Cyclopropanation of Olefins with Diazo Compounds Catalyzed by a Dicopper-substituted Silicotungstate [γ-H<sub>2</sub>SiW<sub>10</sub>O<sub>36</sub>Cu<sub>2</sub>(μ-1,1-N<sub>3</sub>)<sub>2</sub>]<sup>4−</sup>
作者:Keigo Kamata、Toshihiro Kimura、Noritaka Mizuno
DOI:10.1246/cl.2010.702
日期:2010.7.5
silicotungstate (TBA) 4 -[γ-H 2 SiW 10 O 36 Cu II 2 (μ-1,1-N 3 ) 2 ] (I, TBA = tetra-n-butylammonium) could act as an efficient precatalyst for the chemoselective cylopropanation of olefins with diazo compounds. Various kinds of olefins were efficiently converted to the corresponding cyclopropane derivatives in good yields.
双铜取代的 γ-Keggin 硅钨酸盐 (TBA) 4 -[γ-H 2 SiW 10 O 36 Cu II 2 (μ-1,1-N 3 ) 2 ] (I, TBA = 四正丁基铵)作为烯烃与重氮化合物化学选择性环丙烷化的有效预催化剂。各种烯烃以良好的收率有效地转化为相应的环丙烷衍生物。
A general stereoselective method for the synthesis of cyclopropanecarboxylates. A new version of the homologous Horner–Wadsworth–Emmons reaction
作者:Henryk Krawczyk、Katarzyna Wąsek、Jacek Kędzia、Jakub Wojciechowski、Wojciech M. Wolf
DOI:10.1039/b712145h
日期:——
The synthesis of α-, β- and γ-substituted α-phosphono-γ-lactones was accomplished using different ring closure and ring homologation strategies. It was found that the lactones could be selectively transformed into the corresponding ethyl cyclopropanecarboxylates by treatment with sodium ethoxide in boiling THF. The reported reaction provides an attractive alternative to the classical homologous HornerâWadsworthâEmmons approach to the construction of cyclopropanes with electron-withdrawing functionalities.
Chiral bipyridine–copper(II) complex. Crystal structure and catalytic activity in asymmetric cyclopropanation
作者:Hoi-Lun Kwong、Wing-Sze Lee、Hung-Foon Ng、Wing-Hong Chiu、Wing-Tak Wong
DOI:10.1039/a706754b
日期:——
A chiral bipyridineâcopper(II) complex has been prepared and its crystal structure determined. The structure involves a CuN2Cl2 compressed tetrahedral stereochemistry. Chiral bipyridine complexes of copper-(I) and -(II) triflate are active catalysts for asymmetric cyclopropanation of alkenes with enantiomeric excesses up to 92%.
Highly enantioselective and cis-diastereoselective cyclopropanation of olefins catalyzed by ruthenium complexes of (iminophosphoranyl)ferrocenes
作者:Vo D.M. Hoang、Pattubala A.N. Reddy、Tae-Jeong Kim
DOI:10.1016/j.tetlet.2007.09.035
日期:2007.11
Chiral (iminophosphoranyl)ferrocenes (1 and 2) are highly efficient ligands to achieve high diastereoselectivity (up to 95/5 dr in favor of the cis-isomer) as well as enantioselectivity (up to 99% ee) in Ru-catalyzed asymmetric cyclopropanation of various olefins. Reversal in diastereoselectivity is found as a function of metal-to-ligand ratio in the reaction of styrene.
Chiral C2-symmetric bisferrocenyldiamines as ligands for transition metal catalyzed asymmetric cyclopropanation and aziridination
作者:Dong-Jei Cho、Sang-Jin Jeon、Hong-Seok Kim、Chan-Sik Cho、Sang-Chul Shim、Tae-Jeong Kim
DOI:10.1016/s0957-4166(99)00423-1
日期:1999.9
A new series of chiral C2-symmetric bisferrocenyldiimine 1 and bisferrocenyldiamines 2 and 3 proved to be efficient ligands for the copper(I)-catalyzed asymmetriccyclopropanation, cyclopropenation, and aziridination of alkenes and alkynes to give high diastereo- and enantioselectivity as well as high chemical yields. In some instances the enantiomeric excesses of cyclopropanated products are among