Enantioselective total syntheses of (−)-mitragynine, (−)-quinine and (+)-quinidine enabled by Ir-catalysed asymmetric hydrogenation of all-carbon tetrasubstituted cycloalkenes

Syntheses of (−)-mitragynine, (−)-quinine and (+)-quinidine are reported based on Ir-catalysed asymmetric hydrogenation of tetrasubstituted α-acylpyrazole-β-alkyl cycloalkenes to construct piperidine rings bearing 1,2-contiguous cis -stereocenters in high yields and excellent enantioselectivities.