Methods of biological samples field analysis

With the financial support of Internal Security Fund Police Programme European Commission Directorate General Home Affairs. This project has been founded with support from the European Commission. This publication reflects the views only of the authors, and European Commission cannot be held responsible for any use which may be made of the information contained therein

Pyridine N-oxides as HAT reagents for photochemical C-H functionalization of electron-deficient heteroarenes

Pyridine N-oxides only recenly marked their presence in the photocatalysis outbreak, mainly serving as oxypyridinium salt precursors. Herein, their unique reactivity as a hydrogen atom transfer reagent in photochemical, Minisci-type alkylation of electron-deficient heteroarenes is unveiled. The formation of an EDA complex between a heterocyclic substrate and N-oxide precludes the need for a photocatalyst. The developed method allows for a broad range of radical precursors to be used, namely alkanes, alkenes, amides, and ethers, for efficient alkylation of azines

From Amines to Alkynes – Lighting the Way

We present a metal-free photoredox strategy for the formation of Csp3-Csp bonds from redox-activated primary amine derivatives. The developed reaction of 2,4,6-triphenylpyridiniu salts with alkynyl tosylates, leading to functionalized alkynes , is easily scalable, offers broad substrate scope, high chemoselectivity, and mild conditions. Its potentials also highlighted by diversification of complex molecular scaffolds. Moreover, mechanistic studies contribute to the elucidation of unexpected differences in reactivity of primary, secondary and alkyl pyridinium salts

Photocatalytic Alkylation of Pyrroles and Indoles with α-Diazo Esters

This article describes direct photoalkylation of electron-rich aromatic compounds with diazo compoiunds. C-2 alkylated indoles and pyrroles are obtained with good yields even though the photocatalyst (Ru(bpy)3Cl2) loading is as low as 0.075 mol %. For substrates bearing electron-withdrawing substituents the addition of a catalytic amount of N,N-dimethyl-4-methoxyaniline is required. Both EWG-EWG and EWG-EDG substituted diazo esters are suitable as alkylating agents. The reaction selectivity and mechanistic experiments suggest that carbenes/carbenoid intermediates are not involved in the reaction pathway, instead radical formation is proposed

Prolinethioamides versus Prolinamides in Organocatalyzed Aldol Reactions—A Comparative Study

Various organocatalysts have been developed for the aldol reaction but particular attention has been paid to prolinamide derivatives. They are easy to prepare and their catalytic activity can be readily tuned through structural modification. In this review, the comparison of catalytic activities between prolinethioamides and their respective amides in direct asymmetric aldol reactions is presented

Porphyrin-catalyzed photochemical C-H arylation of heteroarenes

Organic dyes are a promising class of photoredox catalysts and offer a meaningful alternative to broadly applied Ru and Ir complexes. We found that porphyrins with tuned physicochemical properties, by tailoring various substituents at the periphery of the macrocycle, are effective in catalyzing the light-induced direct arylation of heteroarenes and coumarins with diazonium salts. Mechanistic studies confirmed that the reaction operates by an oxidative quenching pathway of the porphyrin