p-Toluenesulfonic acid → 2-[(7-Bromoheptyl)oxy]tetrahydro-2H-pyran

Participants

Reaction Steps

Dihydropyran (5.20 g, 6.11 mmol) was added to a stirring 0° C. solution of 7-bromoheptane-1-ol (2) (11.0 g, 56.7 mmol) and a catalytic amount of PTSA in CH2Cl2. After stirring at rt for 12 h, the reaction mixture was diluted with CH2Cl2 (200 mL), washed with water (100 mL×2), brine (100 mL×3), dried over anhydrous sodium sulphate, and evaporated. The residue was purified by silica gel column chromatography using a gradient of 10-20% ethyl acetate/hexane as eluent to give 2-(7-bromoheptyloxy)tetrahydro-2H-pyran (3) (14.50 g, 92%) as a colorless oil. TLC: 10% EtOAc/hexanes, Rf≈0.55; 1H NMR (400 MHz, CDCl3) δ 4.58-4.56 (m, 1H), 3.84-3.88 (m, 1H), 3.68-3.77 (m, 1H), 3.46-3.51 (m, 1H), 3.33-3.43 (m, 3H), 1.80-1.81 (m, 2H), 1.30-1.62 (m, 14H).

Provenance & Evidence