Transition-Metal-Catalyzed C−S, C−Se, and C−Te Bond Formation via Cross-Coupling and Atom-Economic Addition Reactions

Transition metal-catalyzed direct functionalization of C–H bonds is one of the key emerging strategies that is currently attracting tremendous attention with the aim to provide alternative environmentally friendly and efficient ways for the construction of C–C and C–hetero bonds. In particular, the strategy involving regioselective C–H activation assisted by various functional groups shows high potential, and significant achievements have been made in both the development of novel reactions and the mechanistic study. In this review, we attempt to give an overview of the development of utilizing the functionalities as directing groups. The discussion is directed towards the use of different functional groups as directing groups for the construction of C–C and C–hetero bonds via C–H activation using various transition metal catalysts. The synthetic applications and mechanistic features of these transformations will be discussed, and the review is organized on the basis of the type of directing groups and the type of bond being formed or the catalyst.

Transition metal-catalyzed C–H bond functionalizations by the use of diverse directing groups

Dialkylbiaryl phosphines are a valuable class of ligand for Pd-catalyzed amination reactions and have been applied in a range of contexts. This perspective attempts to aid the reader in the selection of the best choice of reaction conditions and ligand of this class for the most commonly encountered and practically important substrate combinations.

Dialkylbiaryl phosphines in Pd-catalyzed amination: a user's guide

/pdf/chemicals-from-alkynes-with-palladium-catalysts-2z3b447mxh.pdf

Chemicals from Alkynes with Palladium Catalysts

http://pubs.acs.org/doi/pdf/10.1021/acscatal.5b00072

Nickel: The “Spirited Horse” of Transition Metal Catalysis

Organosilicon compounds act as a nucleophile upon activation by an appropriate base and behave in a manner similar to main-group organometallic reagents. In the last decades, structurally divergent organosilicon reagents are available and have become more employed for synthetic transformation with the aid of transition-metal complexes, because organosilicon compounds are in general superior to other organometallic compounds in view of stability, solubility, nontoxicity, and easy-handling. Particularly, cross-coupling of organosilicon reagents with organic halides or pseudohalides has been considered to be a useful tool for constructing the carbon frameworks of various target molecules such as pharmaceuticals and π-conjugated functional materials. Perfluoroalkylsilicon compounds such as CF3SiEt3 have found use as reagents for the metal-catalyzed introduction of perfluoroalkyl groups into many substrates. In addition, functionalized organosilicon reagents are readily accessible by catalytic approach startin...

Recent Advances in Transition-Metal-Catalyzed Synthetic Transformations of Organosilicon Reagents

Highly Chemoselective Carbon ? Carbon σ-Bond Activation: Nickel/Lewis Acid Catalyzed Polyfluoroarylcyanation of Alkynes

ConspectusOrganic synthesis based on straightforward transformations is essential for environmentally benign manufacturing for the invention of novel pharmaceuticals, agrochemicals, and organoelectronic materials in order to ultimately realize a sustainable society. Metal-catalyzed C–H bond-cleaving functionalization has become a promising method for achieving the above goal. For site-selective C–H bond cleavage, so-called directing groups, i.e., ligands attached to substrates, are employed. Commonly utilized directing groups are carbonyls, imines, carboxyls, amides, and pyridyls, which σ-donate electron pairs to metals. On the other hand, unsaturated substrates such as alkenes and alkynes, which participate largely as reactants in organic synthesis, are prepared readily by a wide variety of synthetic transformations and are also employed as reactants in organometallic chemistry. Moreover, such unsaturated groups form complexes with some metals by ligation of their p orbitals via donation and back-donatio...

Synthetic Transformations through Alkynoxy–Palladium Interactions and C–H Activation

Alkynyl aryl ethers react with internal alkynes through selective ortho C–H activation by a palladium(0) catalyst to give substituted 2-methylidene-2H-chromenes. The alkynoxy group acts as a directing group to promote ortho C–H functionalization. Deuterium-labeling experiments indicated that the arylpalladium hydride complex is a key intermediate via oxidative addition. Various functional groups tolerate the present transformation to give the corresponding products.

Palladium-catalyzed cycloaddition of alkynyl aryl ethers with internal alkynes via selective ortho C-H activation.

It's selective: The title reaction involves palladium(0)-catalyzed insertion of C≡C bonds into benzylic C(sp(3))-H bonds, thus providing efficient access to 2-methylene-2,3-dihydrobenzofurans, which transform into benzofurans upon treatment with a weak acid (e.g., AcOH) and electrophiles. The alkynoxy group serves as a directing group in promoting C-H bond functionalization.

Yasunori Minami

Papers

Recent Advances in Transition-Metal-Catalyzed Synthetic Transformations of Organosilicon Reagents

Highly Chemoselective Carbon ? Carbon σ-Bond Activation: Nickel/Lewis Acid Catalyzed Polyfluoroarylcyanation of Alkynes

Synthetic Transformations through Alkynoxy–Palladium Interactions and C–H Activation

Palladium-catalyzed cycloaddition of alkynyl aryl ethers with internal alkynes via selective ortho C-H activation.

Palladium‐Catalyzed Hydrobenzylation of ortho‐Tolyl Alkynyl Ethers by Benzylic C ? H Activation: Remarkable Alkynoxy‐Directing Effect