Organocatalytic and Stereoselective [3 + 2] Cycloadditions of Azomethine Imines with α,β‐Unsaturated Aldehydes.

Abstract

Pyrazole derivatives R 0180 Organocatalytic and Stereoselective [3 + 2] Cycloadditions of Azomethine Imines with α,β-Unsaturated Aldehydes. -A new route towards tetrahydropyrazolo[1,2-a]pyrazole derivatives possessing multiple contiguous chiral centers is presented. -(CHEN, W.; YUAN, X.-H.; LI, R.; DU, W.; WU, Y.; DING, L.-S.; CHEN*, Y.-C.; Adv.

Recent Advances of Catalytic Asymmetric 1,3-Dipolar Cycloadditions

“…Iminium catalysis was applied in the catalytic asymmetric 1,3-DC of N,N′-cyclic azomethine imines and enals by Chen and co-workers (Scheme 58). 88 By use of diarylprolinol 74 and trifluoroacetic acid, exoselective cyclization occurred smoothly to give 120 with high enantioselectivities. MacMillan's chiral imidazolidinone catalyst provided the cycloadduct as a 1:1 mixture of diastereomers except for the reaction of aliphatic azomethine imine in which high exo-and enantioselectivities were attained.…”

“…Iminium catalysis was applied in the catalytic asymmetric 1,3-DC of N , N ′-cyclic azomethine imines and enals by Chen and co-workers (Scheme ) . By use of diarylprolinol 74 and trifluoroacetic acid, exoselective cyclization occurred smoothly to give 120 with high enantioselectivities.…”