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。
Hydriodic Acid-Mediated Cyclization of α-Substituted Secondary 2-Ethenylbenzamides: Synthesis of 2-Substituted 2,3-Dihydro-3,3-dimethyl-1H-isoindol-1-ones and 3,3-Disubstituted (E)-1-(Arylimino)-1,3-dihydroisobenzofurans
for the preparation of 2‐substituted 2,3‐dihydro‐3,3‐dimethyl‐1H‐isoindol‐1‐ones 3 and 3,3‐disubstituted (E)‐1‐(arylimino)‐1,3‐dihydroisobenzofurans 6 has been developed. Thus, treatment of N‐alkyl(or aryl)‐2‐(1‐methylethen‐1‐yl)benzamides 2 with concentrated hydriodic acid (HI) in MeCN at room temperature afforded 3. Similar treatment of N‐aryl‐2‐(1‐phenylethen‐1‐yl)benzamide 5 with concentrated HI
A visible light‐induced photocatalytic radical addition/cyclization reaction of o‐vinyl‐N‐alkoxybenzamides has been accomplished for efficient synthesis of diversely functionalized CF3‐containing iminoisobenzofurans. This external oxidant‐free and mild protocol features ready availability of starting materials, excellent regioselectivity, good substrate scope and functional group tolerance.
A new and simple method for the preparation of 3,3-disubstituted isoindolin-1-ones from α-substituted 2-bromostyrenes is described. Construction of the isoindolin-1-one skeleton was accomplished by treating α-substituted secondary 2-vinylbenzamides, easily obtainable from the reaction of α-substituted 2-lithiostyrenes with isocyanates, with iodine to afford 3-substituted 3-iodomethylisoindolin-1-ones.