This paper describes a new chloroperoxidase oxidative activity, namely, pro
pargylic oxidations. Under appropriate conditions, chloroperoxidase catalyz
es the oxidation of a variety of 2-alkynes to aldehydes via alcohol interme
diates. Both hydrogen peroxide and t-butyl hydroperoxide can serve as termi
nal oxidants. The triple bond in the substrate is usually untouched. A free
radical mechanism is proposed for the initial hydroxylation step in the ov
erall reaction. (C) 1998 Academic Press.