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.

A versatile nitro-Mannich/lactamisation cascade for the direct stereoselective synthesis of heavily decorated 5-nitropiperidin-2-ones and related heterocycles has been developed. A highly enantioenriched substituted 5-nitropiperidin-2-one was synthesised in a four component one-pot reaction combining an enantioselective organocatalytic Michael addition with the diastereoselective nitro-Mannich/...

PEG-embedded potassium tribromide ([K(+)PEG]Br(3) (-)) was found to be an efficient and recyclable catalyst for the synthesis of functionalized piperidines in high yields in a one step, three component coupling between aldehyde, amine and β-keto ester. At the end of the reaction the [K(+)PEG]Br(3) (-) was readily regenerated from the reaction mixture by treating the residue containing [K(+)PEG]...

Utilising the propensity of the 2-furanyl group to facilitate equilibration of an adjacent tosylamide chiral centre, a diastereoselective route to 2,6-syn-piperidines was developed that proceeds with high levels of thermodynamic stereocontrol. X-ray crystallography structures suggest that, as seen in similar systems, pseudo-allylic strain between the N-tosyl group and the substituents at the 2 ...

A very efficient route to the diastereoselective synthesis of polyhydroxy pyrrolidines, piperidines and azepanes from an aldehyde derivative of ribose is reported. Asymmetric α-amination of aldehydes using proline catalysed hydrazination is the key step in the synthesis. The method utilizes the stereocenters present in ribose and the extra carbon atoms present in the target molecules are incorp...

Starting from nitroarenes, under hydrosilylation conditions, using a well-defined N-heterocyclic carbene iron(0) catalyst, (IMes)Fe(CO)4, the corresponding aniline derivatives were produced in 61–92% isolated yields. More impressively, selective synthesis of cyclic amines such as pyrrolidines, piperidines and azepanes conducted levulinic acid, 1,5- 1,6-keto acids, respectively. The sequential p...

The