Perrin Charles L, Rodgers Betsy L, O'Connor Joseph M
Department of Chemistry and Biochemistry, University of California-San Diego, La Jolla, CA 92093-0358, USA.
J Am Chem Soc. 2007 Apr 18;129(15):4795-9. doi: 10.1021/ja070023e. Epub 2007 Mar 23.
Biosynthesis of haloaromatics ordinarily occurs by electrophilic attack of an activated halogen species on an electron-rich aromatic ring. We now present the discovery of a new reaction whereby a nucleophilic halide anion can be attached even to an aromatic ring without activating substituents. We show that the enediyne cyclodeca-1,5-diyn-3-ene, in the presence of lithium halide and a weak acid, is converted to 1-halotetrahydronaphthalene. The kinetics are consistent with rate-limiting cyclization to a p-benzyne biradical that rapidly adds halide and is then protonated. This reaction has interesting mechanistic features and important implications for incorporation of halide into biomolecules.
卤代芳烃的生物合成通常是通过活化的卤素物种对富电子芳环的亲电攻击来实现的。我们现在报道了一种新反应的发现，即亲核卤离子甚至可以连接到没有活化取代基的芳环上。我们表明，在卤化锂和弱酸存在下，烯二炔环癸-1,5-二炔-3-烯会转化为1-卤代四氢萘。动力学与限速环化生成对苯炔双自由基一致，该双自由基会迅速添加卤离子，然后质子化。该反应具有有趣的机理特征，并且对于将卤化物掺入生物分子具有重要意义。
