Synthetic Studies Aimed at (−)-Cochleamycin A. Evaluation of Late-Stage Macrocyclization Alternatives
作者:Leo A. Paquette、Jiyoung Chang、Zuosheng Liu
DOI:10.1021/jo049084a
日期:2004.9.1
adoption of an endo transition state. From this vantage point, two general pathways were subsequently explored as to their suitability for elaboration of the CD rings. Initially examined was a protocol involving 10-membered carbocycle construction. When this approach was demonstrated not to be workable, attention was directed to 10-membered macrolactonization as an alternative tactic. Although assembly of
开发了一种有效的途径,将球菌霉素A的非天然对映异构体完全功能化的ABC环系统。l -(-)-苹果酸和l -(-)-抗坏血酸很好地用作了用于构建(E,Z,E)-1,6,8-壬三烯中间体。通过采用内过渡态通过立体控制的分子内Diels-Alder环加成来组装AB部分结构。从这个有利的角度出发,随后探讨了两种一般途径来研究其适合于CD环的加工。最初检查的是涉及10员碳环化合物构建的方案。当这种方法被证明是行不通的时,人们将注意力转向了十元大环内酯化作为一种替代策略。尽管以这种方式容易地组装C形环,但是六元环的最终闭合以形成环D仍然是一个未解决的问题。