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现之初,们一直用“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用,近年来有运用“自旋化学”理论来解释域选择性。