Nitroepoxides as Versatile Precursors to 1,4-Diamino Heterocycles
摘要:
Nitroepoxides are easily transformed into 1,4-diamino heterocycles such as quinoxalines and pyrazines by treatment with 1,2-benzenediamines and ammonia, respectively. Additionally, related saturated heterocycles, such as piperazines and tetrahydroquinoxalines, can be accessed by treatment with 1,2-diamines and a reducing agent. These transformations are efficient, provide access privileged, bioactive structures, and produce minimal waste.
Synthesis of (E)-nitro olefins by isomerisation of (Z)-nitro olefins with polymer-supported triphenylphosphine
摘要:
We have found that (Z)-nitro olefins or mixtures of (E)- and (Z)-compounds can be converted to the pure (E)-isomers by treatment with catalytic amounts of triethylamine or polymer-bound triphenylphosphine, respectively. (C) 1998 Elsevier Science Ltd. All rights reserved.
common and versatile reagent. Its synthesis from olefin is generally limited by the formation of mixture of cis and trans compounds. Here we report that silver nitrite (AgNO2) along with TEMPO can promote the regio- and stereoselective nitration of a broad range of olefins. This work discloses a new and efficient approach wherein starting from olefin, nitroalkane radical formation and subsequent transformations
硝基烯烃是一种常见且用途广泛的试剂。它从烯烃合成通常受到顺式和反式化合物混合物的形成的限制。在这里,我们报告亚硝酸银 (AgNO2) 与 TEMPO 一起可以促进范围广泛的烯烃的区域和立体选择性硝化。这项工作公开了一种新的有效方法,其中从烯烃开始,硝基烷烃自由基形成和随后的转化以立体选择性方式导致所需的硝基烯烃。
Dynamic Kinetic Asymmetric Ring-Opening/Reductive Amination Sequence of Racemic Nitroepoxides with Chiral Amines: Enantioselective Synthesis of Chiral Vicinal Diamines
作者:Juan Agut、Andreu Vidal、Santiago Rodríguez、Florenci V. González
DOI:10.1021/jo400501k
日期:2013.6.7
We report a highly diastereoselective synthesis of vicinaldiamines by the treatment of nitroepoxides with primary amines and then a reducing agent. When using a chiral primary amine, racemic nitroepoxides are transformed into chiral diamines as a single enantiomers (>95:5 er) through a dynamic kinetic asymmetric transformation (DYKAT). The overall process is a one-pot procedure combining the exposure
Regioselective Opening of Nitroepoxides with Unsymmetrical Diamines
作者:Yazdanbakhsh L. Nosood、Azim Ziyaei Halimehjani、Florenci V. González
DOI:10.1021/acs.joc.7b02795
日期:2018.2.2
by treatment with 2-aminobenzylamines, 2-aminopyridines, and N-alkyl 1,2-diaminobenzenes, respectively. Regioselectivity is controlled through attack of the most nucleophilic nitrogen of the unsymmetricaldiamine to the β position of the epoxide. These reactions represent an efficient way to prepare privileged bioactive structures.
Trisubstituted alkenes with a single activator as dipolarophiles in a highly diastereo- and enantioselective [3+2] cycloaddition with vinyl epoxides under Pd-catalysis
which are unreactive electron-deficient alkenes in transition metal-catalyzed [3+2] cycloaddition with vinyl three-membered heterocycles, were used in the Pd-catalyzed asymmetric cycloaddition of vinyl epoxides, affording multifunctionalized tetrahydrofurans in high yields with high diastereo- and enantioselectivities.