scholarly journals Tandem C–O and C–H Activation at Palladium Enables Catalytic Direct C–H Alkenylation with Enol Pivalates

2021 ◽  
Author(s):  
Nahiane Pipaon Fernandez ◽  
Gregory Gaube ◽  
Kyla Woelk ◽  
Mathias Burns ◽  
David Leitch
Keyword(s):  
Bond Activation ◽  
Bond Formation ◽  
Palladium Catalysis ◽  
Oxidative Addition ◽  
Cross Coupling ◽  
Addition Product ◽  
Pivalic Acid ◽  
Mechanistic Studies ◽  
Limiting Step ◽  
Strong Bond Activation

The use of oxygen-based electrophiles in cross-coupling remains challenging for substrates with strong C–O bonds, with few examples that can combine C–O activation with an-other strong-bond activation in tandem. We report the first example of a direct, tandem C–O/C–H activation approach to C–C bond formation using palladium catalysis. This reaction combines C–O oxidative addition at enol pivalates with con-certed metallation deprotonation of functionalized heterocycles to achieve base-free direct C–H alkenylation, with pivalic acid as the only byproduct. Mechanistic studies reveal that the Pd(II) C–O oxidative addition product is the major catalyst resting state, indicating that C–H activation is the turnover-limiting step.

Design and Development of Fe-Catalyzed Intra- and Intermolecular Carbofunctionalization of Vinyl Cyclopropanes

2019 ◽  
Author(s):  
Lei Liu ◽  
Wes Lee ◽  
Mingbin Yuan ◽  
Chris Acha ◽  
Michael B. Geherty ◽  
...  
Keyword(s):  
Bond Formation ◽  
Cross Coupling ◽  
Alkyl Halides ◽  
Grignard Reagents ◽  
Mechanistic Studies ◽  
Radical Intermediates ◽  
Design And Implementation ◽  
Solvent Cage ◽  
Radical Cascade ◽  
Radical Processes

Design and implementation of the first (asymmetric) Fe-catalyzed intra- and intermolecular difunctionalization of vinyl cyclopropanes (VCPs) with alkyl halides and aryl Grignard reagents has been realized via a mechanistically driven approach. Mechanistic studies support the diffusion of the alkyl radical intermediates out of the solvent cage to participate in an intra- or -intermolecular radical cascade with the VCP followed by re-entering the Fe radical cross-coupling cycle to undergo selective C(sp2)-C(sp3) bond formation. Overall, we provide new design principles for Fe-mediated radical processes and underscore the potential of using combined computations and experiments to accelerate the development of challenging transformations.

Photoinduced Oxidative Cross-Coupling for O–S Bond Formation: A Facile Synthesis of Alkyl Benzenesulfonates

Synlett ◽  
2017 ◽  
Vol 28 (13) ◽  
pp. 1558-1563 ◽  
Author(s):  
Aiwen Lei ◽  
Atul Singh ◽  
Hong Yi ◽  
Guoting Zhang ◽  
Changliang Bian ◽  
...  
Keyword(s):  
Visible Light ◽  
Bond Formation ◽  
Cross Coupling ◽  
Selective Synthesis ◽  
Mechanistic Studies ◽  
Facile Synthesis ◽  
Metal Free

We have developed a photoinduced oxidative cross-coupling of thiophenols with alcohols for O–S bond formation. The protocol uses visible light, a metal-free photocatalyst, and oxygen as the oxidant for the selective synthesis of alkyl benzenesulfonates; no ligand co-additive is necessary. Mechanistic studies suggested that the disulfide and alkyl benzenesulfinate are involved as intermediates and that the transformation proceeds by a radical pathway.

scholarly journals Pd-catalyzed intramolecular addition of active methylene compounds to alkynes with subsequent cross-coupling with (hetero)aryl halides

RSC Advances ◽  
2019 ◽  
Vol 9 (68) ◽  
pp. 40152-40167 ◽  
Author(s):  
Aleksandra Błocka ◽  
Paweł Woźnicki ◽  
Marek Stankevič ◽  
Wojciech Chaładaj
Keyword(s):  
Functional Group ◽  
Cross Coupling ◽  
Aryl Halides ◽  
Mechanistic Studies ◽  
Rate Limiting Step ◽  
Limiting Step ◽  
Active Methylene Compounds ◽  
Tandem Cyclization ◽  
Rate Limiting ◽  
Active Methylene

A tandem cyclization/coupling of acetylenic active methylene compounds with aryl halides features broad scope and excellent functional group compatibility. Mechanistic studies identified 5-exo-dig cyclization as the rate limiting step.

scholarly journals Catalytic Benzolactamization Through Isonitrile Insertion Enabled 1,4-Palladium Shift

