Synthesis of tricyclopentanoid sesquiterpenes via rearrangement routes: (±)-modhephene, (±)-epimodhephene and (±)-isocomene

Article abstract of DOI:10.1016/0040-4020(95)00486-R

Based on model studies with dispiroundecane 10, dispiroundecane 1 has been synthesized and rearranged to (±)-modhephene 6 and (±)-isocomene 7. The epimeric dispiroundecane 9 yields (±)-epimodhephene 12. A total of thirteen rearrangement products (6, 7, 12, 37, 38, 39, 42, 44, 55, 57, 64, 67) have been isolated from 1 and/or 9, including six unnatural triquinanes. Two of these (55, 57) are formed by unusual 1,3- and 1,4-shifts, respectively. A mechanistic rationale on the basis of force field calculations is given.