已经建立了吲哚基亚烷基β-酮酸酯与单和二取代的芳基烯烃的钙催化的正式[5 + 2]环加成反应,以形成环庚[ b ]吲哚衍生物。与苯基乙烯基硫醚/醚的意外化学发散表明,双[5 + 2]环加成级联反应提供了乙醇桥联的环庚[ b ]吲哚。总体而言,该方法的亮点包括:(1)使用绿色的钙基催化剂(负载量为2.5摩尔%);(2)反应时间在1小时以下;(3)反应条件温和;(4)底物来源的化学散度;(5)功能组容忍度;(6)衍生化的例子。
The first calcium-catalysed Nazarov cyclisation is described.
第一个以钙催化的Nazarov环化反应被描述了。
Process for reducing 3-heteroaryl-3-oxopropionic acid derivatives
申请人:——
公开号:US20030225274A1
公开(公告)日:2003-12-04
The present invention relates to a process for preparing stereoisomerically enriched 3-heteroaryl-3-hydroxycarboxylic esters by reducing 3-heteroaryl-3-oxocarboxylic esters in the presence of ruthenium-containing catalysts.
Noncanonical Cation−π Cyclizations of Alkylidene β-Ketoesters: Synthesis of Spiro-fused and Bridged Bicyclic Ring Systems
作者:Dylan E. Parsons、Alison J. Frontier
DOI:10.1021/acs.orglett.9b00094
日期:2019.4.5
conditions employed, it is possible to achieve selective synthesis of the three different types of products, including 1-halo-3-carbomethoxycyclohexanes, spiro-fused tricyclic systems, and [4.3.1] bridged bicyclicringsystems. All three reactions begin with 6-endo addition of an olefin to the alkylidene β-ketoester electrophile, followed by one of three different cation capture events.
Herein, we describe the synthesis of a 1,2,4-trisubstituted carbazole core from 5-(1H-indol-3-yl)-3-oxopentanoic acid esters or amides. For oxidative cyclization, we tested two different approaches. First, we used manganese triacetate as a conventional moderate oxidizer to ensure the radical course of the reaction. Second, we examined the use of a more complex oxidizing agent I2/Me(OTf)3. In both cases
The enantioselective total syntheses of (−)-silicine and (−)-20-episilicine, which contain a chiral piperidine with three contiguous chiral centers (D-ring) and a strained seven-membered ring (C-ring) attached to an indole, were achieved. The key steps of these syntheses included a chiral secondary amine-catalyzed formal aza-[3 + 3] cycloaddition reaction and Lewis acid-mediated irreversible ring-closing