3d Transition Metals for C–H Activation

Chemical Reviews, Journal Year: 2018, Volume and Issue: 119(4), P. 2192 - 2452

Published: Nov. 27, 2018

C–H activation has surfaced as an increasingly powerful tool for molecular sciences, with notable applications to material crop protection, drug discovery, and pharmaceutical industries, among others. Despite major advances, the vast majority of these functionalizations required precious 4d or 5d transition metal catalysts. Given cost-effective sustainable nature earth-abundant first row metals, development less toxic, inexpensive 3d catalysts gained considerable recent momentum a significantly more environmentally-benign economically-attractive alternative. Herein, we provide comprehensive overview on until summer 2018.

Language: Английский

---

A comprehensive overview of directing groups applied in metal-catalysed C–H functionalisation chemistry

Chemical Society Reviews, Journal Year: 2018, Volume and Issue: 47(17), P. 6603 - 6743

Published: Jan. 1, 2018

The present review is devoted to summarizing the recent advances (2015-2017) in field of metal-catalysed group-directed C-H functionalisation. In order clearly showcase molecular diversity that can now be accessed by means directed functionalisation, whole organized following directing groups installed on a substrate. Its aim comprehensive reference work, where specific group easily found, together with transformations which have been carried out it. Hence, primary format this schemes accompanied concise explanatory text, are ordered sections according their chemical structure. feature typical substrates used, products obtained as well required reaction conditions. Importantly, each example commented respect most important positive features and drawbacks, aspects such selectivity, substrate scope, conditions, removal, greenness. targeted readership both experts functionalisation chemistry (to provide overview progress made last years) and, even more so, all organic chemists who want introduce way thinking for design straightforward, efficient step-economic synthetic routes towards molecules interest them. Accordingly, should particular also scientists from industrial R&D sector. overall goal promote application reactions outside research dedicated method development establishing it valuable archetype contemporary R&D, comparable role cross-coupling play date.

Language: Английский

---

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

---

(Pentamethylcyclopentadienyl)cobalt(III)‐Catalyzed C–H Bond Functionalization: From Discovery to Unique Reactivity and Selectivity

Advanced Synthesis & Catalysis, Journal Year: 2017, Volume and Issue: 359(8), P. 1245 - 1262

Published: March 16, 2017

Abstract High‐valent (pentamethylcyclopentadienyl)cobalt(III) [Cp*Co(III)] catalysts were found as inexpensive alternatives to (pentamethylcyclopentadienyl)rhodium(III) [Cp*Rh(III)] in the field of C—H bond functionalization, and applied a variety transformations. In this review, after discovery early examples Cp*Co(III)‐catalyzed functionalization are summarized, unique reactivity selectivity Cp*Co(III) differences between cobalt rhodium catalysis intensively discussed. Such assumed be caused by lower electronegativity, hard nature, smaller ionic radius cobalt. magnified image

Language: Английский

---

Diverse ortho-C(sp²)–H Functionalization of Benzaldehydes Using Transient Directing Groups

Journal of the American Chemical Society, Journal Year: 2016, Volume and Issue: 139(2), P. 888 - 896

Published: Dec. 25, 2016

Pd-catalyzed C–H functionalizations promoted by transient directing groups remain largely limited to arylation only. Herein, we report a diverse set of ortho-C(sp2)–H benzaldehyde substrates using the group strategy. Without installing any auxiliary group, Pd(II)-catalyzed arylation, chlorination, bromination, and Ir(III)-catalyzed amidation, could be achieved on substrates. The formed in situ via imine linkage can override other coordinating functional capable activation or catalyst poisoning, significantly expanding scope for metal-catalyzed functionalization benzaldehydes. utility this approach is demonstrated through multiple applications, including late-stage diversification drug analogue.

Language: Английский

---

Cross‐Coupling of α‐Carbonyl Sulfoxonium Ylides with C−H Bonds

Angewandte Chemie International Edition, Journal Year: 2017, Volume and Issue: 56(42), P. 13117 - 13121

Published: Aug. 29, 2017

Abstract The functionalization of carbon–hydrogen bonds in non‐nucleophilic substrates using α‐carbonyl sulfoxonium ylides has not been so far investigated, despite the potential safety advantages that such reagents would provide over either diazo compounds or their situ precursors. Described herein are cross‐coupling reactions with C(sp 2 )−H arenes and heteroarenes presence a rhodium catalyst. reaction proceeds by succession C−H activation, migratory insertion ylide into carbon–metal bond, protodemetalation, last step being turnover‐limiting. method is applied to synthesis benz[c]acridines when allied an iridium‐catalyzed dehydrative cyclization.

Language: Английский

---

C–H functionalization by high-valent Cp*Co(iii) catalysis

Chemical Communications, Journal Year: 2017, Volume and Issue: 53(22), P. 3165 - 3180

Published: Jan. 1, 2017

Significant progress has been accomplished in directed C–H functionalization through the use of earth-abundant and inexpensive first-row transition metals.

Language: Английский

---

Diazo Compounds: Versatile Synthons for the Synthesis of Nitrogen Heterocycles via Transition Metal‐Catalyzed Cascade C–H Activation/Carbene Insertion/Annulation Reactions

Advanced Synthesis & Catalysis, Journal Year: 2018, Volume and Issue: 361(5), P. 919 - 944

Published: Nov. 27, 2018

Abstract This review covers some unique diazo compounds, the coupling partners to access various versatile functionalized nitrogen heterocycles, such as indoles, indolines, isoquinolines, isoquinolones, and so on. Different transition metals (such Rh, Pd, Ru, Ir, Cu, Co) are involved in these transformations, which involve consecutive processes: metal‐catalyzed cascade C–H activation/carbene insertion/intramolecular annulation. magnified image

Language: Английский

---

Cobalt‐Catalyzed C−H Thiolation through Dehydrogenative Cross‐Coupling

Angewandte Chemie International Edition, Journal Year: 2016, Volume and Issue: 55(37), P. 11287 - 11291

Published: July 20, 2016

Abstract A cobalt‐catalyzed dehydrogenative cross‐coupling of thiols and indoles is reported. Using a cooperative reaction system, new mode action for the C−heteroatom bond formation was found. The directed C−H activation catalysis overrides an undirected thiolation indole in 3‐position that occurs absence cobalt. Mechanistic studies indicate sequence activation, thiolate transfer, reductive elimination.

Language: Английский

---

Direct Functionalization of C−H Bonds by Iron, Nickel, and Cobalt Catalysis

Chemistry - A European Journal, Journal Year: 2017, Volume and Issue: 23(39), P. 9206 - 9232

Published: June 7, 2017

Abstract Non‐precious‐metal‐catalyzed reactions are of increasing importance in chemistry due to the outstanding ecological and economic properties these metals. In subfield metal‐catalyzed direct C−H functionalization reactions, recent years have shown an number publications dedicated this topic. Nickel, cobalt, last but not least iron, started enter a field which was long dominated by precious metals such as palladium, rhodium, ruthenium, iridium. The present review article summarizes development iron‐, nickel‐, cobalt‐catalyzed until end 2016, discusses scope limitations transformations.

Language: Английский

---