Intermolecular cyclopropanation versus CH insertion in RhII-catalyzed carbenoid reactions

被引:88
|
作者
Müller, P [1 ]
Tohill, S [1 ]
机构
[1] Univ Geneva, Dept Organ Chem, CH-1211 Geneva 4, Switzerland
关键词
diazo decomposition; CH bond insertion; rhodium catalyst; asymmetric induction;
D O I
10.1016/S0040-4020(00)00076-4
中图分类号
O62 [有机化学];
学科分类号
070303 ; 081704 ;
摘要
The product ratio of intermolecular insertion and cyclopropanation in transition metal-catalyzed diazo decompositions depends strongly upon the metal, its ligands and upon the substituents of the diazo compound. Ethyl diazoacetate (2a) reacts with cyclohexene (1) almost exclusively by cyclopropanation. However, diazomalonate (2d) and methyl 2-diazophenylacetate (2e) in the presence of Rh-II catalysts exhibit a marked tendency towards allylic CH insertion. With 1,4-cyclohexadiene (6), methyl 2-diazophenylacetate (2e) in the presence of chiral Rh-II catalysts affords the allylic insertion product 7 in almost quantitative yield and with up to 74% ee. (C) 2000 Elsevier Science Ltd. All rights reserved.
引用
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页码:1725 / 1731
页数:7
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