e breaks preferentially to the syn bond. It is suggested that the product determining step involves an intramolecular radical displacement of nitrogen, as well as an electrocyclic rotation of the allylic methylene groups of the diazenyl allyl diradical, to generate the cyclopropane ring concerted with the loss of nitrogen. The position of deuterium in the methylmethylenecyclopropane can best be rationalized
次级
氘动力学同位素效应表明CN键反向Me基团上4-亚乙基-1-
吡唑啉场所优先于顺式键。建议产物确定步骤涉及氮的分子内自由基置换,以及
二氮烯基烯丙基二自由基的烯丙基亚甲基的电环旋转,以产生与氮损失协同作用的
环丙烷环。
氘在甲基
亚甲基环丙烷中的位置可以通过后面的步骤来最好地合理化。