The synthesis and use of [14C]carbon monoxide in Pd-catalyzed carbonylation reactions

The [C-14]carbonylation reaction is a very powerful method of incorporating C-14 into a drug molecule late in a radiochemical synthesis. The first and perhaps most critical step in [C-14] carbonylation reactions is the generation of (CO)-C-14 and its subsequent delivery to the reaction flask. There are three published methods for generating (CO)-C-14: conversion of (CO2)-C-14 with Zn at 400 degrees C, pyrolysis of (CaCO3)-C-14, and dehydration of (NaO2CH)-C-14. Additionally, a newly published method for the in situ carbonylation of aryl and vinyl halides to give acids has been investigated using (NaO2CH)-C-14 as the labeled precursor. Finally, the application of (CO)-C-14 in Pd-catalyzed [C-14]carbonylation reactions will be discussed.