A novel ene reaction: Development and applications to the synthesis of (+,-)-phyllanthocin

[摘要] A new reaction has been discovered that forms carbon-carbon bonds at room temperature under catalysis by lanthanide reagents. This reaction occurs between vinyl ethers, which have an oxygen functionality located at the central carbon of the allylic system, and aldehydes and is catalyzed by a 1:1 complex of Yb(fod)$sb3$ and AcOH. The primary product, 3, is not observed but becomes protected, in situ, by excess vinyl ether present as the solvent, or co-solvent, to form the observed product 4. This reaction is very general and proceeds to form pure vinyl ether products in excellent yields.The vinyl ether products formed through the use of this novel reaction can be used to quickly piece together more complex functionalities such as furanones, cyclopentanes, bromoketones, and benzazepinones. Approaches to the efficient syntheses of these compounds and others will be discussed.Phyllanthocin, 5, the aglycon of the potent antitumor agent Phyllanthoside, has been targeted for synthesis using the ene reaction. Furanone formation, using a functionalized vinyl ether formed in the ene reaction, is the primary goal. Applications to the total synthesis of Phyllanthocin will be discussed.$sp*$ ftn$sp*$Please refer to the dissertation for diagrams.

[发布机构] Rice University

[效力级别] chemistry