N,N-Diethylaniline → Methyl 4-hydroxy-3-(1-vinylcyclopentyl)benzoate

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A mixture of methyl 4-(2-cyclopentylideneethoxy)benzoate 66.67B (0.50 g, 2.0 mmol), N,N-diethylaniline (3.2 mL, 20 mmol) and N,O-bis(trimethylsilyl)acetamide (2.5 mL, 10 mmol) in a 20 mL seal tube was heated at 240° C. for 48 hours. The reaction was then cooled to room temperature, ether (60 mL) was added, and the mixture was washed with HCl (3N, 20 mL). The organic layer was separated and the solvent was removed. The residue was dissolved in MeOH (10 mL) and HCl (3N, 2 mL) and stirred at room temperature for 30 minutes. Ether (80 mL) was added, and the mixture was washed with NaHCO3 (30 mL) and brine (15 mL). The organic layer was dried over MgSO4. After filtering, the solvent was removed. The residue was purified by Combi Flash silica gel column, eluting with hexane/EtOAc (95/5) to give the compound 66.67C, (0.15 g, yield 30%). 1H NMR (500 MHz, CDCl3) δ ppm 7.90 (1H, d, J=2.2 Hz), 7.80 (1H, dd, J=8.3, 2.0 Hz), 6.81 (1H, d, J=8.3 Hz), 5.99 (1H, dd, J=17.6, 10.5 Hz), 5.77 (1H, s), 5.18 (1H, dd, J=10.5, 1.0 Hz), 5.08 (1H, d, J=17.6 Hz), 3.82 (3H, s), 1.89-2.03 (4H, m), 1.56-1.78 (4H, m). MS ESI (neg.) m/e: 245.1 (M−H)+.

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