Organocatalytic Enantioselective Friedel-Crafts Alkylation/Lactonization Reaction of Hydroxyindoles with Methyleneoxindoles
作者:Mengjie Xiao、Dengfeng Xu、Weihong Liang、Wenyu Wu、Albert S. C. Chan、Junling Zhao
DOI:10.1002/adsc.201701089
日期:2018.3.1
Functionalization of the indole benzene ring was achieved by using an organocatalyticenantioselectiveFriedel–Crafts alkylation/lactonization reaction of hydroxyindoles with a variety of substituted methyleneoxindoles. This reaction was applicable to indoles substituted with the hydroxy group at different positions of the benzene ring, and the corresponding pyrrolodihydrocoumarins were obtained in
Organocatalytic enantioselective conjugate addition of nitroalkanes to trifluoromethylated 3-methyleneoxindoles
作者:Wen-Bing Qin、Qinxin Lou、Wei Xiong、Guo-Kai Liu
DOI:10.1016/j.tetlet.2020.152443
日期:2020.10
A bifunctional squaramide catalyzed asymmetric conjugate addition of nitroalkanes to trifluoromethylated 3-methyleneoxindoles was developed, and a range of trifluoromethyl containing oxindole derivatives were obtained with generally high yields and enantioselectivities. The nitro functionality and oxindole scaffold in the corresponding products are versatile buildingblocks that readily enable many
Organocatalytic Friedel-Crafts Alkylation/Lactonization Reaction of Naphthols with 3-Trifluoroethylidene Oxindoles: The Asymmetric Synthesis of Dihydrocoumarins
Naphthols and 3‐trifluoroethylidene oxindoles were found to undergo an asymmetric Friedel–Crafts alkylation/lactonization reaction, catalyzed by only 2.5 mol % of a quinine‐derived squaramide catalyst, to afford the corresponding α‐aryl‐β‐trifluoromethyl dihydrocoumarin derivatives in high yields (up to 99 %) with excellent enantio‐ and diastereoselectivities (up to 98 % ee, >20:1 d.r.). Importantly
Asymmetric [3 + 3] Annulation to Construct Trifluoromethylated Pyrazolo[3,4-<i>b</i>]pyridin-6-ones via Chiral Phosphoric Acid and MgSO<sub>4</sub> Synergistic Catalysis
作者:Alemayehu Gashaw Woldegiorgis、Zhao Han、Xufeng Lin
DOI:10.1021/acs.orglett.2c01513
日期:2022.6.10
and diastereoselectivesynthesis of pyrazolo[3,4-b]pyridin-6-ones bearing a −CF3 unit via synergistic chiral phosphoric acid and MgSO4 catalysis. This [3 + 3] annulation protocol allows the formation of trifluoromethylated pyrazolo[3,4-b]pyridin-6-ones with two adjacent tertiary stereocenters in moderate to high yields (up to 90%), enantioselectivities (up to 97% ee), and diastereoselectivities (up
我们开发了一种新颖的不对称 Friedel-Crafts 烷基化/转酰胺基串联反应,用于通过协同手性磷酸和 MgSO 4催化合成带有 -CF 3单元的吡唑并[3,4- b ]吡啶-6-酮的对映选择性和非对映选择性。这种 [3 + 3] 环化方案允许以中等至高产率(高达 90%)、对映选择性(高达 97% ee ) 和非对映选择性(高达 >20:1 dr)。
New stable reagents for the nucleophilic trifluoromethylation. Part 2: Trifluoromethylation with silylated hemiaminals of trifluoroacetaldehyde
作者:T Billard、B.R Langlois*、G Blond
DOI:10.1016/s0040-4039(00)01552-5
日期:2000.11
New reagents for the nucleophilic trifluoromethylation have been easily synthesized from fluoral hemiketal. They provide silylated trifluoromethylcarbinol from non-enolizable carbonyl compounds. (C) 2000 Elsevier Science Ltd. All rights reserved.