配体促进卡宾插入钌基复分解催化剂中N-杂环卡宾配体的芳基取代基。

Ligand-promoted carbene insertion into the aryl substituent of an N-heterocyclic carbene ligand in ruthenium-based metathesis catalysts.

作者信息

Galan Brandon R, Pitak Mateusz, Gembicky Milan, Keister Jerome B, Diver Steven T

机构信息

Department of Chemistry, University at Buffalo, the State University of New York, Buffalo, New York 14260-3000, USA.

出版信息

J Am Chem Soc. 2009 May 20;131(19):6822-32. doi: 10.1021/ja809984k.

DOI:10.1021/ja809984k

PMID:19397262

Abstract

Addition of L = carbon monoxide or aryl isocyanides to the Grubbs second-generation carbene complexes Ru(H(2)IMes)(CHR)(PCy(3))Cl(2) (H(2)IMes = 1,3-dimesityl-4,5-dihydroimidazol-2-ylidene; R = Ph, Me, H, CH=CMe(2)) triggers carbene insertion into an aromatic ring of the N-heterocyclic carbene supporting ligand, forming Ru{1-mesityl-3-(-7'-R-2',4',6'-trimethylcycloheptatrienyl)-4,5-dihydroimidazol-2-ylidene}L(2)(PCy(3))Cl(2). Insertions are also promoted for other PR(3) substituted complexes by carbon monoxide and aryl isocyanides, and for the phosphine-free Hoveyda-Blechert complex Ru(H(2)IMes)(CH(i-PrOC(6)H(4)))Cl(2) by aryl isocyanides and small phosphites but only after initial displacement of the coordinated ether. Heteroatom substituted carbenes do not undergo CO-promoted insertion unless poorer electron donor phosphine (PPh(3)) and carbene (CH(OC(6)H(4)-p-NO(2)) ligands are both present. Insertion depends on the added ligand, the carbene substituent, and to a lesser degree on the PR(3) ligand trans to the N-heterocyclic carbene.

摘要

向Grubbs第二代卡宾配合物Ru(H₂IMes)(CHR)(PCy₃)Cl₂（H₂IMes = 1,3 - 二甲基苯基 - 4,5 - 二氢咪唑 - 2 - 亚基；R = Ph、Me、H、CH = CMe₂）中加入L = 一氧化碳或芳基异腈，会引发卡宾插入到N - 杂环卡宾支撑配体的芳环中，形成Ru{1 - 甲基苯基 - 3 - (-7'-R - 2',4',6'-三甲基环庚三烯基)-4,5 - 二氢咪唑 - 2 - 亚基}L₂(PCy₃)Cl₂。一氧化碳和芳基异腈也能促进其他PR₃取代配合物的插入反应，对于无膦的Hoveyda - Blechert配合物Ru(H₂IMes)(CH(i - PrOC₆H₄))Cl₂，芳基异腈和小的亚磷酸酯能促进插入反应，但前提是先取代配位的醚。除非同时存在给电子能力较差的膦（PPh₃）和卡宾（CH(OC₆H₄ - p - NO₂)）配体，否则杂原子取代的卡宾不会发生CO促进的插入反应。插入反应取决于所加入的配体、卡宾取代基，并且在较小程度上取决于与N - 杂环卡宾反位的PR₃配体。