Síntese de selanil-(hetero)arenos e 3-selanil-4-amino-2H-cromen-2-onas via selenilação promovida por Selectfluor®

Abstract

In the present work, two synthetic methodologies were developed to access organochalcogen compounds, from direct selenylation reactions using several (hetero)arenes or 4-amino-2H-chromen-2-ones and diorganyl diselenides as selenium source. In both protocols, a safe, stable, non-toxic and non-hygroscopic oxidizing agent marketed as Selectfluor® was used. From data obtained by our research group, it was observed that the oxidizing agent promotes the cleavage of the selenium-selenium bond in diorganyl diselenides to form active electrophilic selenium species. In the first work of this thesis, the synthesis of 15 compounds derived from selanyl-(hetero)arenes, obtained in reaction yields ranging from 21% to 98%, is reported. In the second work of this thesis, the synthesis of 20 compounds derived from 3-selanyl-4-amino-2H-chromen-2-ones is reported, obtained in reaction yields ranging from 31% to 97%, using the preparation as methodology of the nucleophilic species in the presence of NaHCO3 in dimethylformamide separately from the electrophilic species, prepared in the presence of the selenium source and Selectfluor® in acetonitrile. After fifteen minutes, the solution containing the electrophilic species is slowly added onto the solution containing the nucleophilic species, which remains for 24 hours under stirring at room temperature. An oxidation reaction was also tested using one of the selenylation products to form 8-methyl-4-(phenylamino)-3-(phenylseleninyl)chromen-2-one. The 36 compounds synthesized in this thesis were characterized and identified by nuclear magnetic resonance spectroscopy of hydrogen (¹H), carbon (¹³C), selenium (77Se) and in some cases fluorine (¹9F), as well as by high resolution mass spectroscopy (HRMS), melting point and by single crystal X-ray diffraction. The two reported methodologies promote easy access to organoselenium compounds under mild conditions with moderate to excellent reaction yields without the need for an inert atmosphere system.