Directed <i>ortho</i> C–H borylation catalyzed using Cp*Rh(<scp>iii</scp>)–NHC complexes
作者:Jompol Thongpaen、Thibault E. Schmid、Loic Toupet、Vincent Dorcet、Marc Mauduit、Olivier Baslé
DOI:10.1039/c8cc03144d
日期:——
bidentate NHC-carboxylate ligands were efficiently synthesized and fully characterized including solid-state structures. These unprecedented rhodium(III) complexes demonstrated high selectivity in pyridine-directed ortho-C–H borylation of arenes under mild conditions.
Supported phosphine-Rh systems, prepared in situ from silica-supported bridgehead monophosphines and [Rh(OH)(cod)]2, have enabled ortho-selective C-H borylation for a range of arenes containing nitrogen-based directing groups. The regioselectivity was excellent with various N-directing groups, including saturated and unsaturated N-heterocycles, tert-aminoalkyl groups, and iminetype C-N double bonds. The reaction showed significant tolerance toward steric repulsion around the reacting C-H bond. This Rh catalysis complements the Jr-catalyzed orthoborylation, which is effective for arenes with oxygen-based directing groups.
Remarkably Efficient Iridium Catalysts for Directed C(sp<sup>2</sup>)–H and C(sp<sup>3</sup>)–H Borylation of Diverse Classes of Substrates
aliphatic substrates for selective C(sp3)–H bond borylations. Heterocyclic molecules are selectively borylated using the inherently elevated reactivity of the C–H bonds. A number of late-stage C–H functionalization have been described using the same catalysts. Furthermore, we show that one of the catalysts could be used even in open air for the C(sp2)–H and C(sp3)–Hborylations enabling the method more general
Photo-Induced <i>ortho</i>-C–H Borylation of Arenes through In Situ Generation of Rhodium(II) Ate Complexes
作者:Jin Tanaka、Yuki Nagashima、Antônio Junio Araujo Dias、Ken Tanaka
DOI:10.1021/jacs.1c05859
日期:2021.8.4
Photoinduced in situ “oxidation” of half-sandwich metal complexes to “high-valent” cationic metal complexes has been used to accelerate catalytic reactions. Here, we report the unprecedented photoinduced in situ “reduction” of half-sandwich metal [Rh(III)] complexes to “low-valent” anionic metal [Rh(II)] ate complexes, which facilitate ligand exchange with electron-deficient elements (diboron). This