Iron-Catalyzed Ortho C-H Methylation of Aromatics Bearing a Simple Carbonyl Group with Methylaluminum and Tridentate Phosphine Ligand
Iron-Catalyzed Ortho C-H Methylation of Aromatics Bearing a Simple Carbonyl Group with Methylaluminum and Tridentate Phosphine Ligand
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DOI：
10.1021/jacs.6b06908
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发表时间：
2016-08-17
影响因子：
15
通讯作者：
Nakamura, Eiichi
中科院分区：
文献类型：
--
作者：
Shang, Rui;Ilies, Laurean;Nakamura, Eiichi
近年来，铁催化的芳香族C-H官能化反应引起了化学家的广泛关注，而对底物上精细导向基团的需求迄今阻碍了简单芳香族羰基化合物如苯甲酸和酮的使用，大大降低了其合成效用。本文描述了一种温和反应性的甲基铝试剂和一种新的用于金属催化的三齿膦配体4-（双（2-（二苯基膦基）苯基）膦基）-N，N-二甲基苯胺（Me_2N-TP）的组合，它允许我们在温和的氧化条件下将带有简单羰基的芳族化合物和杂芳族化合物中的邻位CH键转化为C-CH_3键。该反应的强度足以甲基化二苯甲酮中的所有四个邻位C-H键。该反应容许多种官能团，如硼酸酯、卤化物、硫化物、杂环和可烯醇化的酮。
Iron-catalyzed C-H functionalization of aromatics has attracted widespread attention, from chemists in recent years, while the requirenien( of an elaborate directing group on the substrate has so far hampered the use of simple aromatic carbonyl compounds such as benzoic acid and ketones, much reducing its synthetic utility. We describe here a combination of a mildly reactive' methylaluminum reagent and a new tridentate phosphine ligand for metal catalysis, 4-(bis(2-(diphenylphosphanyl)phenyl)phosphany1)-N,N-dimethyl- aniline (Me2N-TP), that allows us to convert an ortho C H bond to a C-CH3 bond in aromatics and heteroaromatics bearing simple carbonyl groups under mild oxidative conditions. The reaction is powerful enough to methylate all four ortho C-H bonds in benzophenone. The reaction tolerates a variety of functional groups, such as boronic ester, halide, sulfide, heterocycles, and enolizable ketones.