Sodium Iodide → Ethyl 3-phenylprop-2-enoate

Participants

Reaction Steps

Chlorobenzene (1130 mg, 10 mmoles, 1.090 ml) NiBr2 (438 mg, 2 mmoles) and NaI (1650 mg, 11 mmoles) were placed in a dry, degassed, airtight flask and were slurried in DMF (20 ml). The mixture was placed in a 140° C. oil bath for 4 to 5 h during which time it darkened to blue-green or deep red. The solution was cooled to room temperature and ethyl acrylate (1100 mg, 11 mmoles, 1.190 ml), triethylamine (Et3N) (1111 mg, 11 mmoles, 1.530 ml), tri-o-tolyl phosphine (P(otol)3) (1216 mg, 4 mmoles) and palladium dibenzylideneacetone (Pd(dba)2) (29 mg, 0.05 mmoles) were added. A cold finger condenser was affixed under a slow argon flow. The mixture was heated overnight in a 140° C. oil bath, typically 15 to 17 h. The mixture was cooled and mixed with about 100 ml diethyl ether (Et 2 O) to precipitate inorganic salts. If the mixture was to be analyzed by gas chromatography (GC) undecane (0.700 ml) was added as an internal standard. The coupling product was isolated by filtering the Et2O slurry through a 2"×2"(5.08 cm×5.08 cm) silica gel bed packed in a fritted funnel. The crude material was eluted with an additional 200 to 250 ml Et2O. The combined Et2O fractions were washed three times with 15 ml aqueous saturated NaCl solutions, dried over MgSO4, filtered and the solvent removed on the rotary evaporator. Radial chromatography (silica gel, 5:1 volume mixture of hexane and Et2O) afforded 1120 mg (65 mole % yield) of ethyl cinnamate as a yellow oil.

Provenance & Evidence