Reaction Steps
(2Z)-3-(4-Hydroxy-2-buten-2-yl)-5,6,7,8-tetrahydro-5,5,8,8-tetramethyl-2-(n-propyloxy)naphthalene (Structure 8 of Schemes 1 and 2, where R1, R4, R6=H, R2 and R3 together form a tetramethyl saturated six-membered carbocyclic ring, R5=methyl, R7=n-propyl). To a flame-dried 25-mL r.b. flask containing 3-(4-hydroxy-2-buten-2-yl)-5,6,7,8-tetrahydro-5,5,8,8-tetramethylnaphth-2-ol (133 mg, 0.48 mmol) in 2 mL anhydrous DMF at room temperature was added cesium fluoride (365 mg, 2.40 mmol, 5.00 equiv) and 1-iodopropane (52.0 μL, 0.53 mmol, 1.10 equiv), and the mixture was stirred for 12 h. The reaction mixture was then diluted with EtOAc (20 mL) and the resultant organic layer was washed with water (2×10 mL), brine (10 mL), dried (Na2SO4), and concentrated under reduced pressure to afford 150 mg (99%) of (2Z)-3-(4-hydroxy-2-buten-2-yl)-5,6,7,8-tetrahydro-5,5,8,8-tetramethyl-2-(n-propyloxy) naphthalene as a colorless viscous oil. 1H NMR (400 MHz, CDCl3) 6.91 (s, 1H), 6.77 (s, 1H), 5.78 (dt, 1H, J=6.6, 1.4 Hz), 3.88 (m, 4H), 2.04 (s, 3H), 1.75 (m, 2H), 1.28 and 1.23 (2s, 2×3H), 1.01 (t, 3H, J=7.5 Hz). 13C NMR (100 MHz, CDCl3) 153.3, 144.9, 138.4, 137.0, 127.7, 126.5, 110.1, 70.3, 60.7 35.2, 35.1, 34.4, 33.6, 31.9, 31.8, 25.1, 22.8, 10.7. IR (thin film) 3336 (br, s), 2919 (s), 1498 (m), 1455 (m). Anal. Calcd for C21 H32O2: C, 79.70; H, 10.19. Found: C, 79.60; H, 10.44.
