19256-47-4

Upstream product

• 937-14-4 3-chloro-benzenecarboperoxoic acid 
• 625-99-0 3-iodochlorobenzene 
• 811-98-3 d⁽⁴⁾-methanol 
• 108-90-7 chlorobenzene 

Relevant academic research and scientific papers

Mechanism of Ni-catalyzed oxidations of unactivated C(sp3)-H Bonds

The Ni-catalyzed oxidation of unactivated alkanes, including the oxidation of polyethylenes, by meta-chloroperbenzoic acid (mCPBA) occur with high turnover numbers under mild conditions, but the mechanism of such transformations has been a subject of debate. Putative, high-valent nickel-oxo or nickel-oxyl intermediates have been proposed to cleave the C-H bond, but several studies on such complexes have not provided strong evidence to support such reactivity toward unactivated C(sp3)-H bonds. We report mechanistic investigations of Ni-catalyzed oxidations of unactivated C-H bonds by mCPBA. The lack of an effect of ligands, the formation of carbon-centered radicals with long lifetimes, and the decomposition of mCPBA in the presence of Ni complexes suggest that the reaction occurs through free alkyl radicals. Selectivity on model substrates and deuterium-labeling experiments imply that the m-chlorobenzoyloxy radical derived from mCPBA cleaves C-H bonds in the alkane to form an alkyl radical, which subsequently reacts with mCPBA to afford the alcohol product and regenerate the aroyloxy radical. This free-radical chain mechanism shows that Ni does not cleave the C(sp3)-H bonds as previously proposed; rather, it catalyzes the decomposition of mCPBA to form the aroyloxy radical.

Metal-Free sp2-C-H Borylation as a Common Reactivity Pattern of Frustrated 2-Aminophenylboranes

C-H borylation is a powerful and atom-efficient method for converting affordable and abundant chemicals into versatile organic reagents used in the production of fine chemicals and functional materials. Herein we report a facile C-H borylation of aromatic and olefinic C-H bonds with 2-aminophenylboranes. Computational and experimental studies reveal that the metal-free C-H insertion proceeds via a frustrated Lewis pair mechanism involving heterolytic splitting of the C-H bond by cooperative action of the amine and boryl groups. The adapted geometry of the reactive B and N centers results in an unprecedentently low kinetic barrier for both insertion into the sp2-C-H bond and intramolecular protonation of the sp2-C-B bond in 2-ammoniophenyl(aryl)- or -(alkenyl)borates. This common reactivity pattern serves as a platform for various catalytic reactions such as C-H borylation and hydrogenation of alkynes. In particular, we demonstrate that simple 2-aminopyridinium salts efficiently catalyze the C-H borylation of hetarenes with catecholborane. This reaction is presumably mediated by a borenium species isoelectronic to 2-aminophenylboranes.

Copper-mediated difluoromethylation of aryl and vinyl iodides

Selectively fluorinated molecules are important as materials, pharmaceuticals, and agrochemicals, but their synthesis by simple, mild, laboratory methods is challenging. We report a straightforward method for the cross-coupling of aryl and vinyl iodides with a difluoromethyl group generated from readily available reagents to form difluoromethylarenes and difluoromethyl-substituted alkenes. The reaction of electron-neutral, electron-rich, and sterically hindered aryl and vinyl iodides with the combination of CuI, CsF and TMSCF2H leads to the formation of difluoromethyl-substituted products in high yield with good functional group compatibility. This transformation is surprising, in part, because of the prior observation of the instability of CuCF2H.