Electrochemical oxidative radical cascade cyclization of olefinic amides and thiophenols towards the synthesis of sulfurated benzoxazines, oxazolines and iminoisobenzofurans
containing N and O are important structures in pharmaceuticals, agrochemicals and functional molecules. The synthesis of these compounds usually requires complex substrates and harsh reaction conditions. Herein, we introduce a mild and efficient electrochemical oxidative strategy to construct benzoxazines, oxazolines and iminoisobenzofurans without the requirement of a transition-metal catalyst and an
含 N 和 O 的杂环是药物、农用化学品和功能分子中的重要结构。这些化合物的合成通常需要复杂的底物和苛刻的反应条件。在此,我们引入了一种温和有效的电化学氧化策略来构建苯并恶嗪、恶唑啉和亚氨基异苯并呋喃,而无需过渡金属催化剂和外部氧化剂。在一个简单的未分开的细胞中,各种烯酰胺和苯硫酚/二硒化物反应生成 69 个硫醇化和硒化杂环的例子,产率高达 83%。此外,这种自由基级联反应为一步构建 C-S/C-Se 和 C-O 键提供了一种简便的方法。
Efficient synthesis of SCF<sub>3</sub>-substituted tryptanthrins by a radical tandem cyclization
作者:Jincheng Guo、Yanan Hao、Gang Li、Ziwen Wang、Yuxiu Liu、Yongqiang Li、Qingmin Wang
DOI:10.1039/d0ob00233j
日期:——
we report a new, efficient and atom-economical strategy for the synthesis of SCF3-substituted tryptanthrin derivatives. These previously unreported derivatives were obtained by means of a radical tandem cyclization. The reaction was triggered by addition of a SCF3 radical to a carbon-carbon double bond and involved the formation of a C(sp3)-SCF3 bond, a C(sp2)-C bond, and a C(sp2)-N bond. This method
A copper-catalyzedC(sp3)–H bondfunctionalization of simple alkanes with olefinic amides was developed for the efficient synthesis of important benzoxazine derivatives. It involves new C-C and C-O bondformation in one step via radical cascade process.
A new, efficient, and practical radical cyclization of olefinic amides with ketones through α-C(sp3)–H functionalization in the presence of tert-butyl peroxybenzoate (TBPB) is described for the first time. This protocol assembles a wide range of pivotal and useful benzoxazines in good to excellent yields under mild, catalyst-free, ligand-free, and base-free conditions with wide functional group tolerance
Treatment of Olefinic Amides with NBS in Water: Synthesis of Monobromo- and Multibromobenzoxazines
作者:Xu Zhang、Wen-Bin Cao、Xiao-Ping Xu、Shun-Jun Ji
DOI:10.1055/s-0037-1610724
日期:2019.10
Abstract Treatment of olefinic amides with N-bromosuccinimide (NBS) in water is reported. Monobromobenzoxazines were mainly formed at room temperature, while at 80 °C multibromobenzoxazines were preferentially generated. Mechanism studies showed that the reaction might proceed via a cascade of electrophilic addition at the C=C bond followed by electrophilic substitution at the aromatic ring. No additives