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

A series of ¹¹C-labeled ureas was prepared using a rapid and efficient one-pot procedure. First, the intermediate [¹¹C] phenylisocyanate was formed with phenyltriphenylphosphinimine and [ ¹¹C]CO₂. A range of amines was then reacted with the [¹¹C]phenylisocyanate yielding the [¹¹C]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 ¹¹C-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 ¹¹C-labeling chemistry.