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Herein, we report a Pd(0)-catalyzed cascade reaction of intramolecular indolyl isocyanide-insertion, isocyanide-initiated scaffold-rearrangement with indolyl migration and redox-neutral process, which affords an efficient access to indolylisoindolinones. Isocyanide as a C (sp 3 ) H-N synthon and the alkyl motif of isocyanide as a hydride source have been explored for the first time.

A regioselective Ag(I)-promoted Pd-catalyzed C3-H activation-arylation of pyrido[1,2-a]pyrimidin-4-ones with bromo/iodo-(hetero)arenes under aqueous conditions has been developed. It affords an efficient access to pharmaceutically important versatile 3-aryl-pyrido[1,2-a]pyrimidin-4-ones. Interestingly, the arylation undergoes via a pathway with an unusual feature involving the formation of cationic arylpalladium species promoted by halo-sequestering Ag salts enabling concerted C3-palladation-deprotonation, as explored by relevant experiments and spectroscopic studies. The present approach is step economical, good yielding, and compatible with various functionalities and applicable to a wide range of starting materials.

A new and efficient approach for the synthesis of biologically important 2-aryl-4H-pyrido[1,2-a]pyrimidin-4-ones and 6-aryluracils via previously unknown Pd-catalyzed enolic C-OH activation-arylation of pyridopyrimidin-2,4-diones and barbituric acids, respectively, with boronic acids is reported. The starting materials are readily available, and products are obtained in high yields. An efficient and chemo- and stereoselective access to various tri- and tetrasubstituted conjugated alkenones and alkenoates is also obtained in this arylation approach. Interestingly, the procedure for the construction of such diverse molecular frameworks is general and featured with excellent substrates scope, tolerance of a broad range of functionalities, the unusual viability of performing the reaction under open air and in aqueous cosolvent, and the amenability to a scale-up synthesis, which have been found to be common limitations in the conventional/classical routes. The application of the protocol in a simple one-step high-yield route to pharmaceutically important polyarylated pyridopyrimidinone demonstrates its further synthetic utility.

Concerted metalation deprotonation (CMD) approach with appropriate proton shuttle precursor, base, and solvent (PivOH-K(2)CO(3)-toluene) has rendered a regioselective Pd-catalyzed C6-arylation of 3-aminoimidazo[1,2-a]pyrazine, a therapeutically relevant scaffold accessible by multicomponent reaction. The arylation of this heteroarene suffers from competing C5 and C2'-arylation reactions, while the developed process has virtually eliminated these competing arylations. Density functional calculations for CMD C-H activation at C6, C5, C8, and C2' sites imply that the energy barrier with distortion energy penalty as major contributing component influences the regioselectivity.

An efficient two-step approach, comprising the Friedel--Crafts reaction of 2-bromobenzoyl chlorides with indoles to give 3-(2-bromobenzoyl)indoles and their palladium-catalyzed intramolecular direct arylation to give indenoindolones, has been developed. 3-(2-Bromobenzoyl)indoles were crucial intermediates; the method was successful with N-unprotected or N-protected indoles. This approach affords a convenient preparation of diverse substituted and functionalized indenoindolones in good to high yields from easily accessible starting materials. Several moieties, which are commonly integrated into bioactive compounds, can be incorporated with ease by this synthesis. [ABSTRACT FROM AUTHOR]

Palladium acetate catalyzed Mizoroki–Heck reaction of arylboronic acids with phenyl vinyl sulfones afford α,β-unsaturated sulfones in good yields. [Copyright &y& Elsevier]

Focuses on the chemoselective hydrogenation of phosphonates and alpha,beta-unsaturated sulfones through palladium-assisted hydrogen transfer in connection with the ammonium formate. How the reduction of phosphonates is usually carried out; Filtration of catalysts involved.