A Hg(ClO4)2·3H2O Catalyzed Sakurai–Hosomi Allylation of Isatins and Isatin Ketoimines Using Allyltrimethylsilane
摘要:
It is reported that Hg(ClO4)(2)center dot 3H(2)O could efficiently activate the cheap but less reactive allyltrimethylsilane for the allylation of isatins or isatin ketoimines, with catalyst loading down to 0.1 mol %. This is the first example of Sakurai-Hosomi allylation of ketoimines using allyltrimethylsilane. A rare example of chiral mercury catalysis is also reported.
Synthesis of 1′-aryl-2′-(2-oxoindolin-3-yl)spiro[indoline-3,5′-pyrroline]-2,3′-dione via one-pot reaction of arylamines, acetone, and isatins
作者:Yan Sun、Jing Sun、Chao-Guo Yan
DOI:10.1016/j.tetlet.2012.05.023
日期:2012.7
An efficient synthetic method for 1′-aryl-2′-(2-oxoindolin-3-yl)spiro[indoline-3,5′-pyrroline]-2,3′-diones was successfully developed via the one-pot domino reaction of arylamines, acetone, and isatins in acetic acid. The reaction mechanism involved the sequential Michael addition and ring closure of the in situ formed 3-N-aryliminoisatin and isatylidene acetone.
The direct α-cyanoamination of isatins using TMSCN has been developed, which is carried out in methanol without any catalyst. A new bifunctional cinchona alkaloid-based phosphinamide catalyst 7 could promote the Strecker reaction of isatins derived ketimine with TMSCN in up to 74% ee.
Rhodium-Catalyzed Asymmetric Formal Cycloadditions of Racemic Butadiene Monoxide with Imines
作者:Zhaoqun Liu、Xiangqing Feng、Haifeng Du
DOI:10.1021/ol301248d
日期:2012.6.15
sulfur−alkene hybrid ligand has proven to be highly effective for rhodium-catalyzed formal cycloaddition reactions of racemic butadiene monoxide and imines to furnish spirooxindole oxazolidines or 1,3-oxazolidines with high yields and stereoselectivities. A possible dynamickineticresolution as well as a kineticresolution is considered to be involved in this catalytic process.
An efficient and stereoselective reaction between 3-isothiocyanato oxindoles and isatins/isatinimines has been developed to afford structurally diverse dispiro[oxazolidine-2-thione]bisoxindoles and dispiro[imidazolidine-2-thione]bisoxindoles in excellent results under mild conditions. The potential of asymmetric induction by means of a chiral auxiliary was explored. The isomers are separable, and products could be isolated as single diastereomers by column chromatography. Further synthetic transformations of the reaction product were also successfully realized.
“On water” synthesis of spiro-indoles via Schiff bases
作者:Siva S. Panda、Subhash C. Jain
DOI:10.1007/s00706-011-0697-x
日期:2012.8
AbstractA fast, efficient, and clean “on water” synthesis of new Schiffbases and their conversion to spiro compounds undermicrowaveirradiation, as well as in water, is reported. Indol-2,3-diones were reacted separately with various heterocyclic and aromatic amines in water at room temperature to obtain corresponding Schiffbases in high purity and yield. These were then converted into corresponding