Role of N, N’-Diboryl-4,4′-bipyridinylidene in the Transition-Metal-Free Borylation of Aryl Halides and Direct C-H Arylation of Unactivated Benzene was written by Waghamare, Akash B.;Raut, Ravindra K.;Patel, Niranjan;Majumdar, Moumita. And the article was included in European Journal of Inorganic Chemistry in 2022.COA of Formula: C12H16BBrO2 This article mentions the following:
N,N’-Diboryl-4,4′-bipyridinylidene (BBiPy) was utilized in sub-stoichiometric amounts along with anionic base as one electron donor species for both transition metal-free borylation of aryl halides and arene C-H functionalization with aryl iodides for biaryl syntheses. Reaction between BBiPy and potassium tert-butoxide or methoxide led to the formation of 4,4′-bipyridine radical anion (BiPy·–) with the release of an electron. The BiPy·- was structurally characterized. The single electron released was transferred to aryl halides generating aryl radicals, which then react with diboron in the presence of methoxide to form aryl boronate and with unactivated benzene in the presence of tert-butoxide to form biaryls. Substrate scopes studies showed that aryl iodides and bromides undergo borylation (1B-12B), while only aryl iodides undergo C-C bond formation with arene C-H (1C-8C) through radical chain reaction. Mechanisms for C-B and C-C bond formation have been proposed based on the exptl. findings. In the experiment, the researchers used many compounds, for example, 2-(4-Bromophenyl)-4,4,5,5-tetramethyl-1,3,2-dioxaborolane (cas: 68716-49-4COA of Formula: C12H16BBrO2).
2-(4-Bromophenyl)-4,4,5,5-tetramethyl-1,3,2-dioxaborolane (cas: 68716-49-4) belongs to alcohols. Similar to water, an alcohol can be pictured as having an sp3 hybridized tetrahedral oxygen atom with nonbonding pairs of electrons occupying two of the four sp3 hybrid orbitals. Secondary alcohols are easily oxidized without breaking carbon-carbon bonds only as far as the ketone stage. No further oxidation is seen except under very stringent conditions.COA of Formula: C12H16BBrO2
Referemce:
Alcohol – Wikipedia,
Alcohols – Chemistry LibreTexts