Plancher; Piccinini, Atti della Accademia Nazionale dei Lincei, Classe di Scienze Fisiche, Matematiche e Naturali, Rendiconti, 1905, vol. <5> 14 II, p. 40
Highly functionalized oxazinanes are efficiently prepared through urea-catalyzed formal [3 + 3] cycloaddition reactions of nitrones and nitrocyclopropane carboxylates. The reaction system is general with respect to both the nitrocyclopropane carboxylates and nitrones enabling the preparation of a large family of oxazinanes, typically in high yield. This method affords access to enantioenriched oxazinane products through chirality transfer from enantioenriched nitrocyclopropane carboxylates.
An enantioselective Mannich‐type reaction of 3‐butynol and nitrones is described, which affords dihydrofuran‐3‐ones in good yields and with excellent enantioselectivities. The reaction is initiated by gold‐catalyzed alkyne oxidation and modification of the resulting gold carbene species with a tethered hydroxy group to form enolate species; the reaction terminates with an enantioselective Mannich‐type
Facile Synthesis of Fully Substituted Dihydro-β-carbolines via Brønsted Acid Promoted Cascade Reactions of α-Indolyl Propargylic Alcohols with Nitrones
作者:Lu Wang、Xin Xie、Yuanhong Liu
DOI:10.1021/ol302695p
日期:2012.12.7
Brønsted acid promoted cyclizations of α-indolyl propargylic alcohols with nitrones is described. The use of nitrones bearing alkenyl or electron-rich aryl groups as the R4 substituent dramatically switches the reaction pathway to afford tetrasubstituted alkenes and amines, which is assumed to proceed through a rearrangement reaction involving N–O bond cleavage and 1,2-migration of the R4 group to an adjacent
Selective Cyclization of Arylnitrones to Indolines under External Oxidant-Free Conditions: Dual Role of Rh(III) Catalyst in the C–H Activation and Oxygen Atom Transfer
作者:Ramesh B. Dateer、Sukbok Chang
DOI:10.1021/jacs.5b01065
日期:2015.4.22
The first example of Rh(III)-catalyzed cyclization of arylnitrones to indolines under external oxidant-free conditions is presented. An intermolecular coupling of arylnitrones with internal alkynes is made possible by the dual role of the Cp*Rh(III) catalyst mediating both the C-H bond activation and O-atom transfer. Synthetically important and pharmacologically privileged indoline derivatives were obtained
介绍了在无外部氧化剂条件下,Rh(III) 催化芳基硝酮环化成二氢吲哚的第一个例子。Cp*Rh(III) 催化剂在介导 CH 键活化和 O 原子转移的双重作用下,使芳基硝酮与内部炔烃的分子间偶联成为可能。以良好的收率和高非对映选择性获得了合成上重要且药理学上有特权的二氢吲哚衍生物。
Enantioselective Oxidative Multi-Functionalization of Terminal Alkynes with Nitrones and Alcohols for Expeditious Assembly of Chiral α-Alkoxy-β-amino-ketones
functionalization of alkynes has emerged as an effective method in synthetic chemistry in recent decades. However, enantioselective transformations via metal carbene intermediates are quite rare due to the lack of robust chiralcatalysts, especially in the intermolecular versions. Herein, we report the first asymmetric three-component reaction of commercially available alkynes with nitrones and alcohols, which affords