Photoinduced Electron Transfer Chemistry: Mechanism and Aplications in Organochalcogenide Synthesis.

ALICIA B. PEÑÉÑORY

Mendoza

Congreso; 21st I-APS; 2011

I-APS

Conferencia Invitada en el 21st Inter-American Photochemical Society Conference (21st I-APS) Photoinduced electron transfer (PET) reactions have become a useful tool in organic synthesis since difficult or unattainable transformations with more conventional organic reactions can be easily performed. In the first step of such a reaction, a radical ion pair is generated showing typical reactivities. Frequently, bond breaking leading to proton exchange or elimination of an ion subsequently affords neutral radicals. In the context of radical chemistry, these reactions are particularly valuable since they offer an easy access to radical species without using toxic reagents such as tin derivatives. At present, the use of radical reactions for the synthesis of target organic compounds is widely recognized and many studies describe the synthetic applications of different radical procedures. Among them, the radical nucleophilic substitution by the SRN1 mechanism has proven to be a versatile procedure to form new Carbon-Carbon and Carbon-heteroatom bonds. In addition, cyclization reactions of radicals leading to carbocyclic and heterocyclic compounds have been successfully applied to the synthesis of natural products. We have studied oxidative or reductive photoinduced electron transfer process to render primarily radical cations or radical anions, respectively, involving chalcogenide species and their reactivities. In the present communication, the synthesis of different aryl alkyl and diaryl sulphides, aryl methyl selenides, benzothiazoles, etc. will be discussed emphasizing the mechanism and the reactive intermediates involved.