Tetrahedron Letters. Vol. 38. No. 41, pp. 7249-7252, 1997 Pergamon © 1997 Elsevier Science Ltd All rights reserved. Printed in Great Britain PII: S0040-4039(97)01683-3 0o40-4039/97 $17.00 + 0.00 Total Synthesis of both Enantiomers of 15-Oxopuupehenol Methylendioxy Derivatives Od6n Arjona*, Maria Garranzo 1, Jestis Mahugo, Eduardo Maroto, Joaqufn Plumet* and Beatriz S~iez1 Departamento de Qutmica Org~mica I, Facultad de Qulmica, Universidad Complutense, 28040 Madrid, Spain Dedicated to Prof. Luigi Minale in memoriam Abstract :The total synthesis of both enantiomers of puupehenol and 15-oxopuupehenol as methylenedioxy derivatives is described. The key steps of the synthesis are the regioselective transformation of 10 to 11 and the stereoselective cyclization of 12 to 13. © 1997 Elsevier Science Ltd. (+)-Puupehenone 1 and (-)-15-oxopuupehenol 2 are metabolites isolated from two Hawaiian sponges Hyrtios sp 2 showing a sesquiterpene unit joined to a C-6 shikimate moiety. Both compounds show interesting biological properties including cytotoxic, antiviral and antifungal activities for 1 and antitumor, antimalarial and inhibition of Topoisomerase II activities for 2. 2 OH OH Oo 1 2 A previous synthesis of racemic 1 has been reported by Trammel 3 starting from farnesyl bromide and sesamol, whereas, to the best of our knowledge, the synthesis of 2 has never been published. A recent report of Barrero et al. 4 concerning the enantiospecific synthesis of (+)-l from (-)-sclareol 3 and protocatechualdehyde 4 involving 15 synthetic steps prompted us to report our results in this field. OH OH 3 4 7249