PdCl2(CH3CN)2-catalyzed regioselective C-H olefinations of 2-amino biaryls with vinylsilanes as unactivated alkenes

Pd Nanoparticle-Catalyzed Stereospecific Mizoroki-Heck Arylation of cis-1,2-Disilylarylethylenes

In the presence of catalytic amounts of Pd nanoparticles, generated from Pd2dba3/Ag(I), cis-1,2-ditrimethylsilylarylethylenes undergo with aryl iodides a stereospecific Mizoroki-Heck arylation leading to trans-ditrimethylsilyldiarylethylenes. This chemoselectivity is in contrast to that of their trimethylgermyl analogues, which are arylated at the position of the C-Ge bonds. trans-1,2-Ditrimethylsilylarylethylenes are completely unreactive under the standard reaction conditions. The reaction tolerates the presence of boryl, silyl, or bromine substituents on the aryl iodides. From a mechanistic point of view, the process involves syn-arylpalladation followed by syn-dehydropalladation.

Palladium-Catalyzed Cyclization/Alkenylation of Ynone Oximes with Vinylsilanes for the Assembly of Isoxazolyl Vinylsilanes

A palladium-catalyzed cascade cyclization/alkenylation for the assembly of synthetically valuable isoxazolyl vinylsilane derivative has been accomplished. Easily accessible ynone oximes, and available vinylsilane agents were used as the reaction starting materials This protocol features broad substrate scope, good functional group tolerance, and good step- and atom-economy. Remarkably, this approach provides a new approach for the construction of structurally diverse isoxazolyl-containing vinylsilanes with high molecular complexity, showing a promising application in synthetic and pharmaceutical chemistry.

Palladium-Catalyzed Regioselective C-H Functionalization/Annulation Reaction of Amides and Allylbenzenes for the Synthesis of Isoquinolinones and Pyridinones

A regioselective C-H functionalization/annulation reaction of N-sulfonyl amides and allylbenzenes through a palladium-catalyzed C(sp²)-H allylation/aminopalladation/β-H elimination/isomerization sequence has been reported. Various aryl and alkenyl carboxamides are found to be efficient substrates to construct isoquinolinones and pyridinones in up to 96% yield. Using ambient air as the terminal oxidant is another advantage regarding environmental friendliness and operational simplicity.

Combined Dynamic Kinetic Resolution and C-H Functionalization for Facile Synthesis of Non-Biaryl-Atropisomer-Type Axially Chiral Organosilanes

Although asymmetric C-H functionalization has been available for the synthesis of structurally diverse molecules, catalytic dynamic kinetic resolution (DKR) approaches to change racemic stereogenic axes remain synthetic challenges in this field. Here, a concise palladium-catalyzed DKR was combined with C-H functionalization involving olefination and alkynylation for the highly efficient synthesis of non-biaryl-atropisomer-type (NBA) axially chiral oragnosilanes. The chemistry proceeded through two different and distinct DKR: first, an atroposelective C-H olefination or alkynylation produced axially chiral vinylsilanes or alkynylsilanes as a new family of non-biaryl atropisomers (NBA), and second, the extension of this DKR strategy to twofold o,o'-C-H functionalization led to the multifunctional axially chiral organosilicon compounds with up to >99 % ee.

Recent development in transition metal-catalysed C-H olefination

Transition metal-catalysed functionalizations of inert C-H bonds to construct C-C bonds represent an ideal route in the synthesis of valuable organic molecules. Fine tuning of directing groups, catalysts and ligands has played a crucial role in selective C-H bond (sp2 or sp3) activation. Recent developments in these areas have assured a high level of regioselectivity in C-H olefination reactions. In this review, we have summarized the recent progress in the oxidative olefination of sp2 and sp3 C-H bonds with special emphasis on distal, atroposelective, non-directed sp2 and directed sp3 C-H olefination. The scope, limitation, and mechanism of various transition metal-catalysed olefination reactions have been described briefly.

Cu-Catalyzed highly selective silylation and borylation of alkenylsulfonium salts

A Cu-catalyzed highly selective silylation and borylation of alkenylsulfonium salts under mild conditions is reported providing various alkenylsilanes and alkenylboranes.