作者:Benjamin D. Brink、Justin R. DeFrancisco、Julie A. Hillner、Brian R. Linton
DOI:10.1021/jo200346r
日期:2011.7.1
While hydroxybenzotriazole is commonly used in a variety of bond-forming reactions, its acylation has been shown to produce a regiochemical (O vs N) mixture with complex kinetic behavior. Increased steric bulk on the electrophile favors formation of the oxygen-acylated product. Upon standing as a solid, the mixture can isomerize completely to the nitrogen adduct. An equilibrium ratio of regioisomers
尽管羟基苯并三唑通常用于各种形成键的反应中,但已表明其酰化作用会产生具有复杂动力学行为的区域化学混合物(O对N)。亲电试剂上增加的空间体积有利于氧酰化产物的形成。静置为固体后,混合物可以完全异构化为氮加合物。通过添加亲核试剂或亲电试剂,可以在溶液中重新建立区域异构体的平衡比,这表明混合物的组成对随后的反应性并不重要。溶剂可以通过科廷-汉米特效应来影响这种区域化学平衡,其中极性溶剂中HOBt的互变异构平衡的偏移会将反应偏向氧加合物。