Síntese de 3-organocalcogenil-2-organo-cromenonas via reações de ciclização intramolecular mediada por selectfluor®

Abstract

This paper reports the development of an effective synthetic protocol between 1,3- organo-propynones 1 and different diorganoyl dicalcogenides 2 mediated by Selectfluor® and employing acetonitrile as a solvent, at room temperature and open atmosphere for a time of 20 h to obtain a series of 2-organo-3-organoselenyl-chromen-4-ones 3. Through the developed methodology, it was possible to synthesize different chromenones (21 compounds) with yields ranging from 27% to 89%, which 8 of these are unpublished examples. The method is also suitable for the formation of several classes of heterocycles such as thiochromenone and isochromenone. The proposed mechanism for the reaction is based on the cleavage of diorganoyl dichalcogenide promoted by Selectfluor®, which generates electrophilic chalcogenium species capable to activate the triple bond of propynone to promote the intramolecular cyclization.