Exchange reactions involving the displacement of hydrogen bonded to ca
rbon by its heavier isotopes are of interest for both mechanistic and
product-orientated research, This review surveys practical strategies
for the preparation of isotopically labelled compounds, discusses rece
nt progress made in developing mild and regioselective exchange protoc
ols, and summarizes the mechanistic aspects of C-H bond activation und
er homogeneous and heterogeneous exchange conditions.