synthesis of new core-Au/shell-CeO2 nanoparticles (Au@CeO2) using a redox-coprecipitation method, where the Au nanoparticles and the nanoporous shell of CeO2 are simultaneously formed in one step. The Au@CeO2catalyst enables the highly selective semihydrogenation of various alkynes at ambient temperature under additive-free conditions. The core-shellstructure plays a crucial role in providing the excellent
我们报告了一种使用氧化还原共沉淀法轻松合成新的核-Au/壳-CeO2 纳米颗粒(Au@ ),其中 Au 纳米颗粒和 的纳米多孔壳在一个步骤中同时形成。Au@ 催化剂能够在无添加剂的条件下在环境温度下实现各种炔烃的高选择性半氢化。核-壳结构通过最大化核-Au 和壳- 之间的界面位点,以异裂方式选择性解离 H2,从而为烯烃提供优异的选择性。
Copper-catalyzed enantioselective alkene carboetherification for the synthesis of saturated six-membered cyclic ethers
作者:Ilyas A. Berhane、Ameya S. Burde、Jonathan J. Kennedy-Ellis、Eva Zurek、Sherry R. Chemler
DOI:10.1039/d1cc03515k
日期:——
The enantioselective copper-catalyzed oxidative coupling of alkenols with styrenes for the construction of dihydropyrans, isochromans, pyrans and morpholines is reported. A concise formal synthesis of a σ1 receptor ligand using this alkene carboetherification methodology was demonstrated. Ligand, solvent and base all impact reaction efficiency. DFT transition state calculations are presented.
We have designed a convergent path for the synthesis of the key fragments (C1–C7 and C6–C22) of phostriecin. The approach not only provides ready access to several biologically active molecules, such as 5‐hydroxygoniothalamin, 5‐acetoxygoniothalamin, and their analogues, but also (S)‐5‐[(S)‐1‐hydroxyallyl]furan‐2(5H)‐one derivatives with cross metathesis as the key reaction.
Palladium catalyzed coupling of organostannanes with vinyl epoxides
作者:David R. Tueting、Antonio M. Echavarren、J.K. Stille
DOI:10.1016/0040-4020(89)80010-9
日期:1989.1
The coupling reaction of organotin reagents with vinyl epoxides, catalyzed by palladium, takes place at ambient temperatures, regioselectively, giving predominately the 1,4-addition product. Both aryl- and vinylstannanes undergo coupling in high yields, while acetylenic, allylic and benzylic tin reagents either give low yields or fail to couple. Although the double bond geometry in the vinylstannane
Double Ring-Closing Metathesis Reaction of Nitrogen-Containing Tetraenes: Efficient Construction of Bicyclic Alkaloid Skeletons and Synthetic Application to Four Stereoisomers of Lupinine and Their Derivatives
作者:Shengming Ma、Bukuo Ni
DOI:10.1002/chem.200305581
日期:2004.7.5
The doublering-closingmetathesisreaction of nitrogen-containingtetraenes was studied. The selectivity of the fused/dumbbell-type products can be controlled by the electronic/steric effects of the substituents attached to the C[double bond]C bonds and the s-cis/s-trans conformational ratios of the substrates. This methodology has also been successfully applied to the enantioselective synthesis of