suzuki-miyaura reactions catalyzed by c2-symmetric pd-multi-dentate n-heterocyclic carbene complexessuzuki-miyaura反应催化由c2-symmetric pd-multi-dentate氮杂卡宾配合物.pdf

Molecules 2012, 17, 12121-12139; doi:10.3390/molecules171012121 OPEN ACCESS molecules ISSN 1420-3049 /journal/molecules Article Suzuki-Miyaura Reactions Catalyzed by C -Symmetric 2 Pd-Multi-Dentate N-Heterocyclic Carbene Complexes Lan Jiang 1,2, Fengjun Shan 2, Zhengning Li 2,* and Defeng Zhao 1,* 1 State Key Laboratory of Fine Chemicals, Dalian University of Technology, Dalian 116024, China; E-Mail: jianglan@ 2 College of Environmental and Chemical Engineering, Dalian University, Dalian 116622, China; E-Mail: sfj225@126.com * Authors to whom correspondence should be addressed; E-Mails: znli@ (Z.L.); zhaodfg@ (D.Z.); Tel.: +86-411-8740-3576 (Z.L.); Fax: +86-411-8740-2449 (Z.L.). Received: 20 September 2012; in revised form: 6 October 2012 / Accepted: 9 October 2012 / Published: 16 October 2012 Abstract: Suzuki-Miyaura coupling reactions are promoted by Pd complexes ligated with C -symmetric multi-dentate N-heterocyclic carbenes derived in situ from Pd(OAc) 2 2 and imidazolium salts. Good to excellent yields were obtained for aryl bromides as substrates. Turnover numbers of up to 105 could be achieved with 5 × 10−4 mol% of Pd(OAc) /1 × 10−3 mol% NHC precatalyst in 24 h. 2 Keywords: imidazolium salt; N-heterocyclic carbene; palladium; Suzuki-Miyaura coup