Transition-Metal-Mediated Direct C–H Amination of Hydrocarbons with Amine Reactants: The Most Desirable but Challenging C–N Bond-Formation Approach

ACS Catalysis, Journal Year: 2016, Volume and Issue: 6(4), P. 2341 - 2351

Published: Feb. 25, 2016

Cross-dehydrogenative couplings (CDCs) have become one of the most straightforward protocols in C–H bond functionalizations, showing step- and atom-efficiency without need prefunctionalization substrates reactants. However, catalytic amination procedures based on CDC strategy by employing amine reactants are considered to be challenging mainly due highly nucleophilic character parent amines inhibit turnovers difficulty optimizing proper oxidative conditions. In spite these concerns, recent efforts led notable advances procedures, particularly intermolecular reaction system. this Perspective, we address achievements transition-metal-mediated reactions with two types hydrocarbon substrates: (i) direct acidic bonds (ii) chelation-assisted amination/amidation nonacidic bonds. Mechanistic aspects also briefly delineated representative provide insights for future development practical more environmentally benign processes.

Language: Английский

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Dirhodium-catalyzed C-H arene amination using hydroxylamines

Science, Journal Year: 2016, Volume and Issue: 353(6304), P. 1144 - 1147

Published: Sept. 8, 2016

Primary and N -alkyl arylamine motifs are key functional groups in pharmaceuticals, agrochemicals, materials, as well bioactive natural products. However, there is a dearth of generally applicable methods for the direct replacement aryl hydrogens with NH 2 /NH(alkyl) moieties. Here, we present mild dirhodium-catalyzed C-H amination conversion structurally diverse monocyclic fused aromatics to corresponding primary arylamines using /NH(alkyl)- O -(sulfonyl)hydroxylamines aminating agents; relatively weak RSO O-N bond functions an internal oxidant. The methodology operationally simple, scalable, fast at or below ambient temperature, furnishing moderate-to-good yields good regioselectivity. It can be readily extended synthesis -heterocycles.

Language: Английский

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Oxazolinyl-Assisted C–H Amidation by Cobalt(III) Catalysis

ACS Catalysis, Journal Year: 2015, Volume and Issue: 6(2), P. 793 - 797

Published: Dec. 22, 2015

Cobalt-catalyzed C–H activation by means of oxazolinyl assistance set the stage for versatile direct amidations with ample substrate scope. Thus, a high-valent cobalt(III) catalyst enabled excellent levels positional and chemo-selectivities. Mechanistic studies provided strong support kinetically relevant functionalization.

Language: Английский

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Mechanism of Rhodium-Catalyzed C–H Functionalization: Advances in Theoretical Investigation

Accounts of Chemical Research, Journal Year: 2017, Volume and Issue: 50(11), P. 2799 - 2808

Published: Nov. 7, 2017

ConspectusTransition-metal-catalyzed cross-coupling has emerged as an effective strategy for chemical synthesis. Within this area, direct C–H bond transformation is one of the most efficient and environmentally friendly processes construction new C–C or C–heteroatom bonds. Over past decades, rhodium-catalyzed functionalization attracted considerable attention because versatility wide use rhodium catalysts in chemistry. A series C–X (X = C, N, O) formation reactions could be realized from corresponding bonds using catalysts. Various experimental studies on have been reported, tandem, mechanistic computational also progressed significantly.Since 2012, our group performed theoretical to reveal mechanism reactions. We studied changes oxidation state compared Rh(I)/Rh(III) catalytic cycle Rh(III)/Rh(V) density functional theory calculation. The development advanced methods improvements computing power make calculation a powerful tool study Computational able not only provide insights but explain origin regioselectivity, enantioselectivity, stereoselectivity reactions.This Account summarizes work under discussion divided into three main parts: cleavage step, C–Rh bond, regeneration active catalyst. In results four possible mechanisms, including concerted metalation–deprotonation (CMD), oxidative addition (OA), Friedel–Crafts-type electrophilic aromatic substitution (SEAr), σ-complex assisted metathesis (σ-CAM) are discussed. Subsequent example, via insertion CO, olefin, alkyne, carbene, nitrene, constructs For catalyst, reductive elimination high-valent complex protonation emphasized potential candidates. detailing reaction pathway, regioselectivity diastereoselectivity commented upon Account. selectivity clarified through analysis. Furthermore, we summarize compare along complete pathway. described demonstrates that catalysis might proceed Rh(I)/Rh(III), Rh(II)/Rh(IV), Rh(III)/Rh(V), non-redox-Rh(III) cycles.

