PDF(Pubmed)
Abstract：
Electron-rich heteroaromatics, such as furan, thiophene and pyrrole, as well as their benzo-condensed derivatives, are of great interest as components of natural products and as starting substances for various products including high-tech materials. Although their reactions with Brønsted and Lewis acids play important roles, in particular as the primary step of various transformations, they are often disregarded and mechanistically not understood. The present publication gives a first overview about this chemistry focusing on the parent compounds. It comprises reactions with strong Brønsted acids forming adducts that can undergo intramolecular proton and/or substituent transfer reactions, ring openings or ring transformations into other heterocycles, depending on their structure. Interactions with weak Brønsted acids usually initiate oligomerizations/polymerizations. A similar behaviour is observed in reactions of these heteroaromatics with Lewis acids. Special effects are achieved when the Lewis acids are activated through primary protonation. Deuterated Brønsted acids allow straight forward deuteration of electron-rich heteroaromatics. Mercury salts as extremely weak Lewis acids cause direct metalation in a straight forward way replacing ring H-atoms yielding organomercury heterocycles. This review will provide comprehensive information about the chemistry of adducts of such heterocycles with Brønsted and Lewis acids enabling chemists to understand the mechanisms and the potential of this field and to apply the findings in future syntheses.
摘要：
富电子杂芳族化合物，比如呋喃,噻吩和吡咯，以及它们的苯并缩合衍生物，作为天然产物的成分和作为包括高科技材料在内的各种产品的起始物质具有极大的兴趣。尽管它们与布朗斯特和路易斯酸的反应起着重要作用，特别是作为各种转变的第一步，他们往往被忽视和机械不理解。本出版物给出了关于集中于母体化合物的该化学的第一概述。它包括与强布朗斯台德酸的反应，形成可以进行分子内质子和/或取代基转移反应的加合物，环开口或环转化为其他杂环，这取决于他们的结构。与弱布朗斯台德酸的相互作用通常引发低聚/聚合。在这些杂芳族化合物与路易斯酸的反应中观察到类似的行为。当路易斯酸通过初级质子化活化时,获得特殊效果。氘代的布朗斯台德酸允许富电子杂芳族化合物的直接向前氘代。汞盐作为极弱的路易斯酸以直接的方式引起直接金属化，取代环H原子，产生有机汞杂环。这篇综述将提供有关此类杂环与布朗斯台德和路易斯酸的加合物化学的全面信息，使化学家能够了解该领域的机制和潜力，并将这些发现应用于未来的合成。
