regioselectivity of the radical cyclisation, which can proceed via either a 4-exo or 5-endo pathway, to form β- or γ-lactam products respectively, is determined by the nature of the metal oxidant and the reaction conditions. Thus, whereas copper(I)/bipyridine reactions give predominantly γ-lactams, the use of copper(I)/TMEDA or dichlorotris(triphenylphosphine)ruthenium(II) affords mainly β-lactams.
已经研究了各种卤代酰胺与
铜(I)或
钌(II)配合物的环化作用。自由基环化的区域选择性可以通过4- exo或5- endo途径进行,分别形成β-或γ-内酰胺产物,这取决于
金属氧化剂的性质和反应条件。因此,尽管
铜(I)/联
吡啶反应主要产生γ-内酰胺,但是使用
铜(I)/ TME
DA或二
氯三(
三苯基膦)
钌(II)主要提供β-内酰胺。