Department Chemie, Ludwig-Maximilians-Universität München, Butenandtstrasse 5-13, Haus F, 81377 München (Germany), Fax: (+49) 89-2180-77680.
Chemistry. 2013 Oct 18;19(43):14687-96. doi: 10.1002/chem.201301869. Epub 2013 Sep 11.
A straightforward and efficient alumination of functionalized arenes by using the frustrated Lewis pair Et3 Al and TMPMgCl⋅LiCl (TMP=2,2,6,6-tetramethylpiperidyl) has been developed. In particular, halogenated electron-rich aromatics can be smoothly functionalized by using the frustrated Lewis pair Et3 Al and TMPMgCl⋅LiCl. Compared with previously described alumination methods, this procedure avoids extensive cooling and the need for an excess of base. This in situ procedure has proven to be most practical and allows for regio- and chemoselective metalation of a wide range of aromatics with sensitive functional groups (CONEt2 , CO2 Me, CN, OCONMe2 ) or halogens (F, Cl, Br, I). The resulting aromatic aluminates, which were characterized by using NMR spectroscopy, were subjected to allylations, acylations, and palladium-catalyzed cross-coupling reactions after transmetalation to zinc. It was shown that the nature of the Zn salt used for transmetalation is crucial. Thus, compared with ZnCl2 (2 equiv), the use of Zn(OPiv)2 (2 equiv; OPiv=pivalate) allows the subsequent quenching reactions to be performed with only a slight excess of electrophile (1.2 equiv) and provides interesting functionalized aromatics in good yields.
已开发出一种通过使用受阻路易斯对 Et3 Al 和 TMPMgCl⋅LiCl（TMP=2,2,6,6-四甲基哌啶基）将功能化芳族化合物直接且高效地转化为铝化物的方法。特别是，卤代富电子芳烃可以通过受阻路易斯对 Et3 Al 和 TMPMgCl⋅LiCl 来顺利地进行官能化。与之前描述的铝化方法相比，该方法避免了广泛的冷却和对过量碱的需求。这种原位方法已被证明是最实用的，并允许对具有敏感官能团（CONEt2、CO2Me、CN、OCONMe2 ）或卤素（F、Cl、Br、I）的各种芳烃进行区域和化学选择性的金属化。通过 NMR 光谱对所得芳基铝酸盐进行了表征，然后在向锌进行转金属化后，对其进行烯丙基化、酰化和钯催化交叉偶联反应。结果表明，用于转金属化的 Zn 盐的性质至关重要。因此，与 ZnCl2（2 当量）相比，使用 Zn(OPiv)2（2 当量；OPiv=pivalate）可以仅使用稍过量的亲电试剂（1.2 当量）进行随后的猝灭反应，并以良好的产率提供有趣的功能化芳烃。
