通过铜催化的α-氧杂环丁烯N的氧化[3 + 2]环化反应,对苯并[ e ]吲哚-4,5-二酮和萘[2,1- b ]噻吩-4,5-二酮进行化学选择一锅法。 S-乙缩醛/β-酮硫代酰胺与α-/β-萘酚
摘要:
一种操作简单有效的一锅法,用于合成1-芳酰基(或烷酰基)-2-硫烷基-3-芳基(或烷基)-3 H-苯并[ e ]吲哚-4,5-二酮和萘并[首次在露天条件下通过铜催化的α-氧杂环丁烯N,S-乙缩醛/β-酮硫酰胺与α-/β-萘酚的交叉偶联反应设计了2,1- b ]噻吩-4,5-二酮。。该转化成功的关键是室温下将α-/β-萘酚氧化为1,2-萘醌作为反应性物质,然后通过α-氧杂环丁烯N,S进行正式的[3 + 2]环化反应-缩醛/β-酮硫酰胺通过迈克尔加成/互变异构化/氧化/环化/芳香化反应的级联序列,使得能够将吡咯/噻吩环加到萘醌部分上。此外,在无溶剂条件下将苯并[ e ]吲哚-4,5-二酮转化为五环稠合的吩嗪衍生物。根据我们的实验结果,提出了该化学选择性方案的初步机理论据,该方案得到了对照实验的充分验证和支持。
In(OTf)<sub>3</sub>-catalysed one-pot versatile pyrrole synthesis through domino annulation of α-oxoketene-N,S-acetals with nitroolefins
作者:Abhijeet Srivastava、Gaurav Shukla、Anugula Nagaraju、Girijesh Kumar Verma、Keshav Raghuvanshi、Raymond C. F. Jones、Maya Shankar Singh
DOI:10.1039/c4ob00781f
日期:——
In(OTf)3-catalyzed robust and sustainable one-pot access to previously unknown and synthetically demanding polysubstituted pyrroles via [3 + 2] annulation of α-oxoketene-N,S-acetals with β-nitrostyrenes has been achieved under solvent-free conditions. The merit of this domino Michael addition/cyclization sequence is highlighted by its operational simplicity, short reaction time (5–10 min), good to
An expeditious FeCl<sub>3</sub>-catalyzed cascade 1,4-conjugate addition/annulation/1,5-H shift sequence for modular access of all-pyrano-moiety-substituted chromenes
An operationally simple protocol is described for the facile, modular and regioselective access of all-pyrano-moiety-substituted iminochromenes, particularly under undried acetonitrile and air atmosphere.