The most stable biradical rule,which was put forward at the beginning of the discovery of the P-B reaction,was used to explain its regioselectivity.

在P-B反应发现之初,人们一直用“最稳定的双自由基规则”解释其区域选择性,这一规则对有些体系却不适用,近年来有人开始运用“自旋化学”理论来解释区域选择性。