Synthesis of 5-Iodopyrrolo[1,2-a]quinolines and Indolo[1,2-a]quinolines via Iodine-Mediated Electrophilic and Regioselective 6-endo-dig Ring Closure
摘要:
The endo-cyclic ring closure of 1-(2-(substituted ethynyl)pheny1)-1H-pyrroles 3a-t and 1-(2-(substituted ethynyl)phenyl)-H-indole 4a-o mediated by Lewis acid (I-2) under mild conditions afforded substituted 5-iodopyrrolo[1,2-a]quinolines 5a-t and 5-iodoindolo[1,2-a]quinolines 6a-o in good to excellent yields. The reaction shows selective C-C bond formation on the more electrophilic alkynyl carbon, resulting in the regioselective 6-endo-dig-cyclized product. Iodo derivatives of pyrrolo- and indoloquinolines allow functional group diversification on the quinoline nucleus, which proves to be highly advantageous for structural and biological activity assessments.
2-(1-Benzotriazolyl)pyridine: A Robust Bidentate Ligand for the Palladium-Catalyzed CC (Suzuki, Heck, Fujiwara-Moritani, Sonogashira), CN and CS Coupling Reactions
作者:Akhilesh K. Verma、Rajeev R. Jha、Ritu Chaudhary、Rakesh K. Tiwari、Abhinandan K. Danodia
DOI:10.1002/adsc.201200583
日期:2013.2.1
designed and employed for the palladium-catalyzed CC (Suzuki, Heck, Fujiwara–Moritani, and Sonogashira), CN and CS coupling reactions. The ligand was found to be inexpensive, thermally stable, easy to synthesize from easily accessible starting materials on a multigram scale, show simplicity in use, and robustness in application, making this ligand effective for different coupling reactions. Suitably, the
设计了一种新型的双齿配体1-(吡啶-2-基)-1 H-苯并[ d ] [1,2,3]三唑,并用于钯催化的CC(Suzuki,Heck,Fujiwara– Moritani和Sonogashira),CN和CS偶联反应。发现该配体便宜,热稳定,易于以几克规模由容易获得的起始原料合成,显示出使用简单性和在应用中的坚固性,从而使该配体对于不同的偶联反应有效。适当地,苯并三唑环的NN键的供体能力和吡啶环的N上的孤对电子增强了配体的二齿能力。
One‐Pot Gold/Acid‐Catalyzed Synthesis of Indolo[1,2‐a]quinolin‐5(6H)‐ones from 1‐(2‐Ethynylphenyl)‐1H‐indoles
The synthesis of substituted indolo[1,2-a]quinoline-5(6H)-ones starting from 1-(2-ethynylphenyl)-1H-indoles is presented. The method involves gold-catalyzed oxidation of the triple bond followed by an acid-promoted intramolecular cyclization at the indole C-2 position.