Ruthenium catalysed redox transformation of cinnamaldehyde to 3- phenylpropionic acid and methyl ester

Article abstract of DOI:10.1016/S0040-4039(98)01827-9

3-Phenylpropionic acid (2) is an intermediate for the anti-aids drag Indinavir. The one step conversion of cinnamaldehyde (4) into 2 was attempted using homogeneous ruthenium catalysts. Use of [H₂Ru(Ph₃P)₄] induced mainly decarbonylation of 4 to give styrene. Use of RuCl₃/PCy₃ gave a mixture of 2 and cinnamic acid (3). Performing the same reaction in methanol, instead of water/dimethoxyethane mixtures afforded methyl 3-phenylpropionate in 70% yield.