Hydrophobic vitamin B12. Part 13. Asymmetric reaction of hydrophobic vitamin B12 under electrochemical conditions and rationalization of enantioselectivity based on conformational analysis

Teruhisa Ohno, Takuya Nishioka, Yoshio Hisaeda, Yukito Murakami

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Abstract

The controlled-potential electrolysis of racemic ethyl 3-bromo-2-methoxy-2-phenylpropionate was carried out at -1.8V vs. SCE in N,N-dimethylformamide, as mediated by a simple hydrophobic vitamin B12, [Cob(II)7C3ester]ClO4, and a strapped hydrophobic vitamin B12, [Cob(II)(c,10-PDA)6C3ester]ClO4, to afford ethyl 2-methoxy-2-phenylpropionate and ethyl 2-methoxy-3-phenylpropionate in the dark. The simple hydrophobic vitamin B12 acted to afford ethyl (S)-2-methoxy-2-phenylpropionate, the hydrogen-substituted product, in 55% e.e., while the strapped hydrophobic vitamin B12 was in favor of formation of the corresponding R enantiomer in 26% e.e. Since the reaction proceeds via formation of an intermediate in which the ethyl 2-methoxy-2-phenylpropionate moiety is bound to the hydrophobic vitamin B12, the chiral microenvironment provided by the peripheral groups placed around the corrin framework is responsible for the enantioselective formation of the alkylated hydrophobic vitamin B12. The enantioselective coordination of the substrate species was rationalized by means of molecular mechanics and dynamics computations as well as by Monte Carlo conformational search; the simple hydrophobic vitamin B12 with the S substrate is lower in energy than the complex with the R substrate by l.8 kJ mol-1, while the strapped hydrophobic vitamin B12 with the R substrate is lower than the identical complex with the S substrate by 2.0 kJ mol-1.

Original languageEnglish
Pages (from-to)207-218
Number of pages12
JournalJournal of Molecular Structure: THEOCHEM
Volume308
Issue numberC
DOIs
Publication statusPublished - May 10 1994

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vitamins
Enantioselectivity
Vitamin B 12
Phenylpropionates
Substrates
Electrolysis
Dimethylformamide
Molecular mechanics
Enantiomers
enantiomers
Personal digital assistants
Molecular Dynamics Simulation
electrolysis
Mechanics
Molecular dynamics
Hydrogen
hydrogen
products

All Science Journal Classification (ASJC) codes

  • Biochemistry
  • Condensed Matter Physics
  • Physical and Theoretical Chemistry

Cite this

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title = "Hydrophobic vitamin B12. Part 13. Asymmetric reaction of hydrophobic vitamin B12 under electrochemical conditions and rationalization of enantioselectivity based on conformational analysis",
abstract = "The controlled-potential electrolysis of racemic ethyl 3-bromo-2-methoxy-2-phenylpropionate was carried out at -1.8V vs. SCE in N,N-dimethylformamide, as mediated by a simple hydrophobic vitamin B12, [Cob(II)7C3ester]ClO4, and a strapped hydrophobic vitamin B12, [Cob(II)(c,10-PDA)6C3ester]ClO4, to afford ethyl 2-methoxy-2-phenylpropionate and ethyl 2-methoxy-3-phenylpropionate in the dark. The simple hydrophobic vitamin B12 acted to afford ethyl (S)-2-methoxy-2-phenylpropionate, the hydrogen-substituted product, in 55{\%} e.e., while the strapped hydrophobic vitamin B12 was in favor of formation of the corresponding R enantiomer in 26{\%} e.e. Since the reaction proceeds via formation of an intermediate in which the ethyl 2-methoxy-2-phenylpropionate moiety is bound to the hydrophobic vitamin B12, the chiral microenvironment provided by the peripheral groups placed around the corrin framework is responsible for the enantioselective formation of the alkylated hydrophobic vitamin B12. The enantioselective coordination of the substrate species was rationalized by means of molecular mechanics and dynamics computations as well as by Monte Carlo conformational search; the simple hydrophobic vitamin B12 with the S substrate is lower in energy than the complex with the R substrate by l.8 kJ mol-1, while the strapped hydrophobic vitamin B12 with the R substrate is lower than the identical complex with the S substrate by 2.0 kJ mol-1.",
author = "Teruhisa Ohno and Takuya Nishioka and Yoshio Hisaeda and Yukito Murakami",
year = "1994",
month = "5",
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language = "English",
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journal = "Computational and Theoretical Chemistry",
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T1 - Hydrophobic vitamin B12. Part 13. Asymmetric reaction of hydrophobic vitamin B12 under electrochemical conditions and rationalization of enantioselectivity based on conformational analysis

