2406-00-0Relevant academic research and scientific papers
Oxidative nitrene transfer from azides to alkynes via Ti(ii)/Ti(iv) redox catalysis: Formal [2+2+1] synthesis of pyrroles
Pearce, Adam J.,See, Xin Yi,Tonks, Ian A.
supporting information, p. 6891 - 6894 (2018/06/26)
Catalytic oxidative nitrene transfer from azides with the early transition metals is rare, and has not been observed without the support of redox noninnocent spectator ligands. Here, we report the formal [2+2+1] coupling of azides and alkynes via TiII/TiIV redox catalysis from simple Ti halide imido precatalysts. These reactions yield polysubstituted N-alkyl pyrroles, including N-benzyl protected pyrroles and rare examples of very electron rich pentaalkyl pyrroles. Mechanistic analysis reveals that [2+2+1] reactions with bulky azides have different mechanistic features from previously-reported reactions using azobenzene as a nitrene source.
Copper-mediated reaction of zirconacyclopentadienes with azides: A one-pot three-component synthesis of multiply substituted pyrroles from one azide and two alkynes
Zhou, Yiqing,Yan, Xiaoyu,Chen, Chao,Xi, Chanjuan
, p. 6182 - 6185 (2013/12/04)
A general method for the synthesis of multiply substituted pyrroles through zirconocene-mediated coupling of two alkynes and an azide in the presence of CuCl has been achieved.
Palladium-catalyzed reaction of arylamine and diarylacetylene: Solvent-controlled construction of 2,3-diarylindoles and pentaarylpyrroles
Chen, Xiaopeng,Li, Xihui,Wang, Ningning,Jin, Jisong,Lu, Ping,Wang, Yanguang
experimental part, p. 4380 - 4386 (2012/09/21)
By choosing DMF and dioxane as solvent, skeletons of indoles and pyrroles were constructed from alkynes and amines in the presence of PdCl2, respectively. These Pd-catalyzed reactions were phosphane-free with high atom efficiency and could be conducted under mild basic conditions. The proposed mechanism for the selective formation of indoles and pyrroles in different solvents is also discussed in this paper. Two different kinds of Pd-catalyzed cyclizations, leading to the construction of 2,3-diarylindole and pentaarylpyrrole from the same alkyne and aniline starting materials, were approached by choosing different solvents. The mechanisms for these solvent-controlled reactions are proposed and discussed. Copyright
Copper-catalyzed double N-vinylation of aromatic amines: An efficient synthesis of various substituted N-arylpyrroies
Liao, Qian,Zhang, Liyun,Wang, Fei,Li, Shutao,Xi, Chanjuan
experimental part, p. 5426 - 5431 (2010/11/18)
A simple and efficient approach to various substituted N-arylpyrroles has been developed. The method is based on the copper-catalyzed sequential inter- and intramolecular Nvinylation of aromatic amines. The reactions proceed to afford substituted N-arylpyrroles in good-to-excellent yields using CuI as the precatalyst, iBuONa as the base, and N1,N2dimethylethane- l,2-diamine (DMEDA) as the ligand. Ani-lines with electron-donating and -withdrawing substituents as well as a heteroaromatic amine performed very well under the conditions used. Tri- and tetrasubstituted dienyl diiodides also performed well under the reaction conditions and afforded the corresponding substituted N-arylpyrroles in good yields, Products were also obtained in high yields with CuBr or CuCl as precatalyst.
FERRICYANIDE OXIDATION OF 1-SUBSTITUTED PENTAPHENYLPYRIDINIUM SALTS. A NOVEL ROUTE TO 1-SUBSTITUTED 2,3,4,5-TETRAPHENYLPYRROLES
Boehm, Stanislav,Slavik, Hanus,Kuthan, Josef
, p. 200 - 205 (2007/10/02)
Oxidation of 1-substituted 2,3,4,5,6-pentaphenylpyridinium salts Ia-Ij by potassium ferricyanide in an alkaline medium yields the corresponding 1-substituted 2,3,4,5-tetraphenylpyrroles in 68 to 76percent yields.The selectivity of the reaction is discusse
