ratio cyclized / uncyclized increases in the order Cl < Br < I. This ratio decreases when the ratio Mg / RX increases suggesting that the radicals formed by E.T from Mg to RX may be trapped by Mg at a rate competitive with the rate of cyclization of a norbornenyl radical.
内-5-(2'-卤乙基)-2-
降冰片烯(X = I,Br,Cl)与通过
金属汽化获得的活性Mg的反应会同时生成环化和未环化的
有机镁化合物。环化/未环化的比率按Cl