Deprotonation of o-hydroxybenzyl acetate with (i)PrMgCl provides a method of generating an o-quinone methide under mild, anionic conditions, such that highly sensitive exo-enol ethers can be employed as 2pi partners in hetero-Diels-Alder reactions. This process results in mono-benzannelated spiroketals such as those found in the natural products berkelic acid, the chaetoquadrins or cephalostatin 6
用(i)PrMgCl对
乙酸邻羟基苄酯进行质子化提供了一种在温和的阴离子条件下生成邻醌甲基化物的方法,这样,在杂Diels-Alder反应中可以使用高度敏感的外烯醇醚作为2pi配偶体。这个过程会产生单苯甲酰化
螺环酮,例如在
天然产物伯克力酸,甲壳草木苷或头孢
抑素6中发现的
螺环酮。