Hydromorphone and hydrocodone are widely used narcotic analgesics. In this mini-review article, processes for the preparation of these semi-synthetic opioids from the naturally occurring opiates morphine and codeine, respectively, via catalytic isomerization of the allylic alcohol unit of the latter are discussed. Relevant patents in the field are presented.

Codeine, hydrocodone, hydromorphone, morphinan derivatives, morphine, redox isomerization of allylic alcohols, transition-metal complexes.

Departamento de Quimica Organica e Inorganica, Facultad de Quimica, Universidad de Oviedo, Julian Claveria 8, E-33006 Oviedo, Spain.