bisoxazoline (BOX)/CuII catalyst. This reaction works well with cyclic enol silyl ethers of different sizes, and can be extended to dienol and benzene‐fused substrates, thus providing an effective and general access to a range of 3a‐hydroxy [n.3.0]carbobicycles which are found as a core structure in many natural products. TBDPS=tert‐butyldiphenylsilyl.
新的保险丝:使用新的双恶唑啉(BOX)/ Cu II催化剂实现了标题反应。该反应适用于不同大小的环状烯醇甲硅烷基醚,并且可以扩展至二烯醇和苯稠合的底物,从而提供有效且普遍的接触范围为3a-羟基[ n。3.0]碳双环被发现是许多天然产物的核心结构。TBDPS =叔丁基二苯基甲硅烷基。
Construction of Highly-Functionalized Cyclopentanes from Silyl Enol Ethers and Activated Cyclopropanes by [3+2] Cycloaddition Catalyzed by Triflic Imide
作者:Kiyosei Takasu、Satoshi Nagao、Masataka Ihara
DOI:10.1002/adsc.200600308
日期:2006.11
[3+2] Cycloadditions of silyl enol ethers with donor-acceptor (D-A) cyclopropanes, such as 2-alkoxycyclopropanecarboxylates and 2-(p-methoxyphenyl)cyclopropylphenylketone, proceed in the presence of a catalytic amount of triflic imide (Tf2NH) to give functionalized cyclopentanes in high yield. The catalytic process allows promotion of the cycloaddition of substrates incorporating Lewis basic functions
Highly Diastereoselective Construction of Fused Carbocycles from Cyclopropane-1,1-dicarboxylates and Cyclic Enol Silyl Ethers: Scope, Mechanism, and Origin of Diastereoselectivity
By selecting the appropriate substituents on the ester and silyl groups, fused cyclopentane derivatives with multiple contiguous stereocenters can be synthesized with excellent diastereoselectivity through CuII/bisoxazoline‐catalyzed intermolecular [3+2] cycloaddition reactions of cyclopropane‐1,1‐dicarboxylates and cyclicenolsilylethers (see scheme).
正确的环丙烷环:通过在酯和甲硅烷基上选择合适的取代基,可以通过Cu II /双恶唑啉催化的环丙烷-1,1的分子间[3 + 2]环加成反应,合成具有多个非连续立体中心的稠合环戊烷衍生物。-二羧酸盐和环状烯醇甲硅烷基醚(参见方案)。
Catalytic Asymmetric Simmons−Smith Cyclopropanation of Silyl Enol Ethers. Efficient Synthesis of Optically Active Cyclopropanol Derivatives
作者:Haifeng Du、Jiang Long、Yian Shi
DOI:10.1021/ol0609659
日期:2006.6.1
[reaction: see text] This paper describes a catalytic asymmetric Simmons-Smith cyclopropanation of silyl enol ethers using dipeptide 2 as the ligand. A variety of optically active cyclopropyl silyl ethers can be obtained in high yields. Up to 96% ee was obtained. The dipeptide can be recovered after the reaction in good yield and reused without the loss of reactivity or enantioselectivity.