Synthesis of corrole derivatives through regioselective Ir-catalyzed direct borylation
Synthesis of corrole derivatives through regioselective Ir-catalyzed direct borylation
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DOI：
10.1002/anie.200502335
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发表时间：
2005-01-01
影响因子：
16.6
通讯作者：
Osuka, A
中科院分区：
文献类型：
--
作者：
Hiroto, S;Hisaki, I;Osuka, A
corrole是一种含有直接吡咯-吡咯键的18 π芳四吡咯大环，具有有趣的光学性质和独特的金属配位化学性质，是氧化催化的理想配体尽管从开发新型功能材料和分子器件的角度来看，共价连接的多卟啉分子受到了广泛的关注，但由于缺乏有效的合成策略对其进行区域选择性修饰，基于共价连接的多卟啉分子组装的合成仍然相当有限因此，已经作出了相当大的努力，以发展选择性的方法，使corrole有效功能化。然而，在C3位置上可以发生亲电取代，有时会形成多取代产物据我们所知，在C2位置的选择性衍生化还没有报道。最近，我们报道了在铱催化下卟啉β位的高区域选择性直接硼化反应。[5,6]在此，我们成功地将该策略应用于5,10,15 -三芳基对应体，使对应体结构易于在2位功能化，具有完美的区域选择性。由于有机硼烷的丰富化学性质，该策略为构建基于腐蚀的分子组件提供了强大的工具。在[Ir (cod) OMe] 2 （1.5 mol%）和4,4 ' -二叔丁基- 2,2 ' -联吡啶（3.0 mol%）的催化量(miyura - hartwigh - smith协议（方案1）存在下，用二恶烷中的5,10,15 -三（五氟苯基）corro2(1)[7]溶液（1.1等量）在1008℃下加热24 h。[5,6b]制备型GPC-HPLC纯化得到的单溴化corro2的收率为91%
Corroles are 18-π-aromatic tetrapyrrolic macrocycles that contain a direct pyrrole–pyrrole linkage, that exhibit interesting optical properties and unique metal-coordination chemistry, and serve as excellent ligands for oxidation catalysis.[1] Although covalently linked multiporphyrinic molecules have received much attention from the viewpoint of the development of novel functional materials and molecular devices,[2] the synthesis of molecular assemblies based on corroles has remained rather limited owing to the lack of effective synthetic strategies for their regioselective modification.[3] Thus, considerable efforts have been made to develop selective methods that allow the effective functionalization of corroles. However, electrophilic substitution of corroles can occur at the C3 position, and multisubstitution products are sometimes formed.[4] To the best of our knowledge, the selective derivatization of corroles at the C2 position has not been reported. Very recently, we reported the highly regioselective direct borylation of porphyrins at the β position under iridium catalysis.[5, 6] Herein, we disclose the successful application of this strategy to 5, 10, 15-triarylcorroles which enables easy functionalization of the corrole structure at the 2-position with perfect regioselectivity. Owing to the rich chemistry of organoboranes, this strategy offers a powerful tool for the construction of corrole-based molecular assemblies.A solution of 5, 10, 15-tris (pentafluorophenyl) corrole (1)[7] in dioxane was heated at 1008C for 24 h with bis (pinacolato) diborane (1.1 equiv) in the presence of a catalytic amount of [Ir (cod) OMe] 2 (1.5 mol%) and 4, 4’-di-tert-butyl-2, 2’-bipyridyl (dtbpy; 3.0 mol%) according to the Miyaura–Hartwig–Smith protocol (Scheme 1).[5, 6b] Purification by preparative GPC-HPLC afforded the monoborylated corrole 2 in 91%