A palladium-catalyzed domino process for the quick assembly of tricyclic-fused heterocycles starting from aryl iodides and functionalized isocyanides containing a disubstituted terminal alkene has been developed. The process is triggered by intermolecular isocyanide insertion, followed by Heck-type carbopalladation of the intramolecular alkene moiety and subsequent C(sp2)–H activation. Moreover, an
The Synthetic Intermediate of Pyridoxine. II. The Thermal Cyclization of Ethyl α-Isocyanopropionate to 5-Ethoxy-4-methyloxazole
作者:Itsutoshi Maeda、Kazushi Togo、Ryonosuke Yoshida
DOI:10.1246/bcsj.44.1407
日期:1971.5
product, II, was 20%; unreacted I (30%), ethyl α-cyanopropionate(20%), and dimer of I (5%) were also obtained. The α-hydrogen of ethyl α-isocyanosuccinate (X) can be more easily removed than that of I, so X may be expected to be more readily converted to 5-ethoxy-4-ethoxycarbonylmethyloxazole (XI), which is also an intermediate of pyridoxine. The yield of XI from X did not exceed 30% because of the
α-异氰基丙酸乙酯 (I) 热环化生成 5-乙氧基-4-甲基恶唑 (II) 作为合成吡哆醇的中间体。也进行了几种新的α-异氰基羧酸烷基酯与相应的5-烷氧基-4-取代的恶唑的类似反应。研究了I的热环化反应产物。180℃环化5小时,主产物II的最大收率为20%;还得到了未反应的 I (30%)、α-氰基丙酸乙酯 (20%) 和 I 的二聚体 (5%)。α-异氰基琥珀酸乙酯 (X) 的 α-氢比 I 更容易去除,因此可以预期 X 更容易转化为 5-乙氧基-4-乙氧基羰基甲基恶唑 (XI),它也是吡哆醇。
The Synthetic Intermediate of Pyridoxine. III. The Simple Synthesis of Ethyl<i>N</i>-Ethoxalylalaninate and Ethyl<i>N</i>-Formylalaninate
作者:Itsutoshi Maeda、Soichiro Asai、Hideshi Miyayashiki、Ryonosuke Yoshida
DOI:10.1246/bcsj.45.1917
日期:1972.6
Intramolecular Imidoylative Heck Reaction: Synthesis of Cyclic Ketoimines from Functionalized Isocyanide
作者:Jian Wang、Shi Tang、Qiang Zhu
DOI:10.1021/acs.orglett.6b01174
日期:2016.7.1
Efficient access to five- to seven-membered cyclic ketoimines, through palladium-catalyzed intramolecular imidoylative Heckreaction of alkene-containing isocyanides, has been developed. Consecutive isocyanide and alkene insertion into aryl or alkyl Pd(II) intermediates takes place in this process. No byproduct derived from monoinsertion or reversed sequence is detected.