Language: Английский

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Anthranil: An Aminating Reagent Leading to Bifunctionality for Both C(sp³)−H and C(sp²)−H under Rhodium(III) Catalysis

Angewandte Chemie International Edition, Journal Year: 2016, Volume and Issue: 55(30), P. 8696 - 8700

Published: April 28, 2016

Abstract Previous direct C−H nitrogenation suffered from simple amidation/amination with limited atom‐economy and is mostly to C(sp 2 )−H substrates. In this work, anthranil was designed as a novel bifunctional aminating reagent for both 3 bonds under rhodium(III) catalysis, thus affording nucleophilic aniline tethered an electrophilic carbonyl. A tridendate complex has been isolated the resting state of catalyst, DFT studies established intermediacy nitrene species.

Language: Английский

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Design and Optimization of Catalysts Based on Mechanistic Insights Derived from Quantum Chemical Reaction Modeling

Chemical Reviews, Journal Year: 2019, Volume and Issue: 119(11), P. 6509 - 6560

Published: May 8, 2019

Until recently, computational tools were mainly used to explain chemical reactions after experimental results obtained. With the rapid development of software and hardware technologies make modeling more reliable, they can now provide valuable insights even become predictive. In this review, we highlighted several studies involving predictions unexpected reactivities or providing mechanistic for organic organometallic that led improved results. Key these successful applications is an integration between theory experiment allows incorporation empirical knowledge with precise computed values. Computer already a standard tool being embraced by ever increasing group researchers, it clear its utility in predictive reaction design will increase further near future.

Language: Английский

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Rhodium(III)‐Catalyzed Amidation of Unactivated C(sp³)H Bonds

Angewandte Chemie, Journal Year: 2015, Volume and Issue: 127(44), P. 13241 - 13244

Published: Sept. 7, 2015

Abstract Nitrogenation by direct functionalization of CH bonds represents an important strategy for constructing CN bonds. Rhodium(III)‐catalyzed amidation unactivated C(sp 3 )H is rare, especially under mild reaction conditions. Herein, a broad scope are amidated rhodium catalysis in high efficiency using 3‐substituted 1,4,2‐dioxazol‐5‐ones as the amide source. The protocol broadens rhodium(III)‐catalyzed activation chemistry, and applicable to late‐stage natural products.

Language: Английский

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Overcoming the Limitations of C−H Activation with Strongly Coordinating N‐Heterocycles by Cobalt Catalysis

Angewandte Chemie International Edition, Journal Year: 2016, Volume and Issue: 55(35), P. 10386 - 10390

Published: July 21, 2016

Abstract Strongly coordinating nitrogen heterocycles, including pyrimidines, oxazolines, pyrazoles, and pyridines, were fully tolerated in cobalt‐catalyzed C−H amidations by imidate assistance. Structurally complex quinazolines are thus accessible a step‐economic manner. Our findings also establish the relative powers of directing groups cobalt(III)‐catalyzed functionalization for first time.

Language: Английский

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Cationic Cobalt(III)‐Catalyzed Aryl and Alkenyl CH Amidation: A Mild Protocol for the Modification of Purine Derivatives

Chemistry - A European Journal, Journal Year: 2015, Volume and Issue: 21(46), P. 16395 - 16399

Published: Sept. 29, 2015

Abstract A cationic cobalt(III)‐catalyzed direct CH amidation of unactivated (hetero)arenes and alkenes by using 1,4,2‐dioxazol‐5‐ones as the amidating reagent has been developed. This transformation proceeds efficiently under external oxidant‐free conditions with a broad substrate scope. Moreover, 6‐arylpurine compounds, which often exhibit high potency in antimycobacterial, cytostatic, anti‐HCV activities, can be smoothly amidated, thus offering mild protocol for their late stage functionalization.

Language: Английский

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Co(III)-Catalyzed Synthesis of Quinazolines via C–H Activation of N-Sulfinylimines and Benzimidates

Organic Letters, Journal Year: 2016, Volume and Issue: 18(6), P. 1306 - 1309

Published: March 8, 2016

C–H activation of arenes has been established as an important strategy for heterocycle synthesis via annulations between and unsaturated coupling partners. However, nitriles failed to act such a partner. Dioxazolones have employed synthon nitriles, subsequent with N-sulfinylimines benzimidates bearing functionalizable directing group provided facile access two classes quinazolines under Co(III)-catalysis.

Language: Английский

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