A comparison of homogeneous and biphasic hydrogenation systems of macrocyclic lactones with in situ formed rhodium complexes

Homogeneous and biphasic hydrogenation of avermectins catalyzed by rhodium complexes in situ formed from [RhCl(COD)]₂ and triphenylphosphine or sulphonated arylphosphines, respectively, was studied under mild reaction conditions. Effects of adding TBAB and bis-QACs as phase transfer agents, Tween? 80 as non-ionic surfactant, β-cyclodextrin as inverse phase-transfer agent, and triphenylphosphine as co-ligand, are reported for the biphasic system.