Novel Octapeptide as an Asymmetric Catalyst for Michael Reaction in Aqueous Media

Abstract

In this work, three forms of a novel octapeptide have been evaluated as asymmetric catalysts for the Michael reaction. Low quantity catalyst loading, ecofriendly solvents, and reusability of organocatalyst successfully applied to attain excellent yields and moderate enantioselectivities in the Michael reaction.

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GRAPHICAL ABSTRACT

Keywords:

• Asymmetric
• enantioselectivities
• Michael reaction
• octapeptide
• organocatalyst
• reusablity

Notes

^a Reaction were performed with aldehydes or ketones (2eq) and nitroolefins (1eq), solvents (0.5 ml:0.5 ml), NMM (1 drop to adjust pH = 5–5.5), at RT.

^b Isolated yield of mixture of syn/anti based on nitrostyrene. Diastereomeric ratio, determined by ¹H NMR.

^c Enantiomeric excess, determined by chiral-phase HPLC analysis.

^d Diisopropylethylamine (to adjust pH = 5–5.5).