Recent developments in the homogeneous hydrogenation of carboxylic acid esters

A concise review highlighting the more successful catalyst designs used in homogeneous hydrogenation of carboxylic acid esters is presented. An interesting range of multidentate and heterobidentate ligands have been employed, generally as complexes of ruthenium, but the use of osmium and iridium catalysts is also noted. An estimate of the relative reactivity of the catalysts is made based on average turnover frequencies for comparable substrates. Issues relating to substrate scope are also discussed.