Reaction Steps
To a flask containing a solution of potassium t-butoxide (6.30 g, 61.1 mmole) in toluene (80 ml), heated to reflux, was added slowly (via syringe pump over 15 hours) a solution of diethyl hexadeca-4E,12E-diene-1,16-dioate (4.32 g, 12.8 mmole) in toluene (10 ml). After the addition was complete the mixture was maintained at reflux for an additional 5 hours. The reaction mixture was cooled to room temperature and to the mixture was added acetic acid and then water. To the mixture was then added diethyl ether, the layers separated and the organic layer was dried with sodium sulfate and evaporated to provide the crude ethyl 15-oxocyclopentadeca-3E,11E-dienecarboxylate which was used directly in the next step. C18H28O3 (292.42 g/mole). 1HNNR (500 MHz, CDCl3): 1.16 (m, 4H), 1.23 (t, 3H), 1.34 (m, 4H), 1.99 (m, 4h), 2.13 (m, 1H), 2.40 (m, 2H), 2.55 (m, 1H), 2.70 (m, 2H), 3.50 (dd, 1H), 4.13 (q, 2H), 5.40 (m, 4H) ppm. 13CNMR (125 MHz, CDCl3): 14.1, 26.2, 27.0, 27.4, 27.7, 28.6, 31.0, 31.1, 31.2, 43.6, 58.4, 61.3, 126.3, 129.1, 131.6, 133.6, 169.5, 204.6 ppm. IR (νmax(cm−1)): 2990, 2940, 2910, 2850, 1745, 1720, 1640, 1440, 1370, 1260, 1040, 970, 860. MS (m/z): 292(M+), 247, 163, 149, 135, 121, 107, 95, 81, 67, 55, 41.
