General procedure for the synthesis of 3-piperidinylphenol from hexahydropyridine and m-bromophenol: N-(3-hydroxyphenyl)piperidine Pd(OAc)2 (129 mg, 0.578 mmol) was added to a mixture of piperidine (2.95 g, 34.68 mmol) and 3-bromophenol (5.00 g, 28.90 mmol). Under nitrogen protection, 2,8,9-tri-tert-butyl-2,5,8,9-tetraaza-1-phosphabicyclo[3.3.3]undecane (397 mg, 1.16 mmol), LiHMDS (66.5 cm3, 1 M in THF), and anhydrous toluene (110 cm3) were added sequentially. The reaction mixture was heated to 80 °C, maintained for 18 h and subsequently cooled to room temperature. Water (50 cm3) was added for partitioning and the aqueous layer was extracted with toluene (3 x 30 cm3). The organic phases were combined, dried over anhydrous sodium sulfate and concentrated under reduced pressure to remove the solvent. Purification by column chromatography [eluent ratio 3:7 ethyl acetate/hexane (Rf = 0.4)] gave an off-white solid product (2.56 g, 50% yield). NMR hydrogen spectrum (250 MHz, CDCl3) δH: 7.11-7.04 (1H, m, aryl ring H), 6.52 (1H, d, J = 8 Hz, aryl ring H), 6.35 (1H, s, aryl ring H), 6.29 (1H, d, J = 8 Hz, aryl ring H), 5.84 (1H, bs, OH), 3.08 (4H, t, J = 5 Hz , 2 × CH2), 1.75-1.62 (4H, m, 2 × CH2), 1.60-1.50 (2H, m, CH2); NMR carbon spectra (62.5 MHz, CDCl3) δC: 156.7, 153.4, 130.0, 109.3, 107.4, 104.6, 51.0, 25.5, 24.2; IR spectra ( KBr) νmax/cm1: 3064, 2959, 2937, 2921, 2856, 1597, 1503, 1454, 1276, 1201, 1133, 1104, 971, 877; mass spectra (ESI) m/z: 178.12 (100%, [M + H]+).
