Polystyrene-supported organocatalysts for α-selenenylation and Michael reactions: A common post-modification approach for catalytic differentiation

Three different resin-supported catalysts have been prepared by using the well established post-modification approach by means of thiol-ene coupling reaction. Two catalysts were tested for the first time in the asymmetric α-selenenylation of propanal, while the third catalyst was used in the Michael addition reaction. While the preliminary results are not encouraging in the case of supported Jørgensen’ catalyst, interesting data have been collected with both for the supported MacMillan and prolyl-prolinol catalysts. In fact, these catalysts displayed good activity and selectivity. A reversed enantioselectivity in the α-selenenylation was observed by changing the polarity of the solvent. Finally, these materials were easily recovered, and used four and five times, respectively.

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► Polystyrene supported Jørgensen catalyst synthesis.
► Polystyrene supported MacMillan catalyst synthesis.
► Polystyrene supported prolyl-prolinol catalyst synthesis.
► Asymmetric alfa-selenenylation of propanal.
► Asymmetric Michael addition of aldehydes to nitrostyrene.