Synthesis and Characterization of Alkoxycarbonyl Cobalt Complexes via Direct Carbonylation Methods

A series of alkoxycarbonyl cobalt­(III)
complexes has been prepared
by carbonylation of the corresponding aliphatic alcohols. This reaction
proceeds under mild conditions compatible with a wide range of functionalized
alcohols, including alkenes, alkynes, arenes, halides, protected alcohols
and amines. Two different protocols employing both Co­(II) and Co­(III)
complexes as precursors have been developed and proceed with high
efficiency for ligands such as salen and salophen. An unexpected transesterification
was observed to interconvert alkoxycarbonyl products under acid catalysis.
Characterization data, including NMR, IR, and mass spectrometry for
all complexes and two X-ray structures, are provided.