Organocatalytic regio-and stereoselective synthesis of chiral tetrasubstituted α-amino allenoates by γ-additions of β,γ-alkynylα-imino esters with pyrazolones

Abstract

Herein, we report a bis-dihydroquinine-catalyzed asymmetric nucleophilic addition of pyrazolones to β,γ-alkynyl-α-imino esters. This method enables the efficient synthesis of allenylpyrazolone derivatives featuring adjacent quaternary stereocenters and axially chiral tetrasubstituted allene motifs in high yields with excellent regio-, diastereo-, and enantioselectivities.