Unusual cyclodimerization of small cyclic ethers via neighboring carbonyl-group participation and cation transfer
作者:Shigeyoshi Kanoh、Tomonari Nishimura、Masashi Naka、Masatoshi Motoi
DOI:10.1016/s0040-4020(02)00702-0
日期:2002.8
cyclodimerization to form a 1,3-dioxolane ring. No phenyl substituent is required in the cases of the oxiranes, because the cation transfer process involves a 1,2-hydride shift alone. These five- and six-membered cyclic acetals are quite different from ring-expanded cyclic ether dimers expected simply from the back-biting reaction known in the cationic ring-opening polymerization of oxiranes and oxetanes.
在3-位同时具有羰基官能团和苯基的氧杂环丁烷在三氟甲磺酸的影响下引起异常的环二聚,从而产生顺式/反式-通过相邻的羰基参与的取代的1,3-二恶烷的异构体混合物,阳离子转移(包括phen重排)和环二聚化。具有羰基官能团的环氧乙烷也经历类似的环二聚反应以形成1,3-二氧戊环。在环氧乙烷类的情况下,不需要苯基取代基,因为阳离子转移过程仅涉及1,2-氢化物转移。这些五元和六元环状缩醛与简单地从环氧乙烷和氧杂环丁烷的阳离子开环聚合反应中已知的反向咬合反应预期的扩环环状醚二聚体完全不同。