Reprint of: Impact of the corrin framework of vitamin B12 on the electrochemical carbon-skeleton rearrangement in comparison to an imine/oxime planar ligand; tuning selectivity in 1,2-migration of a functional group by controlling electrolysis potential

Keishiro Tahara; Ling Pan; Ryoko Yamaguchi; Hisashi Shimakoshi; Masaaki Abe; Yoshio Hisaeda

doi:10.1016/j.jinorgbio.2017.09.021

Reprint of: Impact of the corrin framework of vitamin B₁₂ on the electrochemical carbon-skeleton rearrangement in comparison to an imine/oxime planar ligand; tuning selectivity in 1,2-migration of a functional group by controlling electrolysis potential

J Inorg Biochem. 2017 Dec:177:438-443. doi: 10.1016/j.jinorgbio.2017.09.021. Epub 2017 Sep 29.

Authors

Keishiro Tahara¹, Ling Pan², Ryoko Yamaguchi³, Hisashi Shimakoshi³, Masaaki Abe⁴, Yoshio Hisaeda⁵

Affiliations

¹ Department of Chemistry and Biochemistry, Graduate School of Engineering, Kyushu University, Fukuoka 819-0395, Japan; Department of Material Science, Graduate School of Material Science, University of Hyogo, 3-2-1, Kouto, Kamigori, Ako 6781297, Japan.
² Department of Chemistry and Biochemistry, Graduate School of Engineering, Kyushu University, Fukuoka 819-0395, Japan; Department of Chemistry, Northeast Normal University, Changchun 130024, PR China.
³ Department of Chemistry and Biochemistry, Graduate School of Engineering, Kyushu University, Fukuoka 819-0395, Japan.
⁴ Department of Material Science, Graduate School of Material Science, University of Hyogo, 3-2-1, Kouto, Kamigori, Ako 6781297, Japan.
⁵ Department of Chemistry and Biochemistry, Graduate School of Engineering, Kyushu University, Fukuoka 819-0395, Japan; Center for Molecular Systems (CMS), Kyushu University, Fukuoka 819-0395, Japan. Electronic address: yhisatcm@mail.cstm.kyushu-u.ac.jp.

PMID: 29046224
DOI: 10.1016/j.jinorgbio.2017.09.021

Abstract

Among the coenzyme B₁₂-dependent enzymes, methylmalonyl-CoA mutase (MMCM) catalyzes the carbon-skeleton rearrangement reaction between R-methylmalonyl-CoA and succinyl-CoA. Diethyl 2-bromomethyl-2-phenylmalonate, an alkyl bromide substrate having two different migrating groups (phenyl and carboxylic ester groups) on the β-carbon, was applied to the electrolysis mediated by a hydrophobic vitamin B₁₂ model complex, heptamethyl cobyrinate perchlorate in this study. The electrolysis of the substrate at -1.0V vs. Ag-AgCl by light irradiation afforded the simple reduced product (diethyl 2-methyl-2-phenylmalonate) and the phenyl migrated product (diethyl 2-benzyl-2-phenylmalonate), as well as the electrolysis of the substrate at -1.5V vs. Ag-AgCl in the dark. The electrolysis of the substrate at -2.0V vs. Ag-AgCl afforded the carboxylic ester migrated product (diethyl phenylsuccinate) as the major product. The selectivity for the migrating group was successfully tuned by controlling the electrolysis potential. We clarified that the cathodic chemistry of the Co(III) alkylated heptamethyl cobyrinate is critical for the selectivity of the migrating group through mechanistic investigations and comparisons to the simple vitamin B₁₂ model complex, an imine/oxime-type cobalt complex.

Keywords: 1,2-Migration; Carbon-skeleton rearrangement; Electrolysis; Heptamethyl cobyrinate; Vitamin B(12).