Base-catalyzed endo-mode cyclization of allenes: easy preparation of five- to nine-membered oxacycles.
Base-catalyzed endo-mode cyclization of allenes: easy preparation of five- to nine-membered oxacycles.
复制标题
DOI：
10.1021/jo0488614
复制
发表时间：
2004-09
期刊：
影响因子：
--
通讯作者：
C. Mukai;Masaru Ohta;H. Yamashita;S. Kitagaki
中科院分区：
文献类型：
--
作者：
C. Mukai;Masaru Ohta;H. Yamashita;S. Kitagaki
开发了一种可靠和有效的方法来构建五元到八元的草环。C_1位既有磷基又有合适的β-羟基烷基侧链的烯烃发生了Endo模式的闭环反应，得到了五元到七元的草环。将磷酰基改变为膦官能团有助于制备八元同系物。在起始烯烃的烷基侧链上引入顺式双键使中等大小的氧环的形成成为可能，例如二氢氧杂环和四氢氧杂环骨架，而不考虑C1-位上的吸电子基团(POPh2，PO(OEt)2，SOPh和SO2Ph)。
A reliable and efficient procedure for constructing five- to eight-membered oxacycles has been developed. Allenes with both a phosphoryl group and a suitable delta-hydroxyalkyl side chain at the C1-position underwent an endo mode ring-closing reaction to give five- to seven-membered oxacycles. Changing the phosphoryl group to a phosphono functionality facilitated the preparation of eight-membered congeners. Introduction of a cis double bond to the alkyl side chain of the starting allenes made possible the easy formation of medium-sized oxacycles, such as the dihydrooxocin and tetrahydrooxonin frameworks, regardless of the electron-withdrawing group (POPh2, PO(OEt)2, SOPh, and SO2Ph) at the C1-position.