[Co(TPP)]‐Catalyzed Formation of Substituted Piperidines

Asymmetric synthesis of substituted NH-piperidines from chiral amines.

Previously, we reported an efficient asymmetric synthesis of substituted piperidines through an exocyclic chirality induced nitroalkene/amine/enone (NAE) condensation reaction. An effective protecting group strategy was developed herein to achieve enantiopure piperidines (yields up to 92%) with complete chirality retention (ee > 95%). A simple derivatization of the obtained piperidines gave thi...

Enantioselective synthesis of 2-substituted and 3-substituted piperidines through a bromoaminocyclization process.

A catalytic enantioselective bromocyclization of olefinic amides using amino-thiocarbamates as the catalysts has been developed. The resulting enantioenriched 2-substituted 3-bromopiperidines can readily be transformed to 3-substituted piperidines through a silver salt-mediated rearrangement. This process has been applied to the synthesis of a dopaminergic drug, Preclamol.

SbCl3 as an Efficient Catalyst for the One-pot Synthesis of Highly Substituted Piperidines

Highly substituted piperidines were synthesized via the condensation of aromatic aldehydes and aromatic amines with β-ketoesters in the presence of antimony(III) chloride at ambient condition. This reaction has any advantages such as easy work-up, clean procedure, and good yields.

Unstabilized azomethine ylides for the stereoselective synthesis of substituted piperidines, tropanes, and azabicyclo[3.1.0] systems.

Acid treatment of densely substituted 2-silyl-1,2-dihydropyridines provides a new and convenient entry to reactive azomethine ylides that can (1) be protonated and reduced with high stereoselectivity to give piperidines, (2) participate in [3 + 2] dipolar cycloaddition to give tropanes, and (3) undergo a Nazarov-like 6-π electrocyclization that upon reduction give 2-azabicyclo[3.1.0] systems.

Reaction Between Grignard Reagents and Heterocyclic N-oxides Synthesis of Substituted Pyridines, Piperidines and Piperazines