Synthesis of precursor (−)-9. Reagents and conditions: a) Conc. HCl, 100 °C, 8 days, 96 %; b) 1a,2,7,7a-tetrahydronaphtho[2,3-b]oxirene, K2CO3, EtOH, reflux, 4 days, 62 %; c) BnBr, K2CO3, acetone, 45 °C, overnight, 62 %; d) Separation of enantiomers of 10 on HPLC: Chiralcel OD column 250×10 mm; mobile phase: 60 % isopropanol in hexanes; flow rate: 4.0 ml/min; (+)-enantiomer at 22 min and (−)-enantiomer at 49 min; e) (−)-10, 10 % Pd/C, MeOH, 70 psi, 21 h, 90 %.