Síntese estereosseletiva de bis- e tris-calcogenetos vinílicos mistos

• Ano de defesa: 2007
• Autor(a) principal: Schneid, Caroline Cassalha Schneider
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Federal de Santa Maria; Brasil; Química; UFSM; Programa de Pós-Graduação em Química; Centro de Ciências Naturais e Exatas
• Palavras-chave em Português: Síntese estereosseletiva; CNPQ::CIENCIAS EXATAS E DA TERRA::QUIMICA
• Link de acesso: http://repositorio.ufsm.br/handle/1/23851

In the work presented herein we describe the reaction of diorganoyl dichalcogenides with terminal alkynes under catalyst free conditions, by one pot procedure, to prepare unsymmetrical bis- and tris-chalcogenide alkenes selectively, avoiding the previous preparation of chalcogenealkynes. The reaction proceeded cleanly under mild reaction conditions and the addition of dichalcogenides to alkynes occurred stereoselectively to give exclusively the corresponding Z isomers. The selectivity control of reaction was governed by the effective participation of the hydroxyl group from propargyl alcohols. Indeed, unsymmetrical bis-chalcogenide alkenes were obtained with propargyl alcohol having the acidic hydroxyl group hydrogen. On the other hand, unsymmetrical tris-chalcogenide alkenes were exclusively obtained from alkynes with no potentially acidic hydroxyl group hydrogen.