(Triphenylphosphoranylidene)acetonitrile → (E)-Methyl 4,5-dichloro-2-(2-cyanovinyl)benzoate

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Reaction Steps

A mixture of the product from Example 56C (2.0 g, 8.6 mmol) and (triphenylphosphoranylidene)acetonitrile (2.87 g, 9.5 mmol) in toluene (30 mL) was refluxed for 24 hours. The reaction was cooled to room temperature and filtered through a short plug of silica gel eluting with diethyl ether to remove the triphenyl phosphine oxide. The filtrate was concentrated and the residue was purified via flash chromatography on a silica gel:column (5:95 ethyl acetate:hexane) to afford the title compound and the corresponding Z isomer. 1H NMR (300 MHz, DMSO-d6) δ ppm 3.88 (s, 3H) 6.55 (d, J=16.27 Hz, 1H) 8.05 (d, J=16.95 Hz, 1H) 8.09 (s, 1H) 8.13 (s, 1H); MS (DCI+) m/z 273.0 [M+H]+.

Provenance & Evidence