Síntese de calcogenetos vinílicos utilizando solvente verdes

Abstract

In this work were developed three methodologies for the synthesis of vinyl chalcogen. The first methodology developed, was the synthesis of vinyl sulfides and tellurides from cross-coupling reaction of vinyl bromides of configuration E and Z with diaryl dichalcogenides using the catalytic system composed of copper iodide, zinc and glycerol as alternative solvent. Several vinyl chalcogenides were prepared stereoselectively and in good yields, and is still possible to reuse the catalytic system and solvent for five cycles without loss of activity (Scheme 1). The second methodology developed was the addition reaction the alkynes using diaryl dichalcogenides in the presence of CuI/Zn/glycerol, leading preferably to the formation of 1.2-bis-chalcogen alkenes of configuration E in 55-95% yields and in short reactional times. Through this method were synthesized unpublished compounds of type mono-and bis-chalcogen pyrazoles in good yields and in short periods of reaction (Scheme 2). The catalytic system was reused for five times after successive cycles without loss of activity. The third methodology developed was also based on the principles of green chemistry, using DES (Deep Eutectic Solvent) as alternative solvent for the synthesis of vinyl chalcogenides. The methodology is general and has been applied to a series of alkynes with electron donating group and electron-withdrawing on the aromatic ring, 1.4-diphenylbutadiine and alkyl and aryl dichalcogenides.