Absolute Configuration of Mutilin, 5-Acetylmutilin and 5-Bromoacetylmutilin

Abstract

The structures of the tricyclic diterpenoids mutilin, C 20 H 32 O 3 , (1), 5-acetylmutilin, C 22 H 34 O 4 , (2), and 5-bromoacetylmutilin, C 22 H 33 BrO 4 , (3), are reported (mutilin is 6-ethenyldecahydro-5,8-dihydroxy-4,6,9,10-tetramethyl-1-oxo-3a,9-propano-3aH-cyclopentacyclooctene). All these compounds present similar conformations, confirming the rigidity of their common tricyclic skeleton. The absolute configuration of these natural products is confirmed by the X-ray diffraction analysis of the bromo derivative (3).