and structure (2) confirmed; a possible mechanism for the transformation involving free radicals is suggested. In contrast, the bromination (5)→(2) reported by Hill and Cornelison in 1894 could not be repeated despite many attempts. An ionic mechanism for the preparation (4)→(6) is proposed; the semi-aldehyde (6) in solution exists solely in the lactol form (7).
托里(Torrey)在1897年记录的固态光氧化(1)→(2)已得到验证,结构(2)得到确认;提出了一种可能的涉及自由基转化的机制。相比之下,希尔和科尼利森在1894年报道的
溴化反应(5)→(2)尽管经过多次尝试却无法重复。提出了制备(4)→(6)的离子机理。溶液中的半醛(6)仅以内酯形式(7)存在。