College of Chemistry and Chemical Engineering, Yangzhou University , Yangzhou 225002, China.
J Org Chem. 2017 Dec 15;82(24):13277-13287. doi: 10.1021/acs.joc.7b02397. Epub 2017 Nov 27.
TfOH-catalyzed one-pot sequential reaction of indoles, acetophenones (cyclic ketones), and various 3-methyleneoxindolines in toluene afforded polysubstituted tetrahydrospiro[carbazole-1,3'-indoline]s in satisfactory yields. H NMR spectra and single-crystal structures indicated that the obtained tetrahydrospiro[carbazole-1,3'-indoline]s existing in an unusual trans-configuration. The reaction mechanism was believed to proceed with domino acid-catalyzed 3-alkenylation of indoles with acetophenones, Diels-Alder reaction of 3-alkyenylindoles with 3-methyleneoxindolines, and an acid-catalyzed diastereoisomerization process.
三氟甲磺酸铯催化吲哚、苯乙酮（环状酮）和各种 3-亚甲基氧化吲哚在甲苯中的一锅法串联反应以令人满意的收率得到了多取代的四氢螺[咔唑-1,3'-吲哚]。核磁共振谱和单晶结构表明，得到的四氢螺[咔唑-1,3'-吲哚]以一种不寻常的反式构型存在。反应机理被认为是通过吲哚与苯乙酮的酸催化 3-烯丙基化、3-烯丙基吲哚与 3-亚甲基氧化吲哚的 Diels-Alder 反应以及酸催化的非对映异构体化过程进行的。
