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Regioselective catalytic transformations using supramolecular directing groups are increasingly popular as it allows for control over challenging reactions that may otherwise be impossible. In most examples the reactive group and the directing group are close to each other and/or the linker between the directing group is very rigid. Achieving control over the regioselectivity using a remote directing group with a flexible linker is significantly more challenging due to the large conformational freedom of such substrates. Herein, we report the redesign of a supramolecular Rh-bisphosphite hydroformylation catalyst containing a neutral carboxylate receptor (DIM pocket) with a larger distance between the phosphite metal binding moieties and the DIM pocket. For the first time regioselective conversion of internal and terminal alkenes containing a remote carboxylate directing group is demonstrated. For carboxylate substrates that possess an internal double bond at the Δ-9 position regioselectivity is observed. As such, the catalyst was used to hydroformylate natural monounsaturated fatty acids (MUFAs) in a regioselective fashion, forming of an excess of the 10-formyl product (10-formyl/9-formyl product ratio of 2.51), which is the first report of a regioselective hydroformylation reaction of such substrates., (© 2020 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Herein, we report a supramolecular rhodium complex that can form dimeric or monomeric Rh-species catalytically active in hydroformylation, depending on the binding of effectors within the integrated DIM-receptor. X-ray crystal structures, in situ (high-pressure (HP)) spectroscopy studies, and molecular modelling studies show that in the absence of effectors, the preferred Rh-species formed is the dimer, of which two ligands coordinate to two rhodium metals. Importantly, upon binding guest molecules, -effectors-, to the DIM-receptor under hydroformylation conditions, the monomeric Rh-active species is formed, as evidenced by a combination of in situ HP NMR and IR spectroscopy studies and molecular modelling. As the monomeric complex has different catalytic properties from the dimeric complex, we effectively generate a catalytic system of which the properties respond to the presence of effectors, reminiscent of how the properties of proteins are regulated in nature. Indeed, catalytic and kinetic experiments show that both the selectivity and activity of this supramolecular catalytic system can be influenced in the hydroformylation of 1-octene using acetate as an effector that shift the equilibrium from the dimeric to monomeric species.