Supported organocatalysis as a greener alternative in the production of fine chemicals

Organocatalysis is a useful tool for organic synthesis and plays a key role in many sectors of the chemical business, most notably in the pharmaceutical industry and drug discovery, as well as for the production of many modern commodities in the food, agrochemical and cosmetic businesses. Since the use of potentially toxic metal species is intrinsically avoided, organocatalysis can lead to more sustainable processes. The majority of organocatalytic processes currently being investigated are run as homogeneous catalytic reactions, whereby the catalyst is dissolved in the reactive mixture. The major drawback of this approach is in the laborious, expensive and energy-intensive procedures needed to separate the catalyst from the reaction products which, in many cases, is unfeasible or may lead to catalyst degradation with consequent waste of valuable material, with impact on process sustainability. In this work we show a promising way to carry out organocatalytic processes by adopting an approach whereby the organocatalyst is immobilised onto a solid support, hence made insoluble, which has advantages both in terms of avoiding energy-intensive distillation procedures as well as enabling catalyst recycling and reuse and potentially use of such materials for fixed-bed continuous processes. We show that in some cases the activity of the immobilised organocatalyst is comparable to that of the homogeneous counterpart. The results reported here have important implication for the development of greener and more sustainable routes for the production of fine and specialty chemicals, which may pave the way to new developments, especially in the pharmaceutical industry.