positioned alkene bond undergo 5-exo-cyclization with the formation of vinylcyclopentane derivatives. Alkyne analogues provide allenes. The reaction proceeds with a moderate to excellent level of stereoselectivity and allows for asymmetric induction in the reaction with chiral substrate.
具有适当定位的烯键的不饱和氧基烯丙基阳离子经历5-外环化反应,形成
乙烯基环戊烷衍
生物。
炔烃类似物提供
丙二烯。反应以中等至优异的立体选择性
水平进行,并允许与手性底物的反应不对称诱导。