Fast electron transfer C-alkylation of 2-nitropropane anion under microwave irradiation

An expedient route to heterocycles through α-arylation of ketones and arylamides by microwave induced thermal SRN1 reactions

Quick reaction by microwave irradiation promotes nucleophilic substitution by thermally induced electron transfer mechanism and allows to synthesize deoxibenzoin and indol heterocycles derivates by inter or intramolecular ring closure.

Synthesis of alpha,beta-unsaturated ketones as chalcone analogues via a S(RN)1 mechanism

An electron-transfer chain reaction between 2-nitropropane anion and alpha-bromoketones derived from nitrobenzene and nitrothiophene was demonstrated by mechanistic study and a specific convenient synthetic protocol. Thus, 2-bromo-1-(5-nitrothiophen-2-yl)ethanone or 2-bromo-1-(4-nitrophenyl)ethanone were reacted with several cyclic nitronate anions to form alpha,beta-unsaturated ketones via a S(RN)1 mechanism. This new method can be used to synthesize a wide variety of chalcone analogues.

Les réactions de transfert monoélectronique : de l’électron au médicament

Electron transfer reactions have been at the heart of great advances in organic and inorganic chemistry and biology since the early work in 1954 by H. Taube (Nobel Chemistry Prize in 1983) and R. Marcus (Nobel Chemistry Prize in 1991). In organic chemistry, a new kind of chain substitution reaction with paramagnetic species was defined and identified as S(RN)1 (substitution, radial-nucleophilic, unimolecular). In our laboratory, choosing more or less complex molecules which possess electron-withdrawing groups and correctly disposed alkylation sites has enabled us to extend this concept to the heterocyclic (S(RN)1 HET) and quinonic (S(RN)1 QUI) series. These studies led us to prepare, under mild operating conditions, highly branched molecules hard to obtain via other pathways and which possess high pharmacological activity in various fields. We have discovered new reaction mechanisms such as LD-S(RN)1 (long-distance S(RN)1) E(RC)1 (elimination radical chain, unimolecular), bis-S(RN)1 and poly-S(RN)1. Moreover, we have developed a new technology using microwaves which increases the interest of electron transfer reactions in medicinal chemistry for drugs synthesis.