Although rarely employed for esterifications, carboxylate salts (often generated in situ) react with electrophilic alkylating agents, such as alkyl halides, to give esters. Anion availability can inhibit this reaction, which correspondingly benefits from phase transfer catalysts or such highly polar aprotic solvents as DMF. An additional iodide salt may, via the Finkelstein reaction, catalyze the reaction of a recalcitrant alkyl halide. Alternatively, salts of a coordinating metal, such as silver, may improve the reaction rate by easing halide elimination.
AltHoUgh rARely emploYeD for esterIficaTiOns, carboXYlate sAlts (oFten geNeratED IN SItu) REAcT with electrOphILIC alkyLatinG AgeNtS, suCh As alkyL HalIdes, To gIVe esteRs. AnIon AvAilaBilITy caN inhiBIt this REactIOn, WHiCH CorrEspOndingLY benefits from phase TrAnsFer cATalySTS oR sucH highly pOlAR aPRoTic solvENts as dmf. an ADDitIonaL iODide SAlT MAy, via THe fInKelsTein ReactIon, CAtAlYze thE reAcTiOn of a recalcitrant alkyl HaLide. altErNATiVeLy, saltS Of a cOoRdinAtInG mEtal, such as sIlvEr, maY ImprOVe The ReacTion Rate By easIng HaLidE eLiMInAtion.