Palladium-catalyzed ortho-arylation of benzoic acid derivatives via C–H bond activation using an aminoacetic acid bidentate directing group

Palladium-Catalyzed Arylation of C(sp2)-H Bonds with 2-(1-Methylhydrazinyl)pyridine as the Bidentate Directing Group

Palladium-catalyzed C(sp²)-H arylation of ortho C-H bonds involving 2-(1-methylhydrazinyl)pyridine (MHP) as the directing group has been investigated. The reaction proceeds smoothly under an air atmosphere to generate biaryl derivatives in an environmentally friendly manner while tolerating a wide range of functional groups. Notably, the directing group present in the product could be easily removed under mild reductive conditions.

Structural Investigation and Molecular Modeling Studies of Strobilurin-Based Fungicides Active against the Rice Blast Pathogen Pyricularia oryzae

The increasing emergence of fungicide-resistant pathogens requires urgent solutions for crop disease management. Here, we describe a structural investigation of new fungicides obtained by combining strobilurin and succinate dehydrogenase inhibitor pharmacophores. We identified compounds endowed with very good activity against wild-type Pyricularia oryzae, combined in some cases with promising activity against strobilurin-resistant strains. The first three-dimensional model of P. oryzae cytochrome bc1 complex containing azoxystrobin as a ligand was developed. The model was validated with a set of commercially available strobilurins, and it well explains both the resistance mechanism to strobilurins mediated by the mutation G143A and the activity of metyltetraprole against strobilurin-resistant strains. The obtained results shed light on the key recognition determinants of strobilurin-like derivatives in the cytochrome bc1 active site and will guide the further rational design of new fungicides able to overcome resistance caused by G143A mutation in the rice blast pathogen.

Bidentate Directing Groups: An Efficient Tool in C-H Bond Functionalization Chemistry for the Expedient Construction of C-C Bonds

During the past decades, synthetic organic chemistry discovered that directing group assisted C-H activation is a key tool for the expedient and siteselective construction of C-C bonds. Among the various directing group strategies, bidentate directing groups are now recognized as one of the most efficient devices for the selective functionalization of certain positions due to fact that its metal center permits fine, tunable, and reversible coordination. The family of bidentate directing groups permit various types of assistance to be achieved, such as N,N-dentate, N,O-dentate, and N,S-dentate auxiliaries, which are categorized based on the coordination site. In this review, we broadly discuss various C-H bond functionalization reactions for the formation of C-C bonds with the aid of bidentate directing groups.

Ni(ii)-catalyzed mono-selective ortho-arylation of unactivated aryl C–H bonds utilizing amino acids as a directing group

The nickel(ii)-catalyzed ortho-arylation of unactivated C–H bonds utilizing amino acids as directing groups with aryl iodides or bromides as coupling electrophiles is described.

Visible-Light-Promoted C-H Arylation by Merging Palladium Catalysis with Organic Photoredox Catalysis

The use of a dual palladium/organic photoredox catalytic system enables the directed arylation of arenes with aryldiazonium salts with a broad substrate scope at room temperature under mild reaction conditions. This study thus serves as not only an alternative route for the biaryl motifs but also a new example for the application of an organic photoredox catalyst.

Sulfinyl isobutyramide as an auxiliary for palladium(ii)-catalyzed C–H arylation and iodination of benzylamine derivatives

An original readily available and versatile bidentate 2-methylsulfinyl isobutyramide directing group has been developed for benzylamine derivatives.

A Domino Oxidation/Arylation/Protodecarboxylation Reaction of Salicylaldehydes: Expanded Access to meta-Arylphenols

A method that allows salicylaldehydes to be efficiently transformed into meta-arylated phenol derivatives through a cascade oxidation/arylation/protodecarboxylation sequence is presented. We demonstrate that the aldehyde functional group can be used as a convenient removable directing group to control site selectivity in C-H activation. Aldehydes are easily introduced into the starting materials and the group is readily cleaved after the C-H functionalization event.

The mechanism of palladium(II)-mediated C–H cleavage with mono-N-protected amino acid (MPAA) ligands: origins of rate acceleration

It has long been known that transition metals are capable of interacting with, cleaving, and mediating the functionalization of activated and unactivated carbon–hydrogen (C–H) bonds. Broadly speaking, a basic underlying principle in the fields of inorganic and organometallic chemistry is that the primary and secondary coordination spheres around a metal affect its reactivity and selectivity in elementary reactions. Hence, ligand design in transition metal catalysis has been a captivating area of research for over half a century. The discovery and development of novel ligands to promote and control otherwise recalcitrant C–H functionalization reactions is now at the forefront of organic and organometallic chemistry. Central to this line of inquiry is the interplay between ligand, substrate, metal, and reaction mechanism. This Review highlights the mechanistic details of palladium(II)-mediated C–H cleavage with mono-N-protected amino acid (MPAA) ligands. Relevant historical background is discussed, the key discoveries in catalysis with MPAAs are examined, experimental and computational studies to elucidate reaction mechanisms are presented, and possible future directions are described.

Palladium-catalyzed direct C–H arylation of 3-aryl-2H-benzo[1,2,4]thiadiazine 1,1-dioxides: an efficient strategy to the synthesis of benzothiadiazine-1,1-dioxide derivatives

An efficient strategy to the synthesis of 3-aryl-2H-benzo[1,2,4]thiadiazine 1,1-dioxide derivatives via palladium-catalyzed direct arylation of benzothiadiazine-1,1-dioxides with various aryl iodides is described.

Reactivity of (poly)fluorobenzamides in palladium-catalysed direct arylations

Under PdCl₂/PivOK as reaction conditions, fluoro substituents act as better directing groups than amides in the palladium-catalysed direct arylations.