METALS IN ORGANIC SYNTHESES. V. THE GATTERMAN-KOCH SYNTHESIS OF AROMATIC ALDEHYDES PROMOTED BY CuCi(PPh3)n (n=0,1 or 3). IS THE CUPROUS COMPLEX NECESSARY IN THE SYNTHESIS OF TOLUALDEHYDE ?

Article abstract of DOI:10.1016/S0022-328X(00)86671-1

The use of CuCl(PPh3) in place of CuCl in the Gattermann-Koch synthesis slightly improves the yield of benzaldehyde but lowers the yield of tolualdehyde.The poorest yields are obtained in the presence of CuCl(PPh3)3.The formation of tolualdehyde from toluene and carbon monoxide in the presence of AlCl3 and HCl is faster in the presence of CuCl, but higher yields are obtained in its absence and using an excess of hydrocarbon.In competitive experiments carried out using benzene and toluene together in equimolecular amounts, only tolualdehyde was formed, supporting the view that an electrophilic substitution is involved.