Site-Selective Electrophilic Cyclization and Subsequent Ring-Opening: A Synthetic Route to Pyrrolo[1,2-<i>a</i>]quinolines and Indolizines
作者:Trapti Aggarwal、Sonu Kumar、Devendra K. Dhaked、Rakesh K. Tiwari、Prasad V. Bharatam、Akhilesh K. Verma
DOI:10.1021/jo3015374
日期:2012.10.5
An efficient strategy for the synthesis of pyrrolo[1,2-a]quinolines and indolizines from pyranoquinolines via site-selective electrophilic cyclization and subsequent opening of pyran ring using silver/iodine under mild reaction conditions is described. This approach involves the preferential attack of the pyridyl nitrogen over aryl ring and leads to the formation of 5-endo-dig cyclized products. Quantum
描述了一种通过位点选择性亲电环化从吡喃并喹啉合成吡咯并[1,2- a ]喹啉和吲哚嗪的有效策略,随后在温和的反应条件下使用银/碘打开吡喃环。这种方法涉及的吡啶基的氮的优先攻击过的芳环,并导致5-地层内切-挖环化产物。C–N(ΔE a = 9.01 kcal / mol)和C–C(ΔE a为了使观察到的位点选择性合理化,进行= 31.31kcal / mol)的键形成。通过X射线晶体学研究证实了产物的结构。通过Pd催化的交叉偶联反应,通过亲电碘化反应生成的碘取代的化合物进一步多样化。