Decarboxylation Krapcho process

Decarboxylation of (bromodifluoromethyl)malonates (9) reminiscent of Krapcho s deal-koxycarbonylation process, is observed on treatment with potassium fluoride in dimethyl sulfoxide at 170 °C to give 2-(trifluoromethyl)-substituted esters 10.43 The precursors are prepared by reacting diethyl malonates 8 with dibromodifluoromethane in the presence of sodium hydride. The exchange of bromine for fluorine in 9 followed by decarboxylation is an excellent method of introducing a trifluoromethyl group a- to an ester group. 

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