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. Copyright © 2006 John Wiley & Sons, Ltd.