Zinc powder (135.00 g, 2.065 mol) and copper (I) bromide (5.00 g, 0.035 mol) were suspended in 1,2-dimethoxyethane (1820 mL) under nitrogen protection. The mixture was heated to 75 °C and stirred for 20 min. Next, acetic acid (4.5 mL, 0.078 mol) and isopropanol (9.5 mL, 0.124 mol) were added to the system and stirred at 72 °C. A solution of dibromomethane (334 g, 1.921 mol) in 1,2-dimethoxyethane (114 mL) was added slowly dropwise, with the rate of acceleration of the drop being controlled to maintain the reaction temperature at about 75 °C. The reaction mixture was stirred for 1 hour until TLC analysis showed complete conversion of the feedstock. After addition of ethyl acetate (2500 mL), the system was cooled to 0-5 °C. A 5% aqueous acetic acid solution (2500mL) was added slowly and stirring was continued for 30 minutes. The solid was collected by filtration and the liquid phase was separated. The aqueous layer was extracted twice each with ethyl acetate (1250 mL, 500 mL) and the combined organic phases were washed twice with distilled water (2 x 2500 mL) and separated. The organic solvent was removed under reduced pressure at 45 °C and the residue was dissolved in diisopropyl ether (560 mL), stirred, filtered and washed twice with diisopropyl ether. The resulting (2S,4aR,4bS,6aS,7aS,8aS,8bS,8cR,8dR,9aR,9bR)-2.9b-dihydroxy-4a,6a-dimethyloctadecyl-7H-cyclopropa[4,5]cyclo-penta[1,2-a]cyclopropa[l]phenanthracenecarbenecarbenone 7-ketone was dried in vacuo at 45 °C to give the product 74.50 g (0.225 mol, 71% yield). The product was structurally confirmed by 1H-NMR and 13C-NMR, and HPLC-MS (ESI) analysis showed [M + Na]+ = 353 and [2M + Na]+ = 683.
![(3b,5b,15a,16a)-15,16-Dihydro-3,5-dihydroxy-3'H-cycloprop[15,16]androsta-6,15-dien-17-one](/CAS/GIF/82543-15-5.gif)
