Access to a Cationic, Electron-Poor N-Heterocyclic Carbene with a Quinazolinium Core by Postsynthetic Modification of Related Neutral Derivatives

被引：10

作者：

Brueggemann, Peter ^{[1
]}

Wahl, Michaela ^{[1
]}

Schwengers, Sebastian ^{[1
]}

Buhl, Hannes ^{[1
]}

Ganter, Christian ^{[1
]}

机构：

[1] Heinrich Heine Univ Dusseldorf, Abt Metallorgan Chem, Inst Anorgan Chem, Univ Str 1, D-40225 Dusseldorf, Germany

来源：

ORGANOMETALLICS | 2018年 / 37卷 / 22期

关键词：

RHODIUM(I) COMPLEXES; BACKBONE SYNTHESIS; REACTIVITY; CATALYSIS;

D O I：

10.1021/acs.organomet.8b00615

中图分类号：

O61 [无机化学];

学科分类号：

070301 ; 081704 ;

摘要：

Derivatives of cationic six-membered N-heterocyclic carbene G with a quinazolinium scaffold are easily obtained by abstraction of an alcoholate group from related neutral precursors which are easily accessible. On the basis of this route, chalcogene adducts and metal complexes of G, which is a benzo-anellated pyrimidiniumylidene, could be prepared. Evaluation of the ligand properties by IR and Se-77 NMR spectroscopy indicate that cationic carbene G is a much more powerful pi-acceptor (delta(Se-77): 768 ppm) and a significantly weaker overall donor (TEP: 2073 cm(-1)) than related neutral carbene 4 (361 ppm, 2054 cm(-1)). DFT calculations provide a rationale for these experimental observations. AuCI complexes of both carbenes were used as catalysts for the cyclization of a propargylamide to a methyleneoxazoline. The complex containing the cationic carbene featured a much higher activity.

引用

页码：4276 / 4286

页数：11