1,4,7,10-Tetrazacyclododecane (aka Cyclen) is commonly used as catalyst in the cyclen-catalyzed Henry reaction of aldehydes with nitroalkanes under mild and neutral conditions. It is also employed in the preparation of Gadobutrol as a gadolinium-based magnetic resonance imaging (MRI) contrast agent (GBCA).
Cyclen-catalyzed Henry reaction under neutral conditions. [1]
