new from may undergo transformations. carbene-based has proven be general: transition metals Pd, Cu, Rh, Ni, Co, Ir are effective catalysts; also extended substrates other than compounds; cascade processes devised based on insertion. review will summarize achievements made this field since 2001.

Language: Английский

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Recent progress on donor and donor–donor carbenes

Chemical Society Reviews, Journal Year: 2020, Volume and Issue: 49(3), P. 908 - 950

Published: Jan. 1, 2020

This review highlights the recent advances in donor and donor–donor carbenes.

Language: Английский

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Metal–Metal Bonds in Catalysis

ACS Catalysis, Journal Year: 2016, Volume and Issue: 7(2), P. 936 - 958

Published: Dec. 9, 2016

Transition metals can assemble to form multinuclear complexes by engaging in direct metal-to-metal interactions. Metal–metal covalent bonds provide a large perturbation electronic structure, relative mononuclear metal ions, and the unique properties of these dinuclear fragments be harnessed broad range applications—for example, as chromophores photochemical processes, redox centers molecular electronics, or structural elements metal–organic materials. There is growing body evidence that metal–metal may also formed under conditions relevant catalysis play key role transformations were previously assumed only involve species. These findings have stimulated interest characterizing reaction pathways developing well-defined platforms catalytic active sites. In this Perspective, we present case studies emerging area research, emphasizing impact bonding either enhancing depressing rate and/or selectivity organic transformation.

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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Bimetallic cooperation across the periodic table

Nature Reviews Chemistry, Journal Year: 2020, Volume and Issue: 4(12), P. 696 - 702

Published: Oct. 8, 2020

Language: Английский

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Transition Metal Catalyzed Insertion Reactions with Donor/Donor Carbenes

Angewandte Chemie International Edition, Journal Year: 2020, Volume and Issue: 60(13), P. 6864 - 6878

Published: Aug. 8, 2020

Donor/donor carbenes are relatively new in the field of carbene chemistry; although applications C-H and X-H insertion reactions few number, they demonstrate exquisite chemo- stereo-selectivity. Recent reports have shown that C-H, N-H, B-H, O-H, S-H, Si-H, Ge-H, Sn-H P-H feasible with a variety transition metal catalysts, both inter- intramolecularly. Furthermore, high degrees diastereo- enantioselectivity been observed several cases. Methods typically involve formation diazo-based precursor, but procedures using diazo-free developed significant success. This Minireview covers transition-metal catalyzed donor/donor donor carbenes, providing context for future developments this emerging field.

Language: Английский

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Mechanistic snapshots of rhodium-catalyzed acylnitrene transfer reactions

Science, Journal Year: 2023, Volume and Issue: 381(6657), P. 525 - 532

Published: July 20, 2023

Rhodium (Rh) acylnitrene complexes are widely implicated in catalytic C-H amidation reactions but have eluded isolation and structural characterization. To overcome this challenge, we designed a chromophoric octahedral Rh complex with bidentate dioxazolone ligand, which photoinduced metal-to-ligand charge transfer initiates amidation. X-ray photocrystallographic analysis of the Rh-dioxazolone allowed elucidation targeted Rh-acylnitrenoid provided firm evidence that singlet nitrenoid species is primarily responsible for acylamino reactions. We also monitored crystallo reaction nucleophile situ-generated Rh-acylnitrenoid, crystallographically traceable system to capture mechanistic snapshots transfer.

Language: Английский

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[4+2] or [4+1] Annulation: Changing the Reaction Pathway of a Rhodium‐Catalyzed Process by Tuning the Cp Ligand

Angewandte Chemie International Edition, Journal Year: 2017, Volume and Issue: 56(9), P. 2408 - 2412

Published: Jan. 23, 2017

Abstract A change in reaction pathway was achieved for the first time by tuning cyclopentadienyl (Cp) ligand used rhodium‐catalyzed cyclization of benzamides with conjugated enynones. Depending on Cp ligand, switched between [4+2] and [4+1] annulation. Electronic effects turned out to be crucial product distribution. The dichotomy attributed alteration Lewis acidity resultant Cp‐bound rhodium species.

Language: Английский

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Half-Sandwich Ruthenium Carbene Complexes Linktrans-Hydrogenation andgem-Hydrogenation of Internal Alkynes

Journal of the American Chemical Society, Journal Year: 2018, Volume and Issue: 140(8), P. 3156 - 3169

Published: Feb. 11, 2018

The hydrogenation of internal alkynes with [Cp*Ru]-based catalysts is distinguished by an unorthodox stereochemical course in that E-alkenes are formed trans-delivery the two H atoms H2. A combined experimental and computational study now provides a comprehensive mechanistic picture: metallacyclopropene (η2-vinyl complex) primarily formed, which either evolves into E-alkene via concerted process or reacts to give half-sandwich ruthenium carbene; this case, one C starting alkyne converted methylene group. This transformation represents formal gem-hydrogenation π-bond, has hardly any precedent. barriers for trans-hydrogenation similar: whereas DFT predicts preference trans-hydrogenation, CCSD(T) finds slightly more facile. carbene, once will bind second H2 molecule evolve desired E-alkene, positional alkene isomer corresponding alkane; associative pathway explains why double bond isomerization over-reduction compete trans-hydrogenation. computed scenario concurs para-hydrogen-induced polarization transfer (PHIP) NMR data, confirm direct H2, formation carbene intermediates gem-hydrogenation, their evolution product side products alike. Propargylic −OR (R = H, Me) groups exert strong directing stabilizing effect, such several could be isolated characterized X-ray diffraction. gathered information spurred significant preparative advances: specifically, highly selective trans-hydrogenations propargylic alcohols reported, compatible many other reducible functional groups. Moreover, ability generate metal carbenes paved way noncanonical hydrogenative cyclopropanations, ring expansions, cycloadditions.

Language: Английский

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Rhodium‐Catalyzed Geminal Oxyfluorination and Oxytrifluoro‐Methylation of Diazocarbonyl Compounds

Angewandte Chemie International Edition, Journal Year: 2016, Volume and Issue: 55(29), P. 8410 - 8415

Published: May 24, 2016

Abstract A new reaction for the rhodium‐catalyzed geminal‐difunctionalization‐based fluorination is presented. The substrates are aromatic and aliphatic diazocarbonyl compounds. As fluorine source a stable easily accessible benziodoxole reagent was used. variety of alcohol, phenol, carboxylic acid reagents were employed to introduce second functionality. extended trifluoromethylation using benziodoxolon reagent. reactions probably proceed by rhodium‐containing onium ylide type intermediate, which trapped either F or CF 3 electrophiles.

Language: Английский

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