Stereoselectivities of nucleophilic additions to cycloheptanones. Experimental and theoretical studies and general purpose force field for the prediction of nucleophilic addition stereoselectivities

被引:15
作者
Ando, K
Condroski, KR
Houk, KN [1 ]
Wu, YD
Ly, SK
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
[4] Univ Ryukyus, Coll Educ, Okinawa 90301, Japan
关键词
D O I
10.1021/jo971627b
中图分类号
O62 [有机化学];
学科分类号
070303 ; 081704 ;
摘要
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.
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页码:3196 / 3203
页数:8
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