We reported a facile metal-free conversion of aryl halides to the corresponding boronic esters catalysed by an in situ formed donor–acceptor complex. A two-step one-pot method was also developed for site selective aromatic C–H bond borylation.
11 March 2025 in European Journal of Organic Chemistry
Carbon-heteroatom bond (especially for C-N bond) formation through nickel catalysis has seen significant development. Well-established Ni(0)/Ni(II) redox cycle and photoinduced Ni(I)/Ni(III) redox cycle have been the dominant mechanisms. We report a thermally driven Ni-catalyzed method for C-N bond formation between haloarenes and B2N4 reagents, yielding N,N-dialkylaniline derivatives in good to excellent yields with broad functional group tolerance under base-free conditions. The catalytic protocol is useful for base-sensitive structures and late-stage modifications of complex molecules. Detailed mechanistic studies and density functional theory (DFT) calculations indicate that a Ni(I)/Ni(III) redox cycle is preferred in the C-N coupling process, and B2N4 reagent serves both as a single electron transfer donor and a N,N-dialkylation source.
We have developed a novel electron-donor-acceptor (EDA) photocatalyst through DFT-guided design. This photocatalyst is formed in situ from isoquinoline, a diboron reagent, and a weak base, and can be effectively utilized for challenging reactions.