Síntese de selenetos de bis-vinila e bromoalquenos

Abstract

A simple and efficient protocol to prepare divinyl selenides has been developed by the regio- and stereoselective addition of sodium selenide species to aryl alkynes. The nucleophilic species was generates in situ, from the reaction of elemental selenium with NaBH 4 . Several divinyl selenides were obtained in moderate to excellent yields with selectivity for the (Z,Z)-isomer, these were carried out at 60 or 90 °C utilizing PEG-400 as the solvent. Further, we described a new method to the stereoselective hydrodebromination of 1,1-dibromoalkenes using a catalytic amount of the nucleophilic species of tellurium, generated in situ by the reaction of elemental tellurium with NaBH 4 . By this methodology, (E)-bromoalkenes were obtained in moderate to excellent yields. Furthermore, a high stereoselectivity for the (E)-isomer was observed when 1,1-dibromoarylalkenes were used, thus becoming a promising alternative for future applications in organic synthesis.