NaBH4/[bmim]BF4: a new reducing system to access vinyl selenides and tellurides

Abstract

Um método simples e geral foi desenvolvido para a síntese de selenetos e teluretos vinílicos a partir de alquinos terminais e dicalcogenetos de diorganoíla usando NaBH 4 e [bmim]BF 4 como solvente reciclável. Este método eficiente permite a formação preferencial de calcogenetos vinílicos de configuração Z na maioria dos exemplos estudados. Também foi observado que na reação envolvendo fenilacetileno, (E)-bis-fenilcalcogenoestirenos foram obtidos com bons rendimentos e alta seletividade. O líquido iônico foi reutilizado três vezes sem perda da eficiência.A general and simple method for the synthesis of vinyl selenides and tellurides starting from terminal alkynes and diorganyl chalcogenides using NaBH 4 and [bmim]BF 4 as a recyclable solvent was developed. This efficient and improved method furnishes the corresponding vinyl chalcogenides preferentially with Z configuration. We also observed that when the same protocol was applied to phenyl acetylene, (E)-bis-phenylchalcogeno styrenes were obtained in good yields and high selectivity. The ionic liquid was reused up three times without lost of efficiency.

Synthesis of Organochalcogen Compounds using Non-Conventional Reaction Media

“…For instance, ( Z )‐phenyl(styryl)tellane was obtained selectively in 83 % yield after 1.5 h. The PEG‐400 was reused for successive reactions using phenylacetylene and diphenyl diselenide as starting materials; after four runs using the same solvent, the product was obtained in comparable yields (85‐71 %). In the same work, we studied the reaction of diphenyl diselenide with phenylacetylene using glycerol as the solvent and a mixture of ( E )‐ and ( Z )‐1,2‐bis‐phenylseleno styrenes was formed, i. e., the reaction behavior in glycerol was similar to that using IL or without solvent …”

A mild and efficient procedure for alkenols oxyselenocyclization by using ionic liquids

“…Potewar et al described the condensation of selenourea with different phenacyl bromides employing mixtures of different alkylimidazolium ILs with water . Different groups prepared diorganyl selenides and selenolesters in a series of dialkylimidazolium ILs employing different promoters and catalysts as Zn dust, ZnO nanopowder, CuO nanopowder, NaBF 4 , Indium and InI, triphenyl phosphine, palladium, or the bimetallic reagent Sn(II)/Cu(II) . The use of [bmim][BF 4 ] and [bmim][PF 6 ] in the synthesis of diaryl selenides by electrophilic substitution in arylboron reagents with phenylselenyl halides has been also described .…”

Microwave-assisted synthesis of indole-2-carboxylic acid esters in ionic liquid

“…Since the start of this century an ever-growing number of studies has been published describing the use of ionic liquids. [12][13][14][15][16][17] Microwave-assisted organic synthesis has shown to be a valuable tool for reducing reaction times, getting cleaner reactions, improving yields, simplifying workup and designing energy-saving protocols. 18,19 Due to their ionic nature, ionic liquids allow highly effective interactions with microwave energy for the rapid generation of products with generally high yields.…”