A novel design of roof-shaped anthracene-fused chiral prolines as organocatalysts for asymmetric Mannich reactions

Abstract

A new class of artificial anthracene-fused chiral proline catalysts has been synthesized from the Diels–Alder adduct of anthracene and maleic anhydride via lithiation/carboxylation of 6 as a key step. Chiral resolution of racemic amino acids was carried out through the formation of diastereomeric esters with (−)-menthol. The absolute configuration of the chiral amino acid was determined by X-ray crystallographic analysis. The utility of the catalyst was confirmed by effecting asymmetric three-component Mannich reactions between aldehyde, ketone, and amine (yield up to 76%, ee up to 90%).