2021 ◽  
Author(s):  
Fulin Zhang ◽  
Ruihua Zhao ◽  
Lei Zhu ◽  
Yinghua Yu ◽  
Saihu Liao ◽  
...  
Keyword(s):  
Reaction Mechanism ◽  
Heterocyclic Compounds ◽  
Bond Activation ◽  
Bond Formation ◽  
Bioactive Molecules ◽  
Mechanistic Studies ◽  
Carbon And Nitrogen ◽  
New Methods ◽  
Novel Approach ◽  
Bicyclic System

<b>Isoindolinone is a class of versatile <i>N</i>-heterocycles embedded in many bioactive molecules and natural products. The invention of new methods to synthesize these heterocyclic compounds with easily accessible chemicals is always attractive. Herein, a conceptually novel approach to access this bicyclic system via isonitrile insertion enabled 1,4-pallaidum shift is described. Compared with conventional isonitrile participated C-H bond activation, both carbon and nitrogen atoms in isonitrile moiety are engaged in new bond formation. Notably, two different isoindolinones can be obtained selectively by switching the bases employed. Mechanistic studies including DFT calculations have shed lights on the reaction mechanism and explained the selectivity led to different products. Moreover, the power of current benzolactamization is further demonstrated by providing concise routes to key intermediates of indoprofen, indobufen, aristolactams, lennoxamine and falipamil.</b>

Deoxygenative Transition-Metal-Promoted Reductive Coupling and Cross-Coupling of Alcohols and Epoxides

Synthesis ◽  
2020 ◽  
Vol 53 (02) ◽  
pp. 267-278
Author(s):  
Kenneth M. Nicholas ◽  
Chandrasekhar Bandari
Keyword(s):  
Transition Metal ◽  
Bond Activation ◽  
Bond Formation ◽  
Cross Coupling ◽  
Transition Metal Catalysts ◽  
Coupling Reactions ◽  
Reductive Coupling ◽  
Practical Applications ◽  
Cross Coupling Reactions ◽  
Carbon Carbon Bond

AbstractThe prospective utilization of abundant, CO2-neutral, renewable feedstocks is driving the discovery and development of new reactions that refunctionalize oxygen-rich substrates such as alcohols and polyols through C–O bond activation. In this review, we highlight the development of transition-metal-promoted reactions of renewable alcohols and epoxides that result in carbon–carbon bond-formation. These include reductive self-coupling reactions and cross-coupling reactions of alcohols with alkenes and arene derivatives. Early approaches to reductive couplings employed stoichiometric amounts of low-valent transition-metal reagents to form the corresponding hydrocarbon dimers. More recently, the use of redox-active transition-metal catalysts together with a reductant has enhanced the practical applications and scope of the reductive coupling of alcohols. Inclusion of other reaction partners with alcohols such as unsaturated hydrocarbons and main-group organometallics has further expanded the diversity of carbon skeletons accessible and the potential for applications in chemical synthesis. Catalytic reductive coupling and cross-coupling reactions of epoxides are also highlighted. Mechanistic insights into the means of C–O activation and C–C bond formation, where available, are also highlighted.1 Introduction2 Stoichiometric Reductive Coupling of Alcohols3 Catalytic Reductive Coupling of Alcohols3.1 Heterogeneous Catalysis3.2 Homogeneous Catalysis4 Reductive Cross-Coupling of Alcohols4.1 Reductive Alkylation4.2 Reductive Addition to Olefins5 Epoxide Reductive Coupling Reactions6 Conclusions and Future Directions

Synthesis of Benzamide Derivatives by the Reaction of Arenes and Isocyanides through a C–H Bond Activation Strategy

Synlett ◽  
2017 ◽  
Vol 29 (01) ◽  
pp. 94-98 ◽  
Author(s):  
Mehdi Khalaj ◽  
Mahboubeh Taherkhani ◽  
Seyed Mousavi-Safavi ◽  
Jafar Akbari
Keyword(s):  
Bond Activation ◽  
Bond Formation ◽  
Cross Coupling ◽  
Aryl Halides ◽  
Coupling Reactions ◽  
Benzene Derivatives ◽  
Formation Reaction ◽  
Cross Coupling Reactions ◽  
Carbon Carbon Bond ◽  
Benzamide Derivatives

A carbon–carbon bond formation reaction between isocyanides and benzene derivatives is reported. In contrast to traditional cross-coupling reactions, which require aryl halides or pseudohalides, we use a palladium catalyst to generate the aryl–palladium through C–H bond activation of arenes. This method offers an attractive approach to a range of benzamides from readily accessible benzene derivatives.

scholarly journals Pd(quinox)-catalyzed allylic relay Suzuki reactions of secondary homostyrenyl tosylates via alkene-assisted oxidative addition

2014 ◽  
Vol 5 (6) ◽  
pp. 2336-2339 ◽  
Author(s):  
Benjamin J. Stokes ◽  
Amanda J. Bischoff ◽  
Matthew S. Sigman
Keyword(s):  
Oxidative Addition ◽  
Cross Coupling ◽  
Mechanistic Studies ◽  
Suzuki Reactions

