Sequential ring-closing metathesis/Pd-catalyzed, Si-assisted cross-coupling reactions: general synthesis of highly substituted unsaturated alcohols and medium-sized rings containing a 1,3-cis–cis diene unit
作者:Scott E. Denmark、Shyh-Ming Yang
DOI:10.1016/j.tet.2004.06.149
日期:2004.10
construction of medium-sized rings with an internal 1,3-cis–cis diene unit. The formation of 9-, 10-, 11-, and 12-membered carbocyclic dienes is achieved in good yield. Extension to the synthesis of 9-membered ring unsaturated ethers has also been accomplished. Noteworthy features of this process include: (1) highly stereospecific intramolecular coupling, (2) flexible positioning of the revealed hydroxy group
已经开发了顺序闭环复分解/硅辅助交叉偶联方案。烯丙基,均烯丙基和双(均烯丙基)醇的烯基二甲基甲硅烷基醚用Schrock催化剂进行容易的闭环,分别得到5、6和7元环烯基硅氧烷,在某些情况下在两个烯基碳上均具有取代基。这些硅氧烷是高效偶联剂,可以高产率,高特异性和良好的官能团相容性提供苯乙烯和二烯(具有各种芳基和烯基卤化物)。在[allylPdCl] 2的存在下,带有Z-碘链烯基醚的硅氧烷会经历分子内偶联过程,这是构造具有内部1,3-内径的中型环的有效方法顺式–顺式二烯单元。9元,10元,11元和12元碳环二烯的形成以良好的收率实现。还已经完成了对9元环不饱和醚的合成的扩展。该过程的值得注意的特征包括:(1)高度立体定向的分子内偶联,(2)显露的羟基的灵活定位,以及(3)可能扩展到其他中型碳环和杂环。