Neutral Ti Complexes as Catalysts for the Hydroamination of Alkynes and Alkenes: Do the Labile Ligands Change the Catalytic Activity?
作者:Kerstin Gräbe、Frauke Pohlki、Sven Doye
DOI:10.1002/ejoc.200800471
日期:2008.10
A detailed comparison between three four-coordinate Ti complexes featuring the general bidentate ligand [η5-(C5H4)-SiMe2-NtBu]2– and two ligands X (NMe2, Me, Cl) as catalyst precursors (I–III) for the intermolecularhydroamination of alkynes and the intramolecular hydroamination of alkenes is presented. The results strongly suggest that the catalytically active species are only identical for reactions
三个四配位 Ti 配合物的详细比较,这些配合物具有一般双齿配体 [η5-(C5H4)-SiMe2-NtBu]2- 和两个配体 X(NMe2、Me、Cl)作为分子间催化剂前体(I-III)介绍了炔烃的加氢胺化和烯烃的分子内加氢胺化。结果强烈表明催化活性物质仅对于用双(二甲基酰胺基)配合物 I 或二甲基配合物 II 进行的反应是相同的。在反应条件下,不稳定的配体X通过反应胺被蛋白水解除去,与二甲胺或甲烷一起形成具有催化活性的亚氨基或酰氨基复合物。尽管两种催化剂前体均可成功用于多种底物组合,但制备和动力学研究清楚地表明,二甲胺、由双(二甲基酰胺基)催化剂前体 I 和反应胺形成的化合物能够将具有催化活性的酰亚胺基或酰胺基配合物转化回催化剂前体,从而抑制反应。因此,双(二甲基酰胺基)催化剂前体 I 的催化性能比相应的二甲基配合物 II 差。此外,表明二氯配合物 III 只是用于选定的加氢胺化反应的合
Selective mono- and di-N-alkylation of aromatic amines with alcohols and acylation of aromatic amines using Ph3P/DDQ
Selective N-monoalkylation of aromatic amines with 1° and 2° alcohols and conversion of aromatic amines to amides are performed immediately and in excellent yields using triphenylphosphine (PPh3) and 2,3-dichloro-5,6-dicyanobenzoquinone (DDQ) in dichloromethane at room temperature. Symmetrical and unsymmetrical N,N-dialkylation of aromatic amines are also carried out in modest yield at room temperature
π-activation reactions in organic synthesis. In particular, these complexes are characterized by high stability of catalytic species engendered by strong σ-donation and metal backbonding. Herein, we report the synthesis and characterization of well-defined [Au(NHC)Cl] complexes featuring recently discovered IPr# family of ligands that hinge upon modular peralkylation of aniline. These ligands have been
A Dramatic Effect of Aryloxo Ligands on the Titanium-Catalyzed Hydroamination of Alkynes
作者:Vivek Khedkar、Annegret Tillack、Matthias Beller
DOI:10.1021/ol035653+
日期:2003.12.1
[GRAPHICS]The aryloxotitanium complex 1 is a highly chemo- and regioselective catalyst for intermolecular hydroamination of terminal alkynes. Branched imines are obtained in good to excellent yield (up to 99%) with various primary aromatic and aliphatic amines.
A Silver-Catalyzed Domino Route toward 1,2-Dihydroquinoline Derivatives from Simple Anilines and Alkynes
作者:Yumei Luo、Zigang Li、Chao-Jun Li
DOI:10.1021/ol050826b
日期:2005.6.1
[reaction: see text] A silver-catalyzed domino reaction of simple anilines and alkynes generates 1,2-dihydroquinoline derivatives efficiently.