Acrylonitrile → (E)-Methyl 3-(2-cyanovinyl)picolinate

Beteiligte Stoffe

Reaktionsbedingungen

Reaktionsschritte

A microwave vial were charged with methyl 3-bromopicolinate (2.84 g, 13.15 mmol), acrylonitrile (0.907 g, 17.09 mmol), N,N-dicyclohexylmethylamine (3.08 g, 15.78 mmol), tri-tert-butylphosphine (0.789 mL, 0.789 mmol, 1 M in toluene), tris(dibenzylideneacetone)dipalladium (0) (0.361 g, 0.394 mmol) and 10 mL of 1,4-dioxane under nitrogen. The reaction mixture was capped and heated to 80° C. in an oil bath for 20 hours. The reaction mixture was diluted with ethyl acetate and filtered. The filtrate was concentrated, and the residue was triturated with ethyl acetate to give the title compound as a solid as the first batch. 1H NMR analysis showed only the trans isomer. The mother liquor was concentrated, and the residue was purified by silica gel flash column chromatography eluting with 20-50% ethyl acetate in hexane to give a second batch of the title compound. 1H NMR analysis showed indicated only trans product. 1H NMR (300 MHz, DMSO-d6) δ ppm 8.70 (dd, J=4.6, 1.6, 1H), 8.27 (dd, J=8.1, 1.6, 1H), 8.04-7.94 (m, 1H), 7.71 (dd, J=8.1, 4.6, 1H), 6.53 (d, J=16.5, 1H), 3.91 (s, 3H).

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