Ethylene Glycol → Ethyl 1,4-dioxaspiro(4.5)decane-8-carboxylate

Participants

Reaction Conditions

Reaction Steps

A mixture of ethyl 4-oxocyclohexanecarboxylate (25 g), 10-campharsulfonic acid, ethylene glycol (40 mL), and toluene (400 mL) was heated under reflux with a Dean-Stark apparatus for 2.5 h (bath temp. 135° C.). The mixture was cooled down, and then was diluted with ether (200 mL). After the ethylene glycol layer was separated, the organic layer was washed with saturated aqueous sodium bicarbonate solution (2×) and brine (1×), dried over MgSO4, and filtered. The filtrate was evaporated in vacuo to give 2 as an oil (31.29 g, 99%): 1H NMR (CDCl3) δ 4.13 (2H, q, J=7.1 Hz), 3.95 (4H, s), 2.33 (1H, m), 1.93 (2H, m), 1.79 (4H, m), 1.56 (2H, m) 1.25 (3H, t, J=7.1 Hz); 13C NMR (CDCl3) δ 175.4, 108.3, 64.5, 60.5, 41.8, 33.9, 26.5, 14.4.

Provenance & Evidence