Methyl iodide → Methyl 5-{4-[(4-hydroxyphenyl)(3,3,5,5-tetramethylcyclohexylidene)methyl]phenyl}-4-pentynoate

Participants

Reaction Steps

4-Pentynoic acid (0.50 g, 5.0 mmol) was dissolved in DMF (15 mL). To this solution was added K2CO3 (2.76 g, 20 mmol) followed by CH3I (0.95 mL, 15 mmol). The reaction mixture was stirred at room temperature overnight. Water was added to dissolve all solid, and the mixture was extracted with ether (2×75 mL). The organic extracts were combined and washed with saturated NaHCO3, water, brine and dried over Na2SO4, filtered, and the filtrate was concentrated to give the crude methyl 4-pentynoate as colorless oil (0.29 g, 52%). To a degassed solution of 4-[(4-Iodophenyl)(3,3,5,5-tetramethylcyclohexylidene)methyl]phenol (144) (0.25 g, 0.56 mmol) in DMF (5 mL) were added Pd(PPh3)2Cl2 (40 mg, 0.06 mmol), CuI (11 mg, 0.06 mmol), N,N-diisopropylethylamine (0.45 mL, 2.52 mmol) and methyl 4-pentynoate (0.15 g). The reaction mixture was stirred at room temperature overnight, poured into saturated aqueous NH4Cl (15 mL) and water (5 mL), extracted with ethyl acetate (2×50 mL). The combined organic phase was washed with water, brine, dried over Na2SO4, filtered, and the filtrate was concentrated to give the crude product as brown oil. The crude product was purified by chromatography on a silica gel column eluted with a gradient from hexanes to 20% EtOAc in hexanes to give a light brown solid. The solid was triturated with hot hexanes containing 1% to afford 184 mg (76%) of the title compound (243) as off-white solid. mp 159-160° C. 1H NMR (400 MHz, CDCl3): δ 0.90 (s, 6H), 0.91 (s, 6H), 1.27 (s, 2H), 1.92 (s, 2H), 1.96 (s, 2H), 2.55-2.65 (m, 2H), 2.65-2.75 (m, 2H), 3.71 (s, 3H), 4.58 (s, 1H), 6.72 (d, J=8.4 Hz, 2H), 7.00 (d, J=8.4 Hz, 2H), 7.06 (d, J=8.2 Hz, 2H), 7.28 (d, J=8.3 Hz, 2H). LCMS (ESI): m/z 431 (M+H)+, 429 (M−H)−.

Provenance & Evidence