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

The [ 14 C]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 [ 14 C]carbonylation reactions is the generation of 14 CO and its subsequent delivery to the reaction flask. There are three published methods for generating 14 CO: conversion of 14 CO 2 with Zn at 400°C, pyrolysis of Ca 14 CO 3, and dehydration of NaO   14 2 CH. Additionally, a newly published method for the in situ carbonylation of aryl and vinyl halides to give acids has been investigated using NaO   14 2 CH as the labeled precursor. Finally, the application of 14 CO in Pd‐catalyzed [ 14 C]carbonylation reactions will be discussed. Copyright © 2010 John Wiley & Sons, Ltd.