作者:Alois Fürstner、Klaus Langemann
DOI:10.1055/s-1997-4472
日期:1997.7
The ruthenium carbene complexes 1 and 2 (0.05-5 mol%) catalyse highly efficient macrocyclization reactions of 1,Ï-dienes by ring-closing metathesis (RCM). Key parameters for successful RCM are (i) the presence of a functional group which serves as a relay entity that assembles the reacting sites, (ii) an appropriate distance between this polar group and the alkenes to be metathesized, and (iii) low steric congestion near the double bonds. Contrary to previous assumptions, however, the ring size formed and the conformational predisposition of the substrates for ring closure turned out to be of minor importance. These aspects are illustrated by some straightforward syntheses of macrocyclic lactones, lactams, ethers and ketones, including the musk odored perfume ingredients Exaltolide, Exaltone and Arova 16, of the macrolide recifeiolide (24), as well as of the alkaloids epilachnene (40) and its homologue 9-propyl-10-azacyclododecan-12-olide (39), which are active principles of the defense secretions of the pupae of the mexican beetle Epilachnar varivestis .
钌卡宾配合物1和2(0.05-5 mol%)催化通过环闭合重排(RCM)进行的高效大环化反应,涉及1,ω-二烯。成功进行RCM的关键参数为:(i) 存在一个功能团,作为中介实体,组装反应位点;(ii) 该极性基团与要重排的烯烃之间的适当距离;(iii) 双键附近较低的立体拥挤。然而,与之前的假设相反,形成的环大小和底物的环闭合构象倾向被证明重要性较小。这些方面通过一些简单的合成示例得以说明,包括大环内酯、内酰胺、醚和酮的合成,其中包括带有麝香气味的香料成分Exaltolide、Exaltone和Arova 16,以及大环药物recifeiolide (24),以及生物碱epilachnene (40)及其同分异构体9-丙基-10-氮杂环十二烷-12-内酯 (39),这些都是墨西哥甲虫Epilachnar varivestis蛹的防御分泌物的活性成分。