Reaction Steps
A solution of (6aR,10aR)-6,6,9-trimethyl-3-pentyl-6a,7,10,10a-tetrahydro-6H-benzo[c]chromen-1-yl trifluoromethanesulfonate (S30) (410 mg, 0.92 mmol, 1 equiv) in anhydrous dichloroethane (20 ml) was degassed with a steady stream on N2 for 20 min. To the solution was added PdCl2dppf.CH2Cl2 (113 mg, 0.19 mmol, 0.2 equiv), 4,4,5,5-Tetramethyl-1,3,2-dioxaborolane (400 μl, 2.76 mmol, 3 equiv) and triethylamine (770 μl, 5.52 mmol, 6 equiv). The mixture was heated to 80° C. under an atmosphere of N2 for 11 h. The reaction mixture was cooled to room temperature and concentrated in vacuo. The residue was purified by chromatography on silica gel eluting with benzene/hexanes 4/6 (v/v) to afford 373 mg of the title compound as white semi solid (92% yield). Rf=0.32 (benzene/hexanes 1:1 (v/v)). 1H NMR (600 MHz, CDCl3, 20° C., δ): 7.09 (d, J=2 Hz, 1H) 6.71 (d, J=2 Hz, 1H) 5.44 (bd, J=4 Hz, 1H) 2.99 (dt, J=5 Hz, J=11 Hz, 1H) 2.60 (bdd, J=5 Hz, J=15 Hz, 1H) 2.49−2.52 (m, 2H) 2.10−2.17 (m, 1H) 1.83−1.90 (m, 2H) 1.74 (dt, J=5 Hz, J=12 Hz, 1H), 1.68 (s, 3H) 1.59 (p, J=8 Hz, 2H) 1.38 (s, 3H) 1.36 (s, 6H) 1.34 (s, 6H) 1.28−1.33 (m, 4H) 1.14 (s, 3H) 0.88 (t, J=7 Hz, 3H) 13C NMR (100 MHz, CDCl3, 22° C., δ): 152.9, 141.4, 134.5, 128.5, 128.1, 120.0, 119.9, 83.5, 76.1, 45.5, 40.4, 35.4, 33.5, 31.7, 30.9, 28.2, 27.5, 25.1, 24.6, 23.2, 22.6, 18.5, 14.0 (C-B not observed). 11B NMR (96 MHz, CDCl3, 22° C., δ): 29.9. Mass Spectrometry: HRMS-FIA (m/z): Calcd for [C27H41BO3+H], 425.32215. Found, 425.32224.
