Regioselective Palladium(II)-Catalyzed Synthesis of Five- or Seven-Membered Ring Lactones and Five-, Six- or Seven-Membered Ring Lactams by Cyclocarbonylation Methodology
作者:Bassam El Ali、Kazumi Okuro、Giuseppe Vasapollo、Howard Alper
DOI:10.1021/ja953403l
日期:1996.1.1
affording five- or seven-memberedring lactones (bicyclic, tricyclic, and pentacyclic) as the principal products, often in excellent yields. Use of 2-aminostyrenes as reactants and catalytic quantities of palladium acetate and tricyclohexylphosphine, affords five-membered ring lactams in high yield and selectivity. Bicyclic and tricyclic heterocycles containing six-membered ring lactams can be synthesized
A total synthesis of antipodal virantmycin was accomplished starting from p-aminobenzoic acid. Absolute stereochemistry of the natural one was shown to be 2S, 3R.
作者:Yulian Duan、Tao Wang、Qingxiao Xie、Xiaobo Yu、Weijie Guo、Jianhui Wang、Guiyan Liu
DOI:10.1039/c6dt03899a
日期:——
metathesis catalysts containing an N-heterocyclic carbene (NHC) and a carbonylgroup have been developed and their catalytic activities for olefin metathesis reactions were investigated. The X-ray structure of the [(H2IMes)(Cl)2Ru]C(H)CH2[p-F(C6H3)NC(CF3)(C(O)OCH2CH3)] complex shows that the carbonyl oxygen of the ester and the imine nitrogen are both coordinated to the Ru metal to give an octahedral
已开发出一系列含有N-杂环卡宾(NHC)和羰基的氮螯合钌卡宾复分解催化剂,并研究了它们对烯烃复分解反应的催化活性。[(H 2 IMes)(Cl)2 Ru] C(H)CH 2 [ p -F(C 6 H 3)NC(CF 3)(C(O)OCH 2 CH 3)]配合物表明,酯的羰基氧和亚胺氮都与Ru金属配位,得到八面体结构。测试了这些钌卡宾配合物对烯烃复分解反应的催化活性。一些带有吸电子基团的配合物具有较高的引发速率。这些复合物对于闭环复分解和交叉复分解均显示出优异的性能。
Synthetic studies on virantmycin. 1. Total synthesis of (±)-virantmycin and determination of its relative stereochemistry
a ring inversion occurs in their piperidine ring system and determined the relative stereochemistry by capturing each half-chair conformer as cyclic carbamates 26 and 27, respectively. Utilizing this protocol total syntheses of (±)-1 and its diastereomer (±)-2 have been accomplished and the relative stereochemistry of virantmycin has been established as shown in 1.