<i>meta</i> C–H Arylation of Electron-Rich Arenes: Reversing the Conventional Site Selectivity
作者:Luo-Yan Liu、Jennifer X. Qiao、Kap-Sun Yeung、William R. Ewing、Jin-Quan Yu
DOI:10.1021/jacs.9b07887
日期:2019.9.18
report the first catalytic system that effectively performs meta C-Harylation of a variety of alkoxy aromatics including 2,3-dihydrobenzofuran and chromane with exclusive meta site-selectivity, thus reversing the conventional site selectivity governed by native electroniceffects. The identification of an effective ligand and modified norbornene (NBE-CO2Me), as well as taking advantage of the statistics
There is an increasing demand for facile delivery of silyl groups onto organic bioactive molecules. One of the common methods of silylation via a transition-metal-catalyzed coupling reaction employs hydrosilane, disilane, and silylborane as major silicon sources. However, the labile nature of the reagents or harsh reaction conditions sometimes render them inadequate for the purpose. Thus, a more versatile
Structurally diverse arylchlorides were silylated with sodium silylsilanolate reagents in the presence of a Ni(cod)2 catalyst complexed with a phosphine ligand; PMe2Ph for electron-rich substrates, and PCy2Ph for electron-deficient ones. The mild reaction conditions allowed the silylation of various arylchlorides including functionalised drug molecules.
Protodesilylation of Arylsilanes by Visible-Light Photocatalysis
作者:Jan H. Kuhlmann、Mustafa Uygur、Olga García Mancheño
DOI:10.1021/acs.orglett.2c00288
日期:2022.3.4
The first visible-light-mediated photocatalytic, metal- and base-free protodesilylation of arylsilanes is presented. The C(sp2)–Si bond cleavage process is catalyzed by a 5 mol % loading of a commercially available acridinium salt upon blue-light irradiation. Two simple approaches have been identified employing either aerobic or hydrogen atom transfer cocatalytic conditions, which enable the efficient
starting from trimethylsilyl‐substituted arenes is presented. By design of experiments, highly efficient and mild conditions were identified for a wide range of substrates. A functional group stability test and the synthesis of an important 3‐iodobenzylguanidine radiotracer illustrate the scope of this process.