Tripeptide Organocatalysts for Stereoselective Conjugate Addition Reactions with N‐Heterocyclic Substituents

Abstract N‐heterocyclic moieties are abundant among pharmaceuticals and agrochemicals, but a challenge for metalorganic and organocatalytic transformations. We present tripeptides of the type H‐Pro‐Pro‐Xaa as catalysts for stereoselective conjugate addition reactions between N‐heterocyclic substituted aldehydes and electrophiles. Alkyl substituents at the N‐terminal proline, the reactive site, were crucial for high chemo‐ and stereoselectivity. Different N‐heterocyclic moieties, even at both reaction partners, were readily tolerated and products were obtained in yields of 61–95% and enantioselectivities of up to 98% ee. magnified image