Anodic Oxidation of (Trimethylsilyl)methanes with π-Electron Substituents in the Presence of Nucleophiles
作者:Toshio Koizumi、Toshio Fuchigami、Tsutomu Nonaka
DOI:10.1246/bcsj.62.219
日期:1989.1
It was found that oxidation potentials of methanes with π-electron substituents were decreased by introduction of a trimethylsilyl group. The anodicoxidation of benzyl-, allyl-, aryl(or alkyl)thiomethyl-, and aryloxymethyl-substituted trimethylsilanes smoothly proceeded in the presence of nucleophiles, e.g. alcohols and carboxylic acids, to eliminate the trimethylsilyl groups giving the corresponding
Schiff base Mn(<scp>iii</scp>) and Co(<scp>ii</scp>) complexes coated on Co nanoparticles: an efficient and recyclable magnetic nanocatalyst for H<sub>2</sub>O<sub>2</sub> oxidation of sulfides to sulfoxides
immobilization of manganese and cobalt Schiff base-complexes on Co magnetite nanoparticles (MNP). The catalysts Co@SiO2[(EtO)3Si–L3]/M (M = Mn(III) and Co(II)) were synthesized using Co@SiO2 core–shell nanoparticles and amino-functionalized Co@SiO2. The Schiff base ligand Co@SiO2[(EtO)3Si–L3] was synthesized by reacting Co@SiO2 core–shell nanoparticles with 2-hydroxy 1-naphthaldehyde for the synthesis of Co@SiO2[(EtO)3Si–L3]/M
Total Synthesis of (−)-Scabronine G, an Inducer of Neurotrophic Factor Production
作者:Stephen P. Waters、Yuan Tian、Yue-Ming Li、Samuel J. Danishefsky
DOI:10.1021/ja055220x
日期:2005.10.1
The totalsynthesis of (-)-scabronine G has been achieved in a concise manner from the (-)-Wieland-Miescher ketone. Scabronine G and its more potent methyl ester (also prepared) display activity as nonpeptidyl inducers of nerve growth factor production.
(-)-scabronine G 的全合成已从 (-)-Wieland-Miescher 酮以简洁的方式实现。Scabronine G 及其更有效的甲酯(也已制备)显示出作为神经生长因子产生的非肽基诱导剂的活性。
Enantioselective total synthesis of taxol has been accomplished. Coupling reaction of the optically pure A-ring hydroxy aldehyde with the aromatic C-ring fragment followed by Lewis acid mediated eight-membered B-ring cyclization gave the desired ABC endo-tricarbocycle. The C-ring moiety of this product was reduced under Birch conditions to the cyclohexadiene derivative, which was oxygenated by singlet
完成了紫杉醇的对映选择性全合成。光学纯 A 环羟基醛与芳族 C 环片段的偶联反应,然后是路易斯酸介导的八元 B 环环化,得到所需的 ABC 内三碳环。该产物的 C 环部分在 Birch 条件下被还原为环己二烯衍生物,该衍生物被来自凸 β 面的单线态氧氧化,立体选择性地得到 C4β、C7β-二醇。为了引入C19-甲基,环丙基酮通过C-环烯丙醇的环丙烷化或氰基与C-环烯酮的共轭加成来制备。环丙烷环的还原裂解,然后将所得烯醇异构化为相应的酮,得到含有 C19-甲基的关键合成中间体。
Electrooxidative Inter- and Intramolecular Carbon−Carbon Bond Formation Using Organothio Groups as Electroauxiliaries
s having a carbon-carbon double bond in an appropriate position using Bu(4)NBF(4) as the supporting electrolyte leads to the effective cyclization and the introduction of the fluoride to one of the formal olefinic carbon. The present study demonstrates the effectiveness of organothiogroups as electroauxiliaries in electrooxidativeinter- and intramolecularcarbon-carbonbondformation.