3,4-dihydro-2H-pyran → 2-(2-Bromoethoxy)tetrahydro-2H-pyran

Participants

Reaction Steps

To a mechanically stirred solution of dihydropyran (1000 mL) and a strong acid resin (10.0 g) in hexane (2000 mL) was added 2-bromoethanol (985 g) dropwise over a period of 1.5 hours in a cold water bath to maintain an internal temperature of 35°-40° C. After being stirred overnight at room temperature, the reaction mixture was chromatographed, with hexane as the eluent. The hexane was evaporated to give an amber liquid which was distilled through a 2 inch (5 cm) diameter vigreux cole, collecting the material boiling between 75°-95° C. (3,300-4,700 Pa). This material was redistilled to give the ether as an oil (1195.5 g); bp 80°-90° C. (2666 Pa); NMR: 4.68 (m, 1), 4.01 (m, 1), 3.89 (m, 1), 3.77 (m, 1), 3.52 (m, 3), 1.75-1.50 (m, 6).

Provenance & Evidence