Transannular vs Intramolecular Insertion Reactions of Transition Metal Carbenes: Evaluation of a Transannular Approach to Cyclooctane Ring Synthesis
作者:James D. Dudones、Paul Sampson
DOI:10.1016/s0040-4020(00)00893-0
日期:2000.12
The efficacy of closing cyclooctane rings via transannular metal-stabilized carbene insertion reactions within an 11-membered macrocyclic lactone ring was explored. The impact of performing these reactions in a transannular fashion was evaluated via a comparative study of closely analogous intramolecular (but not transannular) processes. Closure of a γ-lactone ring via intramolecular cyclopropanation
探索了通过在11元大环内酯环内进行跨环金属稳定的卡宾插入反应来闭合环辛烷环的功效。通过对紧密相似的分子内(但非环形)过程的比较研究,评估了以环形方式进行这些反应的影响。在Cu(acac)2催化下,通过分子内环丙烷化在中等缺电子的烯烃上封闭γ-内酯环的收率很高,而类似的环戊环丙烷化则受到竞争性β-氢化物迁移的阻碍。相反,使用更富电子的甲氧基取代的烯烃导致成功的环过环丙烷化,以提供所需的含环辛烷环的产物。