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应发现之初,人们一直“最稳定的双自由基规则”解释其域选择性,这一规则对有些体系却不适,近年来有人开“自旋化学”理论来解释域选择性。