Catalyst- and Substituent-Controlled Switching of Chemoselectivity for the Enantioselective Synthesis of Fully Substituted Cyclobutane Derivatives via 2 + 2 Annulation of Vinylogous Ketone Enolates and Nitroalkene
作者:Pavan Sudheer Akula、Bor-Cherng Hong、Gene-Hsiang Lee
DOI:10.1021/acs.orglett.8b03335
日期:2018.12.21
The first regioselective, diastereoselective, and enantioselective organocatalyzed Michael–Michael cascade of vinylogous ketone enolates and nitroalkenes for the construction of fully substituted cyclobutanes is achieved by the deployment of the appropriate chiral squaramide catalyst and the pertinent substituent on the substrate. The dominoreaction provided cyclobutanes with four contiguous stereocenters
Catalytic enantioselective epoxidation of nitroalkenes
作者:A. Vidal-Albalat、K. Świderek、J. Izquierdo、S. Rodríguez、V. Moliner、F. V. González
DOI:10.1039/c6cc03539f
日期:——
Nitroepoxides are potentially exploitable as synthons with vicinal electrophilic centers. Nevertheless, although advances have been made in the field, enantioselective epoxidation of nitroalkenes is still a challenging process. Herein we...
Nitronate-aryne cycloaddition as a concise route to stereochemically complex fused benzisoxazolines and amino alcohols
作者:Alexander A. Lukoyanov、Andrey A. Tabolin、Yulia V. Nelyubina、Svetlana A. Aksenova、Alexey Yu. Sukhorukov
DOI:10.1039/d3ob00235g
日期:——
The reaction of cyclic nitronates (isoxazoline N-oxides and 5,6-dihydro-4H-1,2-oxazine N-oxides) with Kobayashi's aryneprecursors affords tricyclic benzene-fused nitroso acetals as a result of [3 + 2]-cycloaddition. The process is regio- and stereoselective in most cases and produces the target cycloadducts possessing up to four contiguous stereogenic centers. These nitroso acetals were shown to be
环状硝酸酯(异恶唑啉N-氧化物和5,6-二氢-4 H -1,2-恶嗪N)的反应-氧化物)与 Kobayashi 的芳炔前体通过 [3 + 2]-环加成反应得到三环苯稠合亚硝基缩醛。在大多数情况下,该过程具有区域选择性和立体选择性,并产生具有多达四个连续立体中心的目标环加合物。通过 N-O 键的催化氢解,这些亚硝基缩醛被证明是有价值的多取代氨基二醇的方便前体。此外,质子酸的作用通过异质 N-O 键断裂和贝克曼型反应导致环状亚硝基缩醛部分异常断裂。使用这种酸介导的反应,完成了迄今为止未知的六氢苯并[4,5]异恶唑并[2,3- a ]氮杂支架的合成。
An efficient synthesis of (E)-nitroalkenes catalyzed by recoverable diamino-functionalized mesostructured polymers
A clean, efficient, and simple method has been developed for synthesis of (E)-nitroalkenes using FDU-ED as an efficient catalyst. The reactions proceeded with moderate to high yields (60-96%) under mild conditions. The catalyst FDU-ED is recyclable and can be reused more than seven times without significant loss of activity and selectivity. (C) 2008 Elsevier Ltd. All rights reserved.
Consecutive Cycloaddition/S<sub>N</sub>Ar/Reduction/Cyclization/Oxidation Sequences: A Copper-Catalyzed Multicomponent Synthesis of Fused N-Heterocycles
A highly efficient multicomponent domino protocol has been developed for the synthesis of 5-phenyl-[1,2,3]triazolo[1,5-c]quinazolines from simple and readily available (E)-1-bromo-2-(2-nitrovinyl)benzenes, aldehydes, and sodium azide. This elegant domino process involved consecutive [3 + 2] cycloaddition, copper-catalyzed SNAr, reduction, cyclization, and oxidation sequences. Notably, sodium azide acted as a dual nitrogen source in the construction of this novel fused N-heterocycle.