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.
Cyclopropanation of alkenes with metallocarbenes generated from monocarbonyl iodonium ylides
作者:Tristan Chidley、Graham K. Murphy
DOI:10.1039/c8ob02636j
日期:——
Reacting Wittigreagents and the hypervalent iodine reagent iodosotoluene, in the presence of 10 mol% Cu(tfacac)2 and 5 equiv. of alkene, results in a novel cyclopropanation reaction. The reagent combination is believed to generate a transient monocarbonyliodoniumylide (MCIY) in situ, which can be intercepted by the copper catalyst to give a metallocarbene. Both ester and ketone derived phosphoranes
Semi‐Rationally Designed Short Peptides Self‐Assemble and Bind Hemin to Promote Cyclopropanation
作者:Oleksii Zozulia、Ivan V. Korendovych
DOI:10.1002/anie.201916712
日期:2020.5.18
amyloid assemblies can impart a substantial degree of enantioselectivity without the need for extensive optimization; 3. The ease of peptidepreparation allows for straightforward incorporation of unnatural aminoacids and preparation of peptides made of D-amino acids with complete reversal of enantioselectivity.
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。
Highly <i>cis</i>-Selective Cyclopropanations with Ethyl Diazoacetate Using a Novel Rh(I) Catalyst with a Chelating N-Heterocyclic Iminocarbene Ligand
A structurally characterized Rh(I) iminocarbene complex (N,C)Rh(CO)Cl is activated with AgOTf to act as a highly cis-selective catalyst for the cyclopropanation of substituted styrenes and other alkenes with ethyldiazoacetate (11 examples, 10−99% yield, up to >99% cis-selectivity).