This radical attacks the carbonyl group to an intermediate bicyclic ketyl.
烷基自由基对羰基进行进攻，生成双环的羰自由基中间体。
2
When the amine was used as a triplet quencher, the ketyl radical of ketocoumarin can be observed evidently.
当以胺类化合物为猝灭剂时，可以清楚地观察到半片呐醇自由基的生成，并得到了它的瞬态吸收光谱。
3
Methods and recent development of isolation of structurally characterizable alkali, alkaline earth and lanthanide metal ketyl radical complexes were reviewed in the paper.