Isotope labeling of small molecules is a crucial tool for drug discovery and
understanding biochemical processes. Expanding the toolbox of a radiochemist with
methods that allow late-stage labeling is therefore important. Of the methods that have
been developed, the use of isotopically-labeled *C (* = 14, 13, 11) precursor is among
the most useful platforms for installing isotopically-labeled carbon into the molecule.
While this area has undergone a tremendous amount of development in recent years, the
preparation of *C-labeled molecules (* = 14, 13, 11) remains difficult and time
consuming, with established methods involving label incorporation at an early stage of
synthesis. On the other hand, the development of chemical reactions based on the
reversible cleavage of C-C bonds would offer new opportunities in the preparation of
*C-labeled molecules (* = 14, 13, 11). This review aims to provide a short survey on
the classical and recent methods that provide effective opportunity for late-stage
labeling