Reductive hydroformylation of methyl 10-undecenoate catalyzed by a rhodium/trialkylamine combination associated with silica: a new step towards a simple, robust and recyclable catalytic system

Abstract

The reductive hydroformylation of methyl 10-undecenoate catalysed by a rhodium/amine system was investigated in the presence of silica. The addition of silica enabled the immobilisation of over 95% of the catalyst, allowing more than 10 consecutive recycling cycles with minimal rhodium loss. Under these conditions, the reaction delivers excellent yields of the corresponding alcohols. Efficient immobilisation relies on the use of weakly hindered amines and can be readily achieved using inexpensive, commercially available trialkylamines such as triethylamine. Moreover, the reaction can be carried out in environmentally benign solvents or under neat conditions without compromising efficiency. The underlying mechanism involves the formation of polar rhodium species that strongly adsorb onto the silica surface, accounting for the unexpected robustness and simplicity of the system.