AU - Ohno, Teruhisa

AU - Nishioka, Takuya

AU - Hisaeda, Yoshio

AU - Murakami, Yukito

PY - 1994/5/10

Y1 - 1994/5/10

N2 - The controlled-potential electrolysis of racemic ethyl 3-bromo-2-methoxy-2-phenylpropionate was carried out at -1.8V vs. SCE in N,N-dimethylformamide, as mediated by a simple hydrophobic vitamin B12, [Cob(II)7C3ester]ClO4, and a strapped hydrophobic vitamin B12, [Cob(II)(c,10-PDA)6C3ester]ClO4, to afford ethyl 2-methoxy-2-phenylpropionate and ethyl 2-methoxy-3-phenylpropionate in the dark. The simple hydrophobic vitamin B12 acted to afford ethyl (S)-2-methoxy-2-phenylpropionate, the hydrogen-substituted product, in 55% e.e., while the strapped hydrophobic vitamin B12 was in favor of formation of the corresponding R enantiomer in 26% e.e. Since the reaction proceeds via formation of an intermediate in which the ethyl 2-methoxy-2-phenylpropionate moiety is bound to the hydrophobic vitamin B12, the chiral microenvironment provided by the peripheral groups placed around the corrin framework is responsible for the enantioselective formation of the alkylated hydrophobic vitamin B12. The enantioselective coordination of the substrate species was rationalized by means of molecular mechanics and dynamics computations as well as by Monte Carlo conformational search; the simple hydrophobic vitamin B12 with the S substrate is lower in energy than the complex with the R substrate by l.8 kJ mol-1, while the strapped hydrophobic vitamin B12 with the R substrate is lower than the identical complex with the S substrate by 2.0 kJ mol-1.

AB - The controlled-potential electrolysis of racemic ethyl 3-bromo-2-methoxy-2-phenylpropionate was carried out at -1.8V vs. SCE in N,N-dimethylformamide, as mediated by a simple hydrophobic vitamin B12, [Cob(II)7C3ester]ClO4, and a strapped hydrophobic vitamin B12, [Cob(II)(c,10-PDA)6C3ester]ClO4, to afford ethyl 2-methoxy-2-phenylpropionate and ethyl 2-methoxy-3-phenylpropionate in the dark. The simple hydrophobic vitamin B12 acted to afford ethyl (S)-2-methoxy-2-phenylpropionate, the hydrogen-substituted product, in 55% e.e., while the strapped hydrophobic vitamin B12 was in favor of formation of the corresponding R enantiomer in 26% e.e. Since the reaction proceeds via formation of an intermediate in which the ethyl 2-methoxy-2-phenylpropionate moiety is bound to the hydrophobic vitamin B12, the chiral microenvironment provided by the peripheral groups placed around the corrin framework is responsible for the enantioselective formation of the alkylated hydrophobic vitamin B12. The enantioselective coordination of the substrate species was rationalized by means of molecular mechanics and dynamics computations as well as by Monte Carlo conformational search; the simple hydrophobic vitamin B12 with the S substrate is lower in energy than the complex with the R substrate by l.8 kJ mol-1, while the strapped hydrophobic vitamin B12 with the R substrate is lower than the identical complex with the S substrate by 2.0 kJ mol-1.

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JF - Computational and Theoretical Chemistry

SN - 2210-271X

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