γ-Regioselective Functionalization of 3-Alkenylindoles<i>via</i>1,6-Addition to Extended Alkylideneindolenine Intermediates
作者:Giulio Bertuzzi、Lucia Lenti、Denisa Giorgiana Bisag、Mariafrancesca Fochi、Marino Petrini、Luca Bernardi
DOI:10.1002/adsc.201701558
日期:2018.3.20
employed key electrophilic intermediates for the α‐functionalization of the C‐3 side chain of indoles. However, the reactivity of their extended (vinylogous) counterparts has not been carefully explored so far. These intermediates can undergo 1,4‐ or 1,6‐addition with functionalization at α‐ or γ‐position of the side chain, resulting in regioisomeric mixtures of products. This work demonstrates that
炔烃亚吲哚胺是吲哚的C-3侧链的α-官能化的广泛使用的关键亲电子中间体。但是,到目前为止,尚未仔细研究其扩展的(葡萄酒)对应物的反应性。这些中间体可以在侧链的α或γ位置进行1,4或1,6加成官能化,生成产物的区域异构混合物。这项工作表明,在3-吲哚-3-基烯丙基醇与各种亲核试剂的反应中,可以实现完全的γ-区域选择性。在室温下,仅1 mol%的三氟甲磺酸锌可催化该过程,并且需要将1,6-亲核试剂选择性地添加到原位生成的扩展质子化的亚烷基亚吲哚烯酮中。吲哚,吡咯,苯胺和硫醇可以有效地用作该反应的亲核伴侣,以中等至良好的产率提供相应的3-乙烯基取代的,γ-官能化的吲哚产物。