Catalyst-Controlled Regiodivergent C–H Arylation Site of Fluorinated 2‑Arylpyridine Derivatives: Application to Luminescent Iridium(III) Complexes

Regiodivergent
C–H bond arylation of fluorinated 2-arylpyridines
and 2-arylquinolines has been developed. The use of Pd catalyst allows
functionalization of the C–H bond of the aryl flanked by two
fluorine atoms (most acidic position), while using Ru catalyst, the
arylation takes place on the aryl unit at the ortho position of the heterocycle. Both reaction conditions exhibit
a good functional group tolerance. The synthetically useful selectivity
observed with Pd catalyst was applied to design C^N ligands for the
preparation of luminescent cationic iridium­(III) complexes. The influence
of the incorporated aryl group onto the fluorinated phenyl unit and
the fluorine position patterns on the photophysical properties is
described.

本工作开发了氟化2-芳基吡啶（2-arylpyridines）与2-芳基喹啉（2-arylquinolines）的区域发散型C-H键芳基化反应。采用钯（Pd）催化剂时，可实现双氟取代芳环（酸性最强位点）的C-H键官能化；而采用钌（Ru）催化剂时，芳基化反应则发生在杂环邻位的芳环单元上。两种反应体系均表现出优异的官能团耐受性。基于钯催化剂所展现出的合成实用型区域选择性，我们设计了C^N配体，用于制备发光阳离子铱(III)配合物。本文还探讨了引入氟化苯环单元的芳基取代基，以及氟原子取代位置模式对配合物光物理性质的影响。