二取代的苯并[ b ]呋喃是通过二氯苯酚和末端炔的邻位选择性Sonogashira偶联反应,然后使用钯-二羟基叔苯基膦(Cy-DHTP)催化剂在一个罐中进行环化和Suzuki-Miyaura偶联反应而合成的。亚化学计量的四丁基氯化铵的使用有效地加速了Suzuki-Miyaura偶联。该方案也成功地用于从二氯苯胺衍生物的一锅法合成二取代的吲哚。
二取代的苯并[ b ]呋喃是通过二氯苯酚和末端炔的邻位选择性Sonogashira偶联反应,然后使用钯-二羟基叔苯基膦(Cy-DHTP)催化剂在一个罐中进行环化和Suzuki-Miyaura偶联反应而合成的。亚化学计量的四丁基氯化铵的使用有效地加速了Suzuki-Miyaura偶联。该方案也成功地用于从二氯苯胺衍生物的一锅法合成二取代的吲哚。
Boron Trichloride‐Mediated Synthesis of Indoles
<i>via</i>
the Aminoboration of Alkynes
作者:Jiahang Lv、Binlin Zhao、Li Liu、Ying Han、Yu Yuan、Zhuangzhi Shi
DOI:10.1002/adsc.201800509
日期:2018.11.5
We describe an efficient catalyst‐ and metal‐free aminoboration of alkynes to 3‐borylated indoles using one of the least expensive boron sources, BCl3. The major dichloro(indolyl)borane products can be used for the in situ construction of useful 3‐Bpin indoles. This simple and mild method provides a novel and efficient approach for the synthesis of various 3‐borylated indoles with high regioselectivity
Catalytic synthesis of indole-3-carboxamides from 2-ethynylanilines and isocyanates was achieved in the presence of a rhodium catalyst through a tandem-type, cyclization–addition sequence. This tandem-type process can be performed under mild reaction conditions, affording 2,3-disubstituted indoles in a one-pot manner generally in good to excellent yields. The broad substrate scope and good functional
Palladium-Catalyzed Cascade Heck Cyclization To Access Bisindoles
作者:Kai Yuan、Lina Liu、Jiayi Chen、Songjin Guo、Hequan Yao、Aijun Lin
DOI:10.1021/acs.orglett.8b01235
日期:2018.6.15
A novel strategy for intercepting the σ-alkylpalladium species generated via a Heck reaction, enabling a palladium-catalyzedcyclization of o-ethynylanilines, has been described. This direct and operationally simple protocol provided a fundamental platform to synthesize bisindoles with high efficiency, involving one C–N bond and two C–C bond formations.
Reaction of 2-phenylethynyl N-tosylanilide prepared by Pd-free procedure with ZnBr(2) (3 equiv) in refluxing toluene gave N-tosyl-2-phenylindole in 93% yield. Treatment of 2-phenylethynylaniline with ZnBr(2) (1 equiv) in refluxing toluene resulted in the formation of 2-phenylindole in 91% yield. Catalytic ZnBr(2) (0.05 equiv) effectively reacted with 2-alkynylanilines to afford 2-substituted indoles in high yields. Thus, complete Pd-free zinc catalyzed hydroamination of 2-alkynylanilines was achieved. (C) 2009 Elsevier Ltd. All rights reserved.
Synthesis of 3-Carboxylated Indoles through a Tandem Process Involving Cyclization of 2-Ethynylanilines Followed by CO<sub>2</sub> Fixation in the Absence of Transition Metal Catalysts
In this study, a facile synthesis of 3-carboxylated indoles involving a tandem-type cyclization of 2-ethynylanilines and subsequent CO2 fixation at the 3-position of the indole ring is realized. The reaction proceeds efficiently at 65 degrees C under 10 atm of CO2, giving rise to variously substituted 3-carboxylated indoles, generally in high yields. An inorganic base, such as K2CO3, is the only reagent required, and the addition of transition metal catalysts is not necessary. The method provides a novel, simple, and promising strategy for CO2 fixation in the research field of heterocyclic chemistry.