One‐pot synthesis of [¹¹C]ureas via triphenylphosphinimines

A series of 11 C‐labeled ureas was prepared using a rapid and efficient one‐pot procedure. First, the intermediate [ 11 C]phenylisocyanate was formed with phenyltriphenylphosphinimine and [ 11 C]CO 2 . A range of amines was then reacted with the [ 11 C]phenylisocyanate yielding the [ 11 C]urea derivatives in short synthesis times. This easy‐to‐handle method circumvents disadvantages of known procedures and generates the possibility to prepare other kinds of 11 C‐labeled compounds using a variety of phenylphosphinimines in combination with different nucleophiles. The presented approach is an alternative to the use of established methods in 11 C‐labeling chemistry.