[(11) C]Carbon monoxide in labeling chemistry and positron emission tomography tracer development: scope and limitations.

[(11) C]Carbon monoxide is an attractive precursor for labeling carbonyl position in a wide range of organic compounds. The use of [(11) C]carbon monoxide in transition metal-mediated coupling reactions has been explored by several groups during the last 15 years, and an impressive number of the synthesis of [carbonyl-(11) C]compounds have been published to date. The application of radical-mediated [(11) C]carbonylation has also been explored in some extent. However, the main limitations to apply this potential precursor in (11) C-labeling chemistry are low concentration, poor solubility in commonly used organic solvents, and low reactivity. A couple of technical solutions such as high-pressure reactor system, microfluidic system, and different approaches to confine [(11) C]CO to the reaction media at ambient pressure have been developed over the years. Although considerable advances in [(11) C]carbon monoxide chemistry have been reported in recent years, its application in positron emission tomography tracer development is still an area of work in progress. This review summarizes all contributions to the area of radiolabeling using [(11) C]carbon monoxide published between 1995 and 2014 and discusses the scope and limitations of this method in clinical positron emission tomography tracer development.