Pd(0)-Catalyzed Intramolecular Heck reaction of 2/3-Aryl(amino)methyl-3/2-bromoindoles: Syntheses of 3,4-Benzo[<i>c</i>]-β-carbolines, Benzo[4,5]isothiazolo[2,3-<i>a</i>]indole 5,5-Dioxides, and 1,2-Benzo[<i>a</i>]-γ-carbolines
作者:Potharaju Raju、Velu Saravanan、Vinayagam Pavunkumar、Arasambattu K. Mohanakrishnan
DOI:10.1021/acs.joc.0c02152
日期:2021.1.15
One-pot synthesis of 3,4-benzo[c]-β-carbolines was achieved from 2-aryl(tosylamino)methyl-3-bromoindoles via 10 mol % Pd(OAc)2/PPh3-mediated intramolecular Heck coupling using K2CO3 as a base in DMF at 110 °C with concomitant aromatization through an elimination of tosylsulfinic acid. Under identical conditions, the isomeric 3-aryl(tosylamino)methyl-2-bromoindoles upon intramolecular Heck reaction furnished
通过10 mol%Pd(OAc)2 / PPh 3介导的分子内Heck偶联反应,由2-芳基(甲苯磺酰基氨基)甲基-3-溴吲哚完成了一锅合成3,4-苯并[ c ]-β-咔啉在110°C的DMF中以2 CO 3为碱,同时伴随有通过去除甲苯磺酰基亚磺酸进行的芳构化。在相同条件下,分子内Heck反应的异构体3-芳基(甲苯磺酰基氨基)甲基-2-溴吲哚提供了苯并[4,5]异噻唑并[2,3 - a ]吲哚5,5-二氧化物,而不是预期的γ-咔啉。然而,合成了预期的γ-咔啉骨架,3-甲苯基-6,9-二氢-1,2-苯并[ a]]-γ-咔啉可以从在吲哚氮上含有1,3,5-苯三甲磺酰基单元作为保护基的3-芳基(甲苯磺酰基氨基)甲基-2-溴吲哚获得。