Hydrophobic vitamin B12. Part 12. Preparation, characterization and enantioselective alkylation of strapped hydrophobic vitamin B12

Yukito Murakami, Yoshio Hisaeda, Teruhisa Ohno, Hiroshi Kohno, Takuya Nishioka

Research output: Contribution to journalArticle

17 Citations (Scopus)

Abstract

Cyanocobalamin has been modified to afford a strapped hydrophobic vitamin B12 by introducing a 1,3-phenylenediacetyl moiety into the peripheral site of the corrin's B ring. The modified complex was characterized by various spectroscopic methods and cyclic voltammetry in comparison with the corresponding data for a simple hydrophobic vitamin B12 without a strapping moiety. The alkylation of hydrophobic vitamin B12 derivatives with racemic 3-bromo-2-methylpropionic esters at the β-axial site was carried out in methanol, and extents of the enantioselectivity were examined by 1H NMR spectroscopy. The strapped hydrophobic vitamin B12 and a simple hydrophobic vitamin B12 were found to react with (S)-3-bromo-2-methylpropionates more readily than the corresponding R-enantiomers; the highest S-selectivity (75% ee) was observed with the strapped hydrophobic vitamin B12. The 5-enantioselectivity was discussed from a stereochemical viewpoint based on the conformational search for the alkylated hydrophobic vitamin B12 by means of molecular mechanics and dynamics calculations.

Original languageEnglish
Pages (from-to)1175-1183
Number of pages9
JournalJournal of the Chemical Society, Perkin Transactions 2
Issue number6
Publication statusPublished - Dec 1 1995

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Alkylation
Vitamin B 12
Enantioselectivity
Strapping
Molecular mechanics
Enantiomers
Nuclear magnetic resonance spectroscopy
Cyclic voltammetry
Methanol
Molecular dynamics
Esters
Derivatives

All Science Journal Classification (ASJC) codes

  • Chemistry(all)

Cite this

Hydrophobic vitamin B12. Part 12. Preparation, characterization and enantioselective alkylation of strapped hydrophobic vitamin B12. / Murakami, Yukito; Hisaeda, Yoshio; Ohno, Teruhisa; Kohno, Hiroshi; Nishioka, Takuya.

In: Journal of the Chemical Society, Perkin Transactions 2, No. 6, 01.12.1995, p. 1175-1183.

Research output: Contribution to journalArticle

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AU - Hisaeda, Yoshio

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AU - Kohno, Hiroshi

AU - Nishioka, Takuya

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