Generation of chiral boron enolates by rhodium-catalyzed asymmetric 1,4-addition of 9-aryl-9-borabicyclo[3.3.1]nonanes (B-Ar-9BBN) to α,β-unsaturated ketones

被引:44
|
作者
Yoshida, K [1 ]
Ogasawara, M [1 ]
Hayashi, T [1 ]
机构
[1] Kyoto Univ, Grad Sch Sci, Dept Chem, Kyoto 6068502, Japan
来源
JOURNAL OF ORGANIC CHEMISTRY | 2003年 / 68卷 / 05期
关键词
D O I
10.1021/jo020659i
中图分类号
O62 [有机化学];
学科分类号
070303 ; 081704 ;
摘要
Asymmetric 1,4-addition of 9-phenyl-9-borabicyclo[3.3.1]nonane (2m) to 2-cyclohexenone (1a) proceeded with high enantioselectivity in toluene at 80 degreesC in the presence of 3 mol % of a rhodium catalyst generated from [Rh(OMe)(cod)](2) and (S)-binap to give a high yield of boron enolate (S)-3am, which is 98% enantiomerically pure. Reaction of the boron enolate 3am with electrophiles, methanol-d, propanal, and allyl bromide, gave the corresponding 2-substituted (3S)-3-phenylcyclohexanones with perfect regio- and diastereoselectivity.
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页码:1901 / 1905
页数:5
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