A metal-free convenient synthesis of 4,5-disubstituted N-unsubstituted 1,2,3-triazoles via a cycloaddition–denitration process has been described. A variety of readily available nitroallylic alcohols were reacted smoothly with sodium azide in the presence of p-toluenesulfonic acid (p-TsOH) to form synthetically viable triazolylacetates in good to high yields. Additionally, the nitroallylic acetates
Control of the Organocatalytic Enantioselective α-Alkylation of Vinylogous Carbonyl Enolates for the Synthesis of Tetrahydropyran Derivatives and Beyond
The organocatalytic α-alkylation of vinylogous carbonyl compounds to hydroxynitroolefins for the synthesis of hemiacetals was realized with excellent enantioselectivities and in high yields. High diastereoselectivity (up to >20:1) has been accomplished with the addition of Et3N. The α- and γ-alkylation of vinylogous ketone against nitroolefins displayed high but opposite facial selectivities. Transformation
以优异的对映选择性和高产率实现了用于合成半缩醛的乙烯基羰基化合物的有机催化 α-烷基化反应生成羟基硝基烯烃。通过添加 Et 3 N实现了高非对映选择性(高达 >20:1)。乙烯基酮对硝基烯烃的 α-和 γ-烷基化显示出高但相反的表面选择性。已证明半缩醛产物转化为其他多环化合物,包括euroticin B 类似物。
Strategic applications of Baylis–Hillman adducts to general syntheses of 3-nitroazetidines
作者:Ankita Rai、Lal Dhar S. Yadav
DOI:10.1039/c1ob06274c
日期:——
A novel one-pothighly diastereoselective synthesis of substituted 3-nitroazetidines via an anionic domino process is described. The synthesis involves a high yielding annulation of Baylis–Hillman alcohols and their aldehydes with either N-aryl/tosylphosphoramidates or N-aryl/tosylphosphoramidates in combination with a task-specificionicliquid [bmim][X–Y] to afford the corresponding 1,2,3-tri- and
A new application of Baylis–Hillman alcohols to a diastereoselective synthesis of 3-nitrothietanes
作者:Ankita Rai、Lal Dhar S. Yadav
DOI:10.1016/j.tet.2012.01.062
日期:2012.3
Three key reactions, the generation of a nucleophile, an thia-Michael addition and an intramolecular cyclisation, were used to achieve an efficient one-pot diastereoseletive synthesis of 3-nitrothietanes. Thus, Baylis–Hillman alcohols and their aldehydes were reacted with either O,O-diethyl hydrogen phosphorodithioate or O,O-diethyl hydrogen phosphorodithioate in combination with a task-specific ionic
Construction of Diverse Pyrrolidine-Based Skeletons through the Ag-Catalyzed Stereoselective Addition–Elimination Reaction of Azomethine Ylides with Nitroallyl Acetates
efficiently promotes the addition–elimination reaction, setting vicinal chiral stereocenters featuring a tetrasubstitutedcarbon with excellent enantio- and diastereoselectivity while leaving the versatile nitroolefin moiety. The broad substrate scope of this reaction and the transformability of the resulting nitroolefin, imine, and ester moieties allow for the construction of diverse pyrrolidine-based fused
由于支架多样性对生物筛选具有显着影响,因此高效、便捷地构建骨架多样化的化合物集合是药物发现的基本需求。在这方面,我们在此报告了吡咯啉酯与乙酸硝基烯丙酯的不对称串联共轭加成-消除反应及其在构建各种类型的稠合或螺环吡咯烷中的应用。 AgOAc/( R , Sp )-ThioClickFerrophos (TCF) 催化剂可有效促进加成-消除反应,设置邻位手性立体中心,其特征是具有优异对映体和非对映选择性的四取代碳,同时留下多功能硝基烯烃部分。该反应的广泛底物范围和所得硝基烯烃、亚胺和酯部分的可转化性允许通过各种分子内环化过程以光学活性形式构建多种基于吡咯烷的稠合或螺双环骨架。