Step 1. A solution of diethyl cyanomethylphosphate (39.9 mL, 0.246 mol) in THF (300 mL) was added slowly and dropwise to a solution of 1.0 M potassium tert-butoxide in THF (235 mL) at 0 °C. The ice bath was removed and the reaction mixture was gradually warmed to room temperature and subsequently cooled to 0 °C again. At this temperature, a solution of cyclopentyl formaldehyde (22.0 g, 0.224 mol) in THF (60 mL) was added slowly and dropwise. The ice bath was removed and the reaction mixture was warmed to ambient temperature and stirred continuously for 64 hours. Upon completion of the reaction, the mixture was partitioned between ether and water, and the aqueous phase was extracted three times with ether followed by two extractions with ethyl acetate. The organic phases were combined, washed with brine, dried over anhydrous sodium sulfate, filtered and concentrated under reduced pressure to give 24.4 g (89% yield) of a mixture of (2E)- and (2Z)-3-cyclopentylacrylonitrile, which was used in the subsequent steps without further purification.1H NMR (400 MHz, CDCl3): δ 6.69 (dd, 1H, trans olefin), 6.37 (t, 1H, cis-olefin), 5.29 (dd, 1H, trans-olefin), 5.20 (d, 1H, cis-olefin), 3.07-2.95 (m, 1H, cis-product), 2.64-2.52 (m, 1H, trans-product), 1.98-1.26 (m, 16H).
