MRV

Ni-catalyzed decarboxylative C(sp³)−N cross-coupling of redox active ester and oxime esters was realized through electrochemical cathodic reduction. Mechanistic studies unveil a high-valent nickel species-driven reductive elimination pathway, rather than direct radical-radical coupling. The utility of this methodology was demonstrated through a broad scope (1°, 2°, 3° carboxylic acids) and late-stage functionalization of complex molecules.

Abstract

A new electrochemical transformation is presented that enables chemists to couple simple alkyl carboxylic acid derivatives with an electrophilic amine reagent to construct C(sp³)−N bond. The success of this reaction hinges on the merging of cooperative electrochemical reduction with nickel catalysis. The chemistry exhibits a high degree of practicality, showcasing its wide applicability with 1°, 2°, 3° carboxylic acids and remarkable compatibility with diverse functional groups, even in the realm of late-stage functionalization. Furthermore, extensive mechanistic studies have unveiled the engagement of alkyl radicals and iminyl radicals; and elucidated the multifaceted roles played by ⁱ Pr₂O, Ni catalyst, and electricity.

Utilizing readily available and cost-effective aryl halides, amines, and butadienes as starting materials, in conjunction with rac-BINAP and a Pd catalyst, we can efficiently synthesize highly valuable complex allylamines through a rapid one-step process enabled by photocatalysis.

Abstract

A visible-light-induced, three-component palladium-catalyzed 1,4-aminoarylation of butadienes with readily available aryl halides and aliphatic amines has been developed, affording allylamines with excellent E-selectivity. The reaction exhibits exceptional control over chemo-, regio-, and stereoselectivity, a broad substrate scope, and high functional group compatibility, as demonstrated by the late-stage functionalization of bioactive molecules. Mechanistic investigations are consistent with a photoinduced radical Pd(0)-Pd(I)-Pd(II)-Pd(0) Heck-Tsuji–Trost allylation cascade.

Synlett
DOI: 10.1055/a-2225-8858

We report the photocatalytic functionalization of terminal alkenes to vicinal dichlorides by using visible light and FeCl3 as a catalyst, LiCl as a chloride source, and air as an oxidant. The transformation is proposed to be initiated by ligand-to-metal charge-transfer bond homolysis of a Fe–Cl bond, giving a highly reactive chloride radical able to initiate the functionalization of olefins. The process shows high chemoselectivity and broad functional-group tolerance with yields of up to 94% under mild conditions.
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Georg Thieme Verlag KG Rüdigerstraße 14, 70469 Stuttgart, Germany

Article in Thieme eJournals:
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Shaping Chirality from Heterocyles. The mild, organocatalytic generation of elusive ortho-quinodimethane intermediates (Het-oQDMs) from suitable heteroaromatic carbonyl- or carbonyl-like pronucleophiles has recently proved to be succesful in the development of enantioselective [4+2] cycloadditions, giving access to novel, chiral heterocyclic chemotypes featuring in-cycle stereocenters. This review provides a critical analysis of the most important advances in the field achieved in the last decade.

Abstract

Polycyclic compounds bearing a complex heterocyclic core such as an aromatic heterocycle “fused” with one or more functionalized rings, are widespread leading molecules in the domain of synthetic organic chemistry and pharmaceuticals. Although many synthetic methodologies have been devised to access achiral, fused heteroaromatic scaffolds, or related chiral variants adorned with out-of-cycle stereogenic elements, equally efficient strategies to afford chiral heterocycles featuring in-cycle stereocenters, exist to a lesser extent and presently represent a growing field of investigation. The mild, organocatalytic generation of elusive ortho-quinodimethane intermediates (oQDMs), derived from suitable heteroaromatic carbonyl- or carbonyl-like pronucleophiles has recently proved successful in the synthesis of such peculiar chiral architectures via stereoselective [4+2] cycloadditions. This review provides an overview of the most important advances attained in this field over the last decade.

This review explores methods for optimizing emission wavelength, quantum yield and photostability of traditional and newer non-planar fluorophores (squaraine-rotaxanes and cycloparaphenylenes). We focus on the fundamental physical organic chemistry concepts leading to the fluorescent properties. We provide a detailed tutorial to understand fluorescence and enable the design of superior fluorophores for chemical biology.Social media promotion:

Abstract

Labeling and detection of biomolecules in vitro and in vivo is essential to many areas of biomedical science. Fluorophores stand as indispensable tools within chemical biology, underscoring the importance of fine-tuning their optical properties. This review focuses on methods for optimizing emission wavelength, quantum yield and photostability. We focus not just on the trends, but the fundamental physical organic chemistry concepts that inform the connection between molecular structure and fluorescent properties. This approach offers an essential understanding of fluorescence, enabling readers to develop a systematic analytical framework for thinking about fluorescence. Furthermore, an evaluation of newer non-planar fluorophores shines light on the bright future of fluorescent molecules.

An asymmetric nickel/metallaphotoredox catalyzed C(sp³)−H benzylic carbamoylation employing alkylarenes and isocyanates is described. A broad array of 2-arylamides can be prepared in one pot under mild reaction conditions. Mechanistic studies, including control experiments and DFT calculations, shed light on the rate and stereodetermining step of this transformation.

Abstract

Radical-mediated Hydrogen Atom Abstraction of Csp³−H bonds has become a powerful tool for the asymmetric functionalization of organic feedstocks. Here, we present an asymmetric synthesis of α-aryl amides via carbamoylation of alkylarenes with isocyanates as electrophiles. The synergistic combination of a photoredox and a chiral nickel-catalyst, enables the use of readily available and neutral reagents under mild reaction conditions and provides straightforward access to pharmacologically relevant motifs in enantiomerically pure form.