AbstractThe13C chemical shifts in the spectra of friedelan‐7‐one (1), methyl 3‐oxofriedelan‐25‐oate (2), methyl friedelan‐25‐oate (3), 7‐oxofriedelan‐3‐α‐yl acetate (4), friedelan‐3‐one (5), 2‐hydroxy‐3, 4‐seco‐friedelan‐3‐oic acid (6), methyl 2‐oxo‐3,4‐seco‐friedelan‐3‐oate (7), methyl 2‐hydroxy‐3,4‐seco‐friedelan‐3‐oate (8) and 3,4‐seco‐friedelan‐2,3‐diol (9) have been fully assigned using two‐dimensional heteronuclear correlation NMR spectroscopy, BB proton decoupled, DEPT and selective heteronuclear spin decoupling methods. These assignments and the observation of substantial NOEs between 26‐methyl and 28‐methyl and between 28‐methyl and 30‐methyl support the boat to boat conformations for the D and E rings in 1. Corrections a