Stereoselectivities of nucleophilic additions to cycloheptanones. Experimental and theoretical studies and general purpose force field for the prediction of nucleophilic addition stereoselectivities
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作者:
Ando, K
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机构:Univ Calif Los Angeles, Dept Biochem & Chem, Los Angeles, CA 90095 USA
Ando, K
Condroski, KR
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机构:Univ Calif Los Angeles, Dept Biochem & Chem, Los Angeles, CA 90095 USA
Condroski, KR
Houk, KN
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Univ Calif Los Angeles, Dept Biochem & Chem, Los Angeles, CA 90095 USAUniv Calif Los Angeles, Dept Biochem & Chem, Los Angeles, CA 90095 USA
Houk, KN
[1
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Wu, YD
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机构:Univ Calif Los Angeles, Dept Biochem & Chem, Los Angeles, CA 90095 USA
Wu, YD
Ly, SK
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机构:Univ Calif Los Angeles, Dept Biochem & Chem, Los Angeles, CA 90095 USA
Ly, SK
Overman, LE
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机构:Univ Calif Los Angeles, Dept Biochem & Chem, Los Angeles, CA 90095 USA
Overman, LE
机构:
[1] Univ Calif Los Angeles, Dept Biochem & Chem, Los Angeles, CA 90095 USA
[2] Hong Kong Univ Sci & Technol, Kowloon, Hong Kong
[3] Univ Calif Irvine, Dept Chem, Irvine, CA 92717 USA
The selectivities of nucleophilic additions of ethyl, vinyl, and ethynyllithium and Grignard reagents to a 2-(3'-phenylpropyl)cycloheptanone were investigated experimentally. In all cases, cis-cycloheptanol was formed preferentially (40:1-6:1). Theoretical studies were performed on the stereoselectivities of nucleophilic additions of hydride and ethynyllithium reagents to cycloheptanones. An empirical force field for transition states of hydride and ethynyl reagents was used for transition-state geometries and conformational searches. Quantum mechanical calculations on HLi addition to cycloheptanones were compared to the corresponding cyclohexanone calculations. These results show that the formation of 2-alkyl-substituted cis-cycloheptanols is preferred for all nucleophiles studied as a result of torsional and steric effects in the transition states of these reactions.