The reaction of potassium hydridopentacarbonylchromate with acrylates. X-ray structure of [PPN]+[CH3CH(COOEt)Cr(CO)5]−

KHCr(CO)5 reacts with methyl acrylate in acetonitrile to give methyl propionate after acid hydrolysis. Monitoring the reaction by IR and NMR spectroscopy showed that the reaction mainly proceeds through the 1,2-addition product K+ [CH3CH(COOMe)Cr(CO)5]−. However, in situ formation of methyl propionate (ca. 15%) before hydrolysis suggests that part of the reaction also occurs through the 1,4-adduct K+ [CH3CHC(OMe)OCr(CO)5]−. The PPN+ salt of the 1,2-adduct obtained from ethyl acrylate was characterized by single crystal X-ray diffraction.