2,4-Dichloro-1-iodobenzene → (E)-2-(2,4-dichlorophenyl)-butendioic acid diethyl ester

Beteiligte Stoffe

Reaktionsbedingungen

Reaktionsschritte

A suspension of magnesium (0.73 g, 0.03 moles) in ethyl ether (20 ml) under nitrogen flow was added with ethyl bromide (50 mg). The solution was stirred for 15 minutes then added with a solution of 1,3-dichloro-4-iodobenzene (5.45 g, 0.02 moles) in ethyl ether (10 ml) in 1 hour keeping the temperature at 18-22° C. At the end of the addition the suspension was kept under stirring for 90 minutes at 18-22° C., then decanted and the surnatant added in 10 minutes to a suspension of dry zinc chloride (5.4 g, 0.04 moles) in ethyl ether (8 ml). At the end of the addition the stirring was kept on at 20° C. for further 90 minutes, then cooled to 0° C. DMF (10 ml) and palladium dichloride triphenylphosphine (351 mg, 0.0005 moles), then a solution of diethyl iodo-fumarate (4.18 g, 0.014 moles) in DMF (4 ml) were added. The mixture was kept under stirring for 15 hours at 25° C. and after a work-up similar to the one of point a) 2.1 g of (E)-2-(2,4-dichlorophenyl)-butendioic acid diethyl ester were yielded (yield: 63% calculated with respect to the iodo-furmarate).

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