Pd(quinox)-catalyzed relay Suzuki reactions of secondary homostyrenyl tosylates are highly selective for allylic cross-coupling products. Mechanistic studies suggest that alkene precoordination enables a chelation-controlled oxidative addition.

scholarly journals Catalytic Benzolactamization Through Isonitrile Insertion Enabled 1,4-Palladium Shift

2021 ◽  
Author(s):  
Fulin Zhang ◽  
Ruihua Zhao ◽  
Lei Zhu ◽  
Yinghua Yu ◽  
Saihu Liao ◽  
...  
Keyword(s):  
Reaction Mechanism ◽  
Heterocyclic Compounds ◽  
Bond Activation ◽  
Bond Formation ◽  
Bioactive Molecules ◽  
Mechanistic Studies ◽  
Carbon And Nitrogen ◽  
New Methods ◽  
Novel Approach ◽  
Bicyclic System

<b>Isoindolinone is a class of versatile <i>N</i>-heterocycles embedded in many bioactive molecules and natural products. The invention of new methods to synthesize these heterocyclic compounds with easily accessible chemicals is always attractive. Herein, a conceptually novel approach to access this bicyclic system via isonitrile insertion enabled 1,4-pallaidum shift is described. Compared with conventional isonitrile participated C-H bond activation, both carbon and nitrogen atoms in isonitrile moiety are engaged in new bond formation. Notably, two different isoindolinones can be obtained selectively by switching the bases employed. Mechanistic studies including DFT calculations have shed lights on the reaction mechanism and explained the selectivity led to different products. Moreover, the power of current benzolactamization is further demonstrated by providing concise routes to key intermediates of indoprofen, indobufen, aristolactams, lennoxamine and falipamil.</b>

Air-stable phosphine oxides as preligands for catalytic activation reactions of C-Cl, C-F, and C-H bonds

2006 ◽  
Vol 78 (2) ◽  
pp. 209-214 ◽  
Author(s):  
Lutz Ackermann ◽  
Robert Born ◽  
Julia H. Spatz ◽  
Andreas Althammer ◽  
Christian J. Gschrei
Keyword(s):  
Bond Activation ◽  
Bond Formation ◽  
Cross Coupling ◽  
Coupling Reactions ◽  
Phosphine Oxides ◽  
Aryl Chlorides ◽  
Catalytic Activation ◽  
Cross Coupling Reactions ◽  
Palladium Catalyzed ◽  
Metal Catalyzed

Studies on the use of easily accessible heteroatom-substituted secondary phosphine oxides as preligands for cross-coupling reactions are described. These air-stable sterically hindered phosphine oxides allow for efficient palladium-catalyzed Suzuki- and nickel-catalyzed Kumada-coupling reactions using electronically deactivated aryl chlorides. In addition, they enable nickel-catalyzed coupling reactions of magnesium organyls with aryl fluorides at ambient temperature, and ruthenium-catalyzed coupling reactions of aryl chlorides via C-H bond activation. Finally, the application of modular diamino phosphine chlorides as preligands for a variety of transition-metal-catalyzed C-C and C-N bond formation reactions employing electron-rich aryl chlorides is presented.

Ni-Catalyzed Deamination Cross-Electrophile Coupling of Katritzky Salts with Halides via C–N Bond Activation

2019 ◽  
Author(s):  
Shengyang Ni ◽  
Chunxiao Li ◽  
Jianlin Han ◽  
Yu Mao ◽  
Yi Pan
Keyword(s):  
Bond Activation ◽  
Bond Formation ◽  
Coupling Reaction ◽  
Cross Coupling ◽  
One Pot ◽  
Aryl Iodide ◽  
Cross Coupling Reaction ◽  
New Strategy ◽  
The Cross

This work describes the first Ni-catalyzed cross-electrophile coupling of alkylpyridinium salts, derived from the corresponding amines, with aryl iodide, bromoalkyne or bromoalkyl coupling partners. C(sp)-C(sp<sup>3</sup>), C(sp<sup>2</sup>)-C(sp<sup>3</sup>) and C(sp<sup>3</sup>)-C(sp<sup>3</sup>) bond formation was achieved to afford a variety of synthetically useful arenes, alkynes and alkanes in good yields from<b>2</b>-<b>33</b>. The advantages of the methodology are showcased in the two-step synthesis of the key lactonic moiety of (+)-Compactin and (+)-Mevinolin from commercially available starting materials. A one-pot procedure without isolation of alkylpyridinium tetrafluoroborate salt was also demonstrated to be successful. This work represents a new strategy for the cross-coupling reaction of two electrophiles, and also provides a complementary and highly valuable vista for the current methodologies of alkyl arene/alkyne/alkane synthesis.

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