Brønsted Base-Catalyzed Tandem Isomerization-Michael Reactions of Alkynes: Synthesis of Oxacycles and Azacycles
作者:Hongjun Liu、Wei Feng、Choon Wee Kee、Dasheng Leow、Wei-Tian Loh、Choon-Hong Tan
DOI:10.1002/adsc.201000618
日期:2010.12.17
An efficient synthesis of oxacycles and azacycles was developed using a Brønsted base-catalyzed tandem alkyne isomerization–Michael reaction sequence. Functionalized 2-alkylidenetetrahydrofurans were prepared by an intramolecular oxy-Michael reaction on an allene that was generated in situ from an alkynoate. The aza-Michael version using alkynylamines, alkynylamides and alkynyl carbamates led to piperidines
利用布朗斯台德碱催化的串联炔烃异构化-迈克尔反应序列,开发了一种有效的氧杂环和氮杂环的合成方法。通过在链烯酸酯上原位产生的烯丙基上的分子内氧-迈克尔反应,制备官能化的2-亚烷基四氢呋喃。使用炔基胺,炔基酰胺和氨基甲酸酯的氮杂-迈克尔版本分别导致了哌啶,内酰胺和恶唑烷酮。该反应的对映选择性形式产生具有高对映选择性的轴向手性内酰胺。但是,某些炔烃无法完成分子内迈克尔反应,无法提供对映体富集的烯。