A number of studies were conducted to demonstrate C-H activation for the construction of C-B bonds. Investigations revealed that the conversion of C-H bonds to C-B bonds was both thermodynamically and kinetically favorable. The reaction at a primary C-H bond of methane or a higher alkene B 2(OR)4 formed an alkylboronate ester R' -B(OR)2 and the accompanying borane H-B(OR2. The ester and the borane were formed on the basis of calculated bond energies for methylboronates and dioaborolanes. The rates of key steps along the reaction pathway for the conversion of a C-H bond in an alkane or arene to the C-B bond in an alkyl or arylboronate ester were favorable. These studies also highlighted the accessible barriers for C-H bond cleavage and B-C bond formation during the borylation of alkanes and arenes.

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C−H Activation for the Construction of C−B Bonds

Over the past decade, the most significant, conceptual advances in the field of fluorination were enabled most prominently by organo- and transition-metal catalysis. The most challenging transformation remains the formation of the parent C-F bond, primarily as a consequence of the high hydration energy of fluoride, strong metal-fluorine bonds, and highly polarized bonds to fluorine. Most fluorination reactions still lack generality, predictability, and cost-efficiency. Despite all current limitations, modern fluorination methods have made fluorinated molecules more readily available than ever before and have begun to have an impact on research areas that do not require large amounts of material, such as drug discovery and positron emission tomography. This Review gives a brief summary of conventional fluorination reactions, including those reactions that introduce fluorinated functional groups, and focuses on modern developments in the field.

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Introduction of Fluorine and Fluorine-Containing Functional Groups

3.1. C-M and X-H as Nucleophiles 1806 3.2. C-H and X-M as Nucleophiles 1809 3.2.1. C-Halogen Bond Formations 1809 3.2.2. C-O Bond Formations 1812 3.3. C-H and X-H as Nucleophiles 1812 3.3.1. C-O Bond Formations 1812 3.3.2. C-N Bond Formations 1815 4. Oxidative X-X Bond Formations between Two Nucleophiles 1819 5. Conclusions 1819 Author Information 1819 Biographies 1819 Acknowledgment 1820 References 1820

Bond Formations between Two Nucleophiles: Transition Metal Catalyzed Oxidative Cross-Coupling Reactions

Organic reactions that involve the direct functionalization of non-activated C–H bonds represent an attractive class of transformations which maximize atom- and step-economy, and simplify chemical synthesis. Due to the high stability of C–H bonds, these processes, however, have most often required harsh reaction conditions, which has drastically limited their use as tools for the synthesis of complex organic molecules. Following the increased understanding of mechanistic aspects of C–H activation gained over recent years, great strides have been taken to design and develop new protocols that proceed efficiently under mild conditions and duly benefit from improved functional group tolerance and selectivity. In this review, we present the current state of the art in this field and detail C–H activation transformations reported since 2011 that proceed either at or below ambient temperature, in the absence of strongly acidic or basic additives or without strong oxidants. Furthermore, by identifying and discussing the major strategies that have led to these improvements, we hope that this review will serve as a useful conceptual overview and inspire the next generation of mild C–H transformations.

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Mild metal-catalyzed C–H activation: examples and concepts

Chemistry of biologically important synthetic organoselenium compounds.

Catalysis by Palladium Pincer Complexes

Electrophilic Trifluoromethylation by Copper-Catalyzed Addition of CF3-Transfer Reagents to Alkenes and Alkynes

Preface CATALYSIS BY PINCER COMPLEXES: SYNTHESIS OF ESTERS, AMIDES, AND PEPTIDES Introduction and Background Bond Activatio by Metal-Ligand Cooperation Synthesis of Esters Synthesis of Amides Synthesis of Peptides from Beta-Amino Alcohols Concluding Remarks THE ROLE OF REDOX PROCESSES IN REACTIONS CATALYZED BY NICKEL AND PALLADIUM COMPLEXES WITH ANIONIC PINCER LIGANDS Introduction Pincer Complexes of Ni, Pd, and Pt in Oxidation States Different from II Catalytic Reactions Involving Redox Processes in the Pincer-Metal Framework Concluding Remarks APPENDED FUNCTIONALITY IN PINCER LIGANDS Introduction Appended Functionality Coplanar with the Pincer Chelate Appended Functionality Not Coplanar to the Pincer Chelate Future Outlook and Summary C-C, C-O, AND C-B BOND FORMATION BY PINCER COMPLEXES INCLUDING ASYMMETRIC CATALYSIS Introduction - Pros and Cons of Using Pincer Complexes in Catalysis Reaction of Imines and Isocyanoacetates C-H Functionalization of Organonitriles Reactions Involving Hypervalent Iodines Summary and Outlook NICKEL-CATALYZED CROSS-COUPLING REACTIONS Introduction Carbon-Carbon Bond-Forming Reactions Carbon-Heteroatom Bond-Forming Reactions Summary and Outlook PSiP TRANSITION-METAL PINCER COMPLEXES: SYNTHESIS, BOND ACTIVATION, AND CATALYSIS Introduction PSiP Ligand Syntheses Group 8 Metal PSiP Chemistry Group 9 Metal PSiP Chemistry Group 10 Metal PSiP Chemistry Group 11 Metal PSiP Chemistry Alternative Silyl Pincers Summary ELECTRONIC STRUCTURES OF REDUCED MANGANESE, IRON, AND COBALT COMPLEXES BEARING REDOX-ACTIVE BIS(IMINO)PYRIDINE PINCER LIGANDS Introduction Reduced Manganese, Iron, and Cobalt Complexes with Redox-Active Bis(imino)pyridines Conclusions and Outlook PINCER COMPLEXES WITH SATURATED FRAMEWORKS: SYNTHESIS AND APPLICATIONS Introduction Synthesis of the Ligands Synthesis and Coordination Behavior of Carbometallated PC(sp3)P Complexes Reactivity and Catalytic Applications of PC(sp3) Complexes HEAVIER GROUP 14 ELEMENTS-BASED PINCER COMPLEXES IN CATALYTIC SYNTHETIC TRANSFORMATIONS OF UNSATURATED HYDROCARBONS Introduction Synthesis of Palladium Complexes Bearing PXP-Pincer Ligands (X=Si, Ge, Sn) Hydrocarboxylation Reductive Aldol Type Reaction Dehydrogenative Borylation Synthesis and Reaction of n2-(Si-H)Pd(0) Complex as an Equivalent to PSiP-Palladium Hydride Complexes Conclusions EXPERIMENTAL AND THEORETICAL ASPECTS OF PALLADIUM PINCER-CATALYZED C-C CROSS-COUPLING REACTIONS C-C Cross-Coupling Reactions - An Indispensable Tool for the Synthesis of Complex Organic Molecules Palladium Pincer Complexes as C-C Cross-Coupling Catalysts The Role of Palladium Pincer Complexes in Heck Reactions Computational Investigations on the Thermal Feasibility of PdII/PdIV Cycles of Palladium Pincer-Catalyzed Heck Reactions Theoretical Investigations on a Pincer-Catalyzed Negishi Cross-Coupling Reaction Concluding Remarks REACTIONS OF SQUARE-PLANAR d8 PINCER COMPLEXES WITH OXYGEN AN HYDROGEN Introduction Insertion of Molecular Oxygen into Late-Transition Metal Hydride Bonds Hydrogenolysis of Late-Transition Metal Hydroxide and Alkoxide Complexes Summary Index

Pincer and pincer-type complexes : applications in organic synthesis and catalysis

In this Perspective we will highlight the most important recent breakthroughs in selective allylboron chemistry (both the synthesis and application of these species). In addition we will provide an outlook toward the future of this promising subfield of organic synthesis.

http://pubs.acs.org/doi/pdf/10.1021/jacs.6b10017

Kálmán J. Szabó

Papers

Catalysis by Palladium Pincer Complexes

Electrophilic Trifluoromethylation by Copper-Catalyzed Addition of CF3-Transfer Reagents to Alkenes and Alkynes

Pincer and pincer-type complexes : applications in organic synthesis and catalysis

Recent Advances in the Preparation and Application of Allylboron Species in Organic Synthesis

Evidence for a ruthenium dihydride species as the active catalyst in the RuCl2(PPh3)-catalyzed hydrogen transfer reaction in the presence of base