3-Nitro-3,4-dihydrocoumarins: valuable precursors for the synthesis of enantiomerically enriched masked quaternary α-amino acid derivatives with a 3,4-dihydrocoumarin scaffold?

Organic & Biomolecular Chemistry Pub Date: 2019-10-24 DOI: 10.1039/C9OB02089F

Abstract

A bifunctional squaramide catalyzed enantioselective formal [2 + 4] annulation reaction with 3-nitro-3,4-dihydrocoumarins and ortho-quinone methide has been developed. Novel chiral masked quaternary α-amino acid derivatives with a 3,4-dihydrocoumarin scaffold are obtained in a highly stereocontrolled manner. Representative transformation of the annulation product to a biologically important quaternary α-amino acid derivative is achieved without any appreciable loss in the diastereo- and enantioselectivity.

Graphical abstract: 3-Nitro-3,4-dihydrocoumarins: valuable precursors for the synthesis of enantiomerically enriched masked quaternary α-amino acid derivatives with a 3,4-dihydrocoumarin scaffold
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