Synthesis of alkyl(alkoxycarbonyl)tetracarbonyliron complexes [(Co)4Fe(CH2CO2Me)(CO2R)]: the first evidence of their relevance to the catalytic cycle in the carbonylation of organic halides induced by pentacarbonyliron

Abstract

Reaction of [(CO)₄Fe(CO₂R)]^–(1)(R = Me or Bu^t) with BrCH₂CO₂Me produces stable complexes [(CO)₄Fe(CH₂CO₂Me)(CO₂R)](3) which thermally decompose to yield Fe(CO)₅ and malonic esters under a CO atmosphere; these reactions provide the first demonstration of possible key steps in the catalytic cycle of the carbonylation of reactive halides into esters with Fe(CO)₅ and an alkoxide anion.