Alcázar Eva, Pletcher Joseph M, McDonald Frank E
Department of Chemistry, Emory University, Atlanta, Georgia 30322, USA.
Org Lett. 2004 Oct 14;6(21):3877-80. doi: 10.1021/ol0483495.
[reaction: see text] Alkynyldiols 1 undergo cycloisomerization to the corresponding seven-membered cyclic enol ethers 2 under tungsten carbonyl catalysis. This novel transformation proceeds with good yields and virtually complete regioselectivity for all diastereomers of 1, favoring the product 2 resulting from endo-mode cyclization. The unexpected regioselectivity may be dependent on the presence of the dioxolane structure tethering the terminal alkyne and diol functional groups.
[反应：见正文] 在羰基钨催化下，炔二醇1发生环异构化反应生成相应的七元环状烯醇醚2。这种新型转化反应产率良好，对1的所有非对映异构体几乎具有完全的区域选择性，有利于通过内型环化生成产物2。这种意外的区域选择性可能取决于连接末端炔烃和二醇官能团的二氧戊环结构的存在。
