Squaramide-catalysed asymmetric cascade reactions of 2,3-dioxopyrrolidines with 3-chlorooxindoles
作者:Jiang-Bo Wen、Da-Ming Du
DOI:10.1039/c9ob02663k
日期:——
A highly efficient method for the enantioselective construction of dispirocyclic compounds has been developed by the squaramide-catalysed asymmetricMichaeladdition/cyclizationcascadereaction of 2,3-dioxopyrrolidines with 3-chlorooxindoles. The corresponding chiral dispiro[indoline-3,1'-cyclopropane-2',3''-pyrrolidine]-2,4'',5''-triones were obtained in high yields with excellent stereoselectivities
Asymmetric synthesis of spirooxindole-fused spirothiazolones<i>via</i>squaramide-catalysed reaction of 3-chlorooxindoles with 5-alkenyl thiazolones
作者:Yong-Xing Song、Da-Ming Du
DOI:10.1039/c9ob00998a
日期:——
An efficient and practical organocatalyzed asymmetric formal [2 + 1] cycloaddition of 3-chlorooxindoles with 5-alkenyl thiazolones by using hydroquinine-derived squaramide as the catalyst has been developed. Under mild conditions, a broad range of spirooxindole-fused spirothiazolones bearing three adjacent stereogenic centers including two vicinal spiro quaternary chiral centers were obtained in high
An unusual rearrangement of saccharin-derived cyclic ketimines (SDCIs) and 3-chlorooxindoles has been developed to provide a series of spiro-1,3-benzothiazine oxindoles. The reaction features simple manipulations, short reaction times, mild reaction conditions and inexpensive reagents. It is the first example where SDCIs serve as a ring-opening reagent in organic synthesis.
Controllable transformation of indoles using iodine(<scp>iii</scp>) reagent
作者:Yinxiang Jian、Peng Liang、Xiaoyan Li、Huawu Shao、Xiaofeng Ma
DOI:10.1039/d2ob01951e
日期:——
combination of phenyliodinebis(trifluoroacetate) (PIFA) with n-Bu4NCl·H2O (TBAC) was exploited. Through controlling the amount of PIFA and TBAC from one to three equivalents, 3-chloro-indoles, 3-chloro-2-oxindoles, and 3,3-dichloro-2-oxindoles were obtained, respectively, in satisfactory to excellent yields. The advantages of the protocol include mild conditions, facile process with short reaction time, high