ABSTRACT
Like most photochemical reactions, benzylic fragmentation has been known from the beginning of the twentieth century. The photoinduced cleavage of triphenylmethylcarbinol has been noted by Gomberg in Ann Arbor in 1913 [1] and the generation of triarylmethyl cationic dyes from their leuco form by Lifschitz in Zu¨rich in 1919 [2]. A solution of the colorless derivative obtained from p-rosaniline and cyanide became colored in a few seconds when exposed to an iron arc lamp (Sch. 1, old and new notation).
