Substituent effects on the13C NMR spectra of ethylcis- andtrans-2-(p-substituted-phenyl)-1-cyclopanecarboxylates
作者:Yoshiaki Kusuyama、Kenjiro Tokami
DOI:10.1002/mrc.1260300415
日期:1992.4
13C NMR spectra were measured for a series of ethyl cis- and trans-2-(p-substituted - phenyl) - 1 - cyclopropanecarboxylates. The effects of the para substituents and the geometry on the chemical shifts are discussed.
addition of the very reactive metallacarbene intermediate in an early transition state to the substrate alkene is concerted but strongly asynchronous, with substantial cationic character on one alkene carbon in the neighborhood of the transition state. Evidence from isotope effects and Hammett studies supports the nature of the transition state. Formation of a metallacyclobutaneintermediate by a [2+2] addition
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。
Asymmetric Inter- and Intramolecular Cyclopropanation Reactions Catalyzed by a Reusable Macroporous-Polymer-Supported Chiral Ruthenium(II)/Phenyloxazoline Complex
Along came poly: A novel macroporous polymer‐supported chiral RuII/pheox catalyst (1, see SEM image) afforded excellent reactivity and enantioselectivity in inter‐ and intramolecular cyclopropanation reactions with a broad range of substrates. The catalyst showed no leaching and could be reused up to 11 times, even after storage.
随之而来的是聚:一种新型的大孔聚合物负载的手性Ru II / pheox催化剂(1,参见SEM图片)在与多种底物的分子间和分子内环丙烷化反应中具有出色的反应性和对映选择性。该催化剂没有浸出,即使在储存后也可以重复使用多达11次。
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%.