Iminyl Radical-Mediated Controlled Hydroxyalkylation of Remote C(<i>sp</i>
<sup>3</sup>
)-H Bond via Tandem 1,5-HAT and Difunctionalization of Aryl Alkenes
A visible‐lightmediated γ‐hydroxyalkylation of ketones via C(sp3)‐H functionalization has been developed under redox neutral conditions. This protocol relies on the iminyl radical‐triggered 1,5‐HAT followed by oxyalkylation of alkenes, wherein C−C and C−O bonds were constructed in one step. This three‐component reaction features mild conditions, wide substrate scope and excellent functional group
Dual-Stereocontrol Asymmetric Cobalt-Catalyzed Hydroboration of Sterically Hindered Styrenes
作者:Heyi Zhang、Zhan Lu
DOI:10.1021/acscatal.6b02278
日期:2016.10.7
An oxazoline aminoisopropylpyridine (OAP) was designed and synthesized for cobalt-catalyzed asymmetric hydroboration of stericallyhindered styrenes. A unique dual-stereocontrol phenomenon was observed using a rigid OIP·CoCl2 complex or a flexible OAP with CoCl2 as precatalysts, respectively. The reaction could be easily carried out on a gram scale to afford chiral alkylboronic esters which could be
single-electron transfer of α,α,α-trifluoromethyl arenes in the presence of lithium salt to give α,α-difluoroalkylarenes. The C−F bond reduction was realized by lithium iodide and triethylamine, two common feedstock reagents. Computational studies indicated that the lithium-assisted defluorination and the single-electron reduction occurred concertedly. We call this phenomenon fluoride-coupled electron transfer