Reaction Steps
A solution of methyl 4-pentenoate (0.031 g, 0.269 mmol) in THF (1.5 mL) was cooled to 0° C. and 9-BBN (0.5M in THF) (0.574 mL, 0.287 mmol) was added dropwise. The mixture was removed from the ice bath and was stirred at rt for 2 h. To the solution was added a solution of phosphoric acid, potassium salt (1M) (0.448 mL, 0.448 mmol) followed by a solution of (1R,3aS,5aR,5bR,7aR,11aR,11bR,13aR,13bR)-3a-amino-5a,5b,8,8,11a-pentamethyl-1-(prop-1-en-2-yl)-2,3,3a,4,5,5a,5b,6,7,7a,8,11,11a,11b,12,13,13a,13b-octadecahydro-1H-cyclopenta[a]chrysen-9-yl trifluoromethanesulfonate (0.1 g, 0.179 mmol) in 1,4-dioxane (1.5 mL) and finally 1,1′-bis(diphenylphosphino)ferrocenepalladium(II) dichloride, Toluene (7.38 mg, 8.96 μmol). The mixture was heated to 85° C. for 16 h, cooled to rt, diluted with water (15 mL), and extracted with ethyl acetate (3×15 mL). The organic layers were combined, washed with brine, dried over magnesium sulfate, filtered, and concentrated under reduced pressure. The residue was purified by flash chromatography using a 5-50% EtOAc in hexanes gradient and a 12 g silica gel column to give the title compound (0.072 g, 77% yield) as an off-white foam. LCMS: m/e: 524.5 (M+H)+, 2.04 min (method 1). 1H NMR (400 MHz, chloroform-d) δ=5.23 (d, J=5.3 Hz, 1H), 4.73 (d, J=2.0 Hz, 1H), 4.62-4.59 (m, 1H), 3.67 (s, 3H), 2.55 (td, J=10.9, 5.3 Hz, 1H), 2.33 (t, J=7.5 Hz, 2H), 2.09-1.92 (m, 4H), 1.70 (s, 3H), 1.07 (s, 3H), 0.97 (s, 6H), 0.89 (s, 3H), 0.83 (s, 3H), 1.78-0.80 (m, 26H).
