Synthesis of disulfides tethered pyrroles from β-ketothioamides via a bicyclization/ring-opening/oxidative coupling reaction
作者:Cong-Xiang Li、Rui-Juan Liu、Kun Yin、Li-Rong Wen、Ming Li
DOI:10.1039/c7ob00655a
日期:——
A DABCO-promoted three-component reaction of β-ketothioamides (KTAs), arylglyoxals and 2-cyanoacetates to access disulfides tethered pyrroles by air as oxidant has been disclosed. Importantly, this protocolinvolves a tandem sequence that includes Knoevenagel condensation, Michaeladdition, N-cyclization, O-cyclization, ring-opening and oxidative coupling.
Herein, we unveiled the novel approach for the synthesis of α-oxoketene S,S- and N,S-acetals employing a Mitsunobuprotocol. A wide range of alcohols has been successfully utilized, enabling great tolerability to this reaction. A diverse set of β-keto(dithioesters/thioamides) bearing various functional groups were found to be well suited substrates for this reaction, showing no obvious electronic effect
Rhodium(II)-Catalyzed Annulative Coupling of β-Ketothioamides with α-Diazo Compounds: Access to Highly Functionalized Thiazolidin-4-ones and Thiazolines
An operationally simple and efficient one-pot protocol for the synthesis of highly functionalized thiazolidin-4-ones and thiazolines has been devised via Rh(OAc)2-catalyzed annulative coupling of β-ketothioamides with diazo compounds under mild reaction conditions for the first time. This double functionalization of diazo compounds proceeds via selective S-alkylation followed by intramolecular N-cyclization
Acid-promoted rapid solvent-free access to substituted 1,4-dihydropyridines from β-ketothioamides
作者:Ming Li、Ke-Na Sun、Li-Rong Wen
DOI:10.1039/c5ra26931h
日期:——
β-Ketothioamides (KTAs) have been used as building blocks with aldehydes and β-enaminonitriles for synthesis of 1,4-dihydropyridines in the presence of AcOH under solvent-free conditions within 5 min. This new strategy exhibits remarkable features such as high chemoselectivity, mild reaction conditions, easily available substrates, and good yields.
Chemoselective one-pot access to benzo[e]indole-4,5-diones and naphtho[2,1-b]thiophene-4,5-diones via copper-catalyzed oxidative [3 + 2] annulation of α-oxoketene N,S-acetals/β-ketothioamides with α-/β-naphthols
作者:Dhananjay Yadav、Gaurav Shukla、Monish A. Ansari、Abhijeet Srivastava、Maya Shankar Singh
DOI:10.1016/j.tet.2018.08.026
日期:2018.10
An operationally simple and efficient one-pot method for the synthesis of 1-aroyl (or alkanoyl)-2-thioalkyl-3-aryl (or alkyl)-3H-benzo[e]indole-4,5-diones and naphtho[2,1-b]thiophene-4,5-diones has been devised by copper-catalyzed cross-coupling of α-oxoketene N,S-acetals/β-ketothioamides with α-/β-naphthols in open air for the first time. The key to the success of this transformation is the room temperature
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。