Radical Cation Cyclopropanations via Chromium Photooxidative Catalysis
作者:Francisco J. Sarabia、Eric M. Ferreira
DOI:10.1021/acs.orglett.7b01095
日期:2017.6.2
The chromium photocatalyzed cyclopropanation of diazo reagents with electron-rich alkenes is described. The transformation occurs under mild conditions and features specific distinctions from traditional diazo-based cyclopropanations (e.g., avoiding β-hydride elimination, chemoselectivity considerations, etc.). The reaction appears to work most effectively using chromium catalysis, and a number of
Organoselenium-Catalyzed Asymmetric Cyclopropanations of (<i>E</i>)-Chalcones
作者:Pei-Tung Cheng、Yu-Hsun Tseng、Rong-Jie Chein
DOI:10.1021/acs.orglett.1c03243
日期:2021.10.15
compounds were used to catalyze asymmetriccyclopropanation reactions; the selenonium ylide intermediates formed from these selenium-containing catalysts and benzyl bromide efficiently react with (E)-chalcones to give various cyclopropanes (27 examples) with excellent enantioselectivities of ≤99% ee and are the first examples of organoselenium-catalyzed asymmetriccyclopropanations.
我们报告了一类新的基于 ( S )-二苯基(四氢硒酚-2-基) 甲醇的手性四氢硒酚,其由 ( R )-3-(3-溴丙基)-2,2-二苯基环氧乙烷和硒化钠制备。这些手性四氢硒酚类化合物用于催化不对称环丙烷化反应;由这些含硒催化剂和苄基溴形成的硒叶立德中间体与 ( E )-查耳酮有效反应,得到各种环丙烷(27 个实例),具有≤99% ee 的优异对映选择性,是有机硒催化不对称环丙烷化的第一个实例。
Phosphoranylidenehydrazones as in situ sources of diazo compounds: a facile synthesis of aryl-substituted benzoylcyclopropanes
作者:Frank S. Guziec、Frederick A. Luzzio
DOI:10.1021/jo00162a033
日期:1983.7
GUZIEC, F. S. JR.;LUZZIO, F. A., J. ORG. CHEM., 1983, 48, N 14, 2434-2437