Regioselective routes towards 14-hydroxyabietane diterpenes. A formal synthesis of immunosuppressant (-)-triptolide from (+)-abietic acid

Two procedures to introduce an oxygenated function into the C-14 of abietane diterpenes with complete regioselectivity have been developed. Utilizing these, the synthesis of the antileishmanial quinone (-)-12-deoxyroyleanone (1) and a formal synthesis of antitumour and immunosuppressant (-)-triptonide (7) and (-)-triptolide (8) from (+)-abietic acid (13) have been carried out. (c) 2007 Published by Elsevier Ltd.