Tertiary allylic amines with an electron-deficient alkene react with isocyanates and isothiocyanates to give highly substituted ureas and thioureas arising from formal 1,3-diaza-Claisen rearrangements. Isocyanates and isothiocyanates with strong electron-withdrawing groups are more reactive. Similarly, the data suggest that a stronger electron-withdrawing substituent on the alkene favors a faster reaction
具有电子欠缺烯烃的叔
烯丙基胺与
异氰酸酯和异
硫氰酸酯反应,生成由正规的1,3-二氮杂-克莱森重排产生的高度取代的
脲和
硫脲。具有强吸电子基团的
异氰酸酯和异
硫氰酸酯更具反应性。类似地,数据表明,烯烃上更强的吸电子取代基有利于更快的反应,但是这可以被环状过渡态的空间位阻所抵消。