Suzuki–Miyaura cross-coupling reaction on copper-trans-A₂B corroles with excellent functional group tolerance

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• 作者：Michael Kö ; nig^a ; Lorenz Michael Reith^a ; Uwe Monkowius^a ; Gü ; nther Knö ; r^a ; Klaus Bretterbauer^b ; Wolfgang Schoefberger^a ; ^{wolfgang.schoefberger@jku.at"" rel=""nofollow}
• 关键词：Corrole ; Copper ; Suzuki&#x2013 ; Miyaura coupling reaction ; Pd-catalysts ; Boronic acids/esters ; Density functional theory (DFT) ; Time-dependent DFT
• 刊名：Tetrahedron
• 出版年：2011
• 出版时间：10 June 2011
• 年：2011
• 卷：67
• 期：23
• 页码：4243-4252
• 全文大小：1005 K

文摘

The palladium-catalyzed Suzuki–Miyaura cross-coupling reaction has been investigated on meso-substituted trans-A₂B-corrole using tailored Pd-catalyst systems.

We present the first examples of Suzuki–Miyaura cross-coupling reactions on meso-substituted trans-A₂B-corrole derivatives with neutral, sterically hindered, inactivated and heteroaromatic boronic acids and esters, alkenylboronic acids, as well as quickly deboronating aryl boronic acids and benzo-condensated five membered heterocyclic boronic acids. In addition, we established a high-yield procedure for the Suzuki–Miyaura cross-coupling reaction of corroles with neutral boronic acids.

Due to the lability of the free-base corrole macrocycles, functionalization of the corrole periphery was performed with the corresponding Cu-metallated species. meso-Substituted trans-A₂B-corrole can hence be regarded as highly versatile platform towards more sophisticated corrole systems.

X-ray structure analysis of a functionalized meso-substituted trans-A₂B copper corrole exhibited the typical features of such a Cu-complex: short N–Cu distances and a saddled corrole configuration.

Moreover, we observed a sensitivity of the formal oxidation state of the coordinated copper ions towards Suzuki–Miyaura cross-coupling reaction conditions, where the central copper(III) ion approaches the characteristic features of a copper(II) species. This redox behaviour was examined by UV/vis absorption spectra, nuclear magnetic resonance (NMR) experiments and time-dependent density functional theoretical calculations.