scholarly journals Ligand-Controlled Regiodivergent Palladium-Catalyzed Hydrogermylation of Ynamides

2020 ◽  
Author(s):  
Vincent Debrauwer ◽  
Aneta Turlik ◽  
Lénaïc Rummler ◽  
Alessandro Prescimone ◽  
Nicolas Blanchard ◽  
...  
Keyword(s):  
Small Molecules ◽  
Functional Group ◽  
Cross Coupling ◽  
Building Blocks ◽  
Coupling Reactions ◽  
Heterocyclic Chemistry ◽  
Cross Coupling Reactions ◽  
Palladium Catalyzed ◽  
Metal Catalyzed ◽  
Pi System

Ynamides are fascinating small molecules with complementary reactivities under radical, ionic and metal-catalyzed conditions. We report herein synthetic and DFT investigations of palladium-catalyzed ligand-controlled regiodivergent hydro-metallation reactions of ynamides. Germylated and stannylated enamides are obtained with excellent alpha,<i>E</i>- or beta,<i>E</i>-selectivities and a broad functional group tolerance. Such a regiodivergent palladium-catalyzed process is unique in ynamide chemistry and allows for the elaboration of metallated-enamides that are useful building blocks for cross-coupling reactions or heterocyclic chemistry. DFT calculations fully support the experimental data and demonstrate the crucial roles of the <i>trans</i>-geometry of the [H-Pd(L)-Ge] complex, as well as of the steric requirements of the phosphine ligand. In addition, the prevalence of a hydro-palladation pathway over a metal-palladation of the pi system of the ynamide was demonstrated.

scholarly journals Ligand-Controlled Regiodivergent Palladium-Catalyzed Hydrogermylation of Ynamides

2020 ◽  
Author(s):  
Vincent Debrauwer ◽  
Aneta Turlik ◽  
Lénaïc Rummler ◽  
Alessandro Prescimone ◽  
Nicolas Blanchard ◽  
...  
Keyword(s):  
Small Molecules ◽  
Functional Group ◽  
Cross Coupling ◽  
Building Blocks ◽  
Coupling Reactions ◽  
Heterocyclic Chemistry ◽  
Cross Coupling Reactions ◽  
Palladium Catalyzed ◽  
Metal Catalyzed ◽  
Pi System

Ynamides are fascinating small molecules with complementary reactivities under radical, ionic and metal-catalyzed conditions. We report herein synthetic and DFT investigations of palladium-catalyzed ligand-controlled regiodivergent hydro-metallation reactions of ynamides. Germylated and stannylated enamides are obtained with excellent alpha,<i>E</i>- or beta,<i>E</i>-selectivities and a broad functional group tolerance. Such a regiodivergent palladium-catalyzed process is unique in ynamide chemistry and allows for the elaboration of metallated-enamides that are useful building blocks for cross-coupling reactions or heterocyclic chemistry. DFT calculations fully support the experimental data and demonstrate the crucial roles of the <i>trans</i>-geometry of the [H-Pd(L)-Ge] complex, as well as of the steric requirements of the phosphine ligand. In addition, the prevalence of a hydro-palladation pathway over a metal-palladation of the pi system of the ynamide was demonstrated.

scholarly journals Protecting group-free, selective cross-coupling of alkyltrifluoroborates with borylated aryl bromides via photoredox/nickel dual catalysis

2015 ◽  
Vol 112 (39) ◽  
pp. 12026-12029 ◽  
Author(s):  
Yohei Yamashita ◽  
John C. Tellis ◽  
Gary A. Molander
Keyword(s):  
Small Molecules ◽  
Functional Group ◽  
Cross Coupling ◽  
Differential Protection ◽  
Coupling Reactions ◽  
Protecting Group ◽  
Cross Coupling Reactions ◽  
Aryl Bromides ◽  
Rapid Construction ◽  
Metal Catalyzed

Orthogonal reactivity modes offer substantial opportunities for rapid construction of complex small molecules. However, most strategies for imparting orthogonality to cross-coupling reactions rely on differential protection of reactive sites, greatly reducing both atom and step economies. Reported here is a strategy for orthogonal cross-coupling wherein a mechanistically distinct activation mode for transmetalation of sp3-hybridized organoboron reagents enables C-C bond formation in the presence of various protected and unprotected sp2-hybridized organoborons. This manifold has the potential for broad application, because orthogonality is inherent to the activation mode itself. The diversification potential of this platform is shown in the rapid elaboration of a trifunctional lynchpin through various transition metal-catalyzed processes without nonproductive deprotection or functional group manipulation steps.

Dual Nickel/Palladium-Catalyzed Reductive Cross-Coupling Reactions Between Two Phenol Derivatives

2020 ◽  
Author(s):  
Baojian Xiong ◽  
Yue Li ◽  
Yin Wei ◽  
Søren Kramer ◽  
Zhong Lian
Keyword(s):  
Functional Group ◽  
Low Cost ◽  
Cross Coupling ◽  
Coupling Reactions ◽  
Phenol Derivatives ◽  
Cross Coupling Reactions ◽  
Palladium Catalyzed ◽  
One Step ◽  
Aryl Tosylates ◽  
Low Sensitivity

Cross-coupling between substrates that can be easily derived from phenols is highly attractive due to the abundance and low cost of phenols. Here, we report a dual nickel/palladium-catalyzed reductive cross-coupling between aryl tosylates and aryl triflates; both substrates can be accessed in just one step from readily available phenols. The reaction has a broad functional group tolerance and substrate scope (>60 examples). Furthermore, it displays low sensitivity to steric effects demonstrated by the synthesis of a 2,2’disubstituted biaryl and a fully substituted aryl product. The widespread presence of phenols in natural products and pharmaceuticals allow for straightforward late-stage functionalization, illustrated with examples such as Ezetimibe and tyrosine. NMR spectroscopy and DFT calculations indicate that the nickel catalyst is responsible for activating the aryl triflate, while the palladium catalyst preferentially reacts with the aryl tosylate.

Stereodivergent Hydrosilylation, Hydrostannylation, and Hydrogermylation of α-Trifluoromethylated Alkynes and Their Synthetic Applications

Synthesis ◽  
2016 ◽  
Vol 48 (19) ◽  
pp. 3317-3330 ◽  
Author(s):  
Cédric Tresse ◽  
Stéphane Schweizer ◽  
Philippe Bisseret ◽  
Jacques Lalevée ◽  
Gwilherm Evano ◽  
...  
Keyword(s):  
Functional Group ◽  
Cross Coupling ◽  
Aryl Halides ◽  
Coupling Reactions ◽  
Cross Coupling Reactions ◽  
Palladium Catalyzed

Stereoselective hydrometalation reactions of aryl- and alkyl-substituted trifluoromethylated alkynes with triethylsilane, tributylstannane, and triphenylgermane have been investigated. (E)-α-CF3-Vinylsilanes, -stannanes, and -germanes were obtained under palladium-catalyzed conditions whereas the corresponding (Z)-α-CF3-vinylgermanes were obtained under radical conditions. These reactions proceed in good to excellent yields and possess a broad functional group tolerance. Applications of the (Z)- and (E)-α-CF3-vinylgermanes in palladium-catalyzed cross-coupling reactions with aryl halides having diverse electronic requirements were also investigated. The corresponding (Z)- and (E)-α-CF3-styrenes were obtained as single isomers, thus demonstrating the utility of these versatile synthons for the synthesis of stereodefined trifluoromethylated alkenes.

Directed ortho Metalation (DoM)-Linked Corriu–Kumada, Negishi, and Suzuki–Miyaura Cross-Coupling Protocols: A Comparative Study

Synthesis ◽  
2018 ◽  
Vol 50 (22) ◽  
pp. 4395-4412 ◽  
Author(s):  
Victor Snieckus ◽  
Claude Quesnelle
Keyword(s):  
Transition Metal ◽  
Comparative Study ◽  
Systematic Study ◽  
Functional Group ◽  
Cross Coupling ◽  
Coupling Reactions ◽  
Cross Coupling Reactions ◽  
Ortho Metalation ◽  
Transition Metal Catalyzed ◽  
Metal Catalyzed

A systematic study of the widely used, titled name reaction transition-metal-catalyzed cross-coupling reactions with attention to context with the directed ortho metalation (DoM) is reported. In general, the Suzuki–Miyaura and Negishi protocols show greater scope and better yields than the Corriu–Kumada variant, although the latter qualitatively proceeds at fastest rate but has low functional group tolerance. The Negishi process is shown to be useful for substrates with nucleophile and base-sensitive functionality and it is comparable to the Suzuki–Miyaura reaction in efficiency. The link of these cross-coupling reactions to the DoM strategy lends itself to the regioselective construction of diversely substituted aromatics and heteroaromatics.

Transition-Metal-Catalyzed Cross-Coupling with Non-Diazo Carbene Precursors

Synlett ◽  
2018 ◽  
Vol 30 (05) ◽  
pp. 542-551 ◽  
Author(s):  
Jianbo Wang ◽  
Kang Wang
Keyword(s):  
Transition Metal ◽  
Cross Coupling ◽  
Diazo Compounds ◽  
Coupling Reactions ◽  
Cross Coupling Reactions ◽  
Carbon Carbon Bond ◽  
Palladium Catalyzed ◽  
Fischer Carbenes ◽  
Transition Metal Catalyzed ◽  
Metal Catalyzed

Transition-metal-catalyzed cross-coupling reactions through metal carbene migratory insertion have emerged as powerful methodology for carbon–carbon bond constructions. Typically, diazo compounds (or in situ generated diazo compounds from N-tosylhydrazones) have been employed as the metal carbene precursors for this type of cross-coupling reactions. Recently, cross-coupling reactions employing non-diazo carbene precursors, such as conjugated ene-yne-ketones, allenyl ketones, alkynes, cyclopropenes, and Cr(0) Fischer carbenes, have been developed. This account will summarize our efforts in the development of transition-metal-catalyzed cross-coupling reactions with these non-diazo carbene precursors.1 Introduction2 Cross-Coupling with Ene-yne-ketones, Allenyl Ketones, and Alkynes3 Cross-Coupling Involving Ring-Opening of Cyclopropenes4 Palladium-Catalyzed Cross-Coupling with Chromium(0) Fischer Carbenes5 Conclusion

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.

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