125743-39-7Relevant articles and documents
Development, Scope, and Applications of Titanium(III)-Catalyzed Cyclizations to Aminated N-Heterocycles
Leijendekker, Leonardus H.,Weweler, Jens,Leuther, Tobias M.,Kratzert, Daniel,Streuff, Jan
supporting information, p. 3382 - 3390 (2019/02/14)
The exceptionally mild conditions of a titanium(III)-catalyzed cyclization reaction paired with a convenient acid/base extraction have enabled the straightforward synthesis, isolation, and direct N-functionalization of amino heterocycles such as 3-aminoindoles and -pyrroles. The unprotected heterocycles are ideal building blocks for the installation of aminated indoles and pyrroles into target molecules, but their sensitivity has previously impeded their synthesis by modern catalytic methods. This full paper presents the development and extended scope of the new cyclization methodology. The transformation of the products into fused bis-indoles is also demonstrated along with the discovery of an unusual palladium-catalyzed reductive biphenyl coupling reaction. The titanium(III)-catalyzed cyclization has also been applied to the synthesis of substituted 3-iminoindolines, which are of potential interest for applications in natural product synthesis and exhibit tunable blue-to-green fluorescence properties.
Catalytic Reductive Synthesis and Direct Derivatization of Unprotected Aminoindoles, Aminopyrroles, and Iminoindolines
Leijendekker, Leonardus H.,Weweler, Jens,Leuther, Tobias M.,Streuff, Jan
supporting information, p. 6103 - 6106 (2017/05/22)
A titanium(III)-catalyzed radical cyclization to unprotected 3-aminoindoles, 3-aminopyrroles, or 3-iminoindolines is reported. The reaction is non-hazardous, scalable, and allows facile isolation of the free products by extraction. The method is demonstrated on a large substrate scope and it further allows the direct installation of various nitrogen protecting groups or the synthesis of building blocks for peptide chemistry in a single sequence. Fused bisindoles can be directly accessed from the cyclization products.
Palladium(II)-catalyzed cyclization reaction of 2-(Alk-2'-ynyloxy) benzonitriles or 2-(Alk-2'-ynylamino)benzonitriles: A facile way to 2H-chromene and 1,2-dihydroquinoline derivatives
Xi, Guoqin,Han, Xiuling,Lu, Xiyan
supporting information, p. 2701 - 2705,5 (2012/12/12)
An efficient synthesis of 2H-chromenes and 1,2-dihydroquinolines from palladium(II)-catalyzed tandem reactions of 2-(alk-2'-ynyloxy)benzonitriles or 2-(alk-2'-ynylamino)benzonitriles was developed. This tandem reaction involves an intermolecular trans-acetoxypalladation of an alkyne followed by an addition to the nitrile group to quench the carbon-palladium bond and complete the catalytic cycle without the necessity of a redox system.
