The charge-reverse analogy as an inspiration for the preparation of polydentate Lewis acidic boranes
The charge-reverse analogy as an inspiration for the preparation of polydentate Lewis acidic boranes
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DOI：
10.1002/anie.200301630
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发表时间：
2003-01-01
影响因子：
16.6
通讯作者：
Gabbaï, FP
中科院分区：
文献类型：
--
作者：
Gabbaï, FP
多官能路易斯酸含有几个路易斯酸性中心，可以很容易地接受来自到来的碱性底物的电子对。[1]因此，它们的化学性质与多官能路易斯碱相反，后者在其分子骨架中结合了给定数量的可用于配位亲电底物的Lewis碱性中心(方案1)。这一类比在近40年前被施赖弗和比亚拉斯认可，他们发现甲氧基阴离子有效地被乙二胺的电荷反转类似物1，2-双(二氟硼基)乙烷(1)所络合。[2]虽然全球长期的研究工作将多齿刘易斯建立在我们的化学传统的表格上，但多齿刘易斯酸的化学仍处于初级阶段。这些多齿路易斯酸的缓慢出现，至少部分是由于与它们的合成有关的困难。这类化合物在分子识别、材料合成和催化等领域有着广阔的应用前景，引起了人们越来越大的兴趣。为了更好地控制它们作为配体的性质，人们在这些化合物的结构设计上投入了大量精力，并对Lewis酸性中心的电子和空间环境进行了微调。在这方面，最近作为2，2-о-联吡啶类似物的2，2-о-二硼联苯[3]的制备是一项值得注意的成就，将在这一重点中介绍。
Polyfunctional Lewis acids contain several Lewis acidic sites that can readily accept electron pairs from incoming basic substrates.[1] Thus, their chemical nature is the reverse of polyfunctional Lewis bases, which incorporate in their molecular skeleton a given number of Lewis basic sites available for coordination of electrophilic substrates (Scheme1). This analogy was recognized almost four decades ago by Shriver and Biallas, who showed that methoxide anions are effectively chelated by 1, 2-bis (difluoroboryl) ethane(1), a charge-reverse analogue of ethylenediamine [Eq.(1)].[2] While a global and long standing research effort engraved polydentate Lewis bases on the tables of our chemical tradition, the chemistry of polydentate Lewis acids remains in its infancy. The slow emergence of these polydentate Lewis acids results, at least in part, from the difficulties associated with their syntheses. With promising applications in the fields of molecular recognition, material synthesis, and catalysis, this class of compounds is generating an increased interest. By aiming at a greater control of their properties as ligands, much effort has been placed on the architectural design of these compounds, along with a fine-tuning of the electronic and steric environments of the Lewis acidic centers. In this regard, the recent preparation of 2, 2о-diborabiphenyl [3] as an analogue of 2, 2о-bipyridine constitutes a noticeable achievement, which will be presented in this highlight.