Organoboron compounds are highly useful in various fields such as synthetic organic chemistry, pharmaceutical chemistry, and materials chemistry as well as analytical chemistry. However, there have been limited reports dealing with their electrochemical properties and reactions to date.
1-3) Quite recently, we found marked negative shifts of the oxidation potentials of alkyl and aryboronic acids and their esters in the presence of fluoride ions compared with those in the absence of fluoride ions.
4-8) It was also clarified that negative shift was derived from the formation of negatively charged boron-ate complex with fluoride ions. In this talk, we focus on our new finding of the β-effect of organoboronic acid esters having a heteroatom or unsaturated bond at their α-position, which is more pronounced compared with that of the corresponding organosilicon compounds.
5,6,8) Anodic radical coupling of organotrifluoroborates
7) and substitutions of organoboronic acid esters with oxygen nucleophiles have been achieved.
4-8) Thus, we have shown that boryl groups work as electroauxiliaries like silyl groups.
References:
1) J. Yoshida, T. Nokami, and S. Suga, in Organic Electrochemistry, 5th Ed., O. Hammerich and B. Speiser (Eds.), CRC Press, FL, (2015), Ch. 35
2) H. Scha¨fer and D. Koch, Angew. Chem. Int. Ed. 11, 48 (1972).
3) L. A. Shundrin, V. V. Bardin, H.-J. Frohn, Z. Anorg. Allg. Chem. 630, 1253 (2004).
4) J. Suzuki, N. Shida, S. Inagi, and T. Fuchigami, Electroanalysis, 28, 2797 (2016).
5) M. Tanigawa, Y. Kuriyama, S. Inagi, and T. Fuchigami, Elecrochim. Acta, 199, 314 (2016).
6) K. Ohtsuka, S. Inagi, and T. Fuchigami, ChemElectroChem, in press, DOI:10.1002/celc.201600519.
7) J. Suzuki, M. Tanigawa, S. Inagi, and T. Fuchigami, ChemElectroChem, in press, DOI: 10.1002/celc.201600451.
8) K. Ohtsuka, S. Inagi, and T. Fuchigami, J. Electrochem. Soc. in press, DOI: 10.1149/2.0561702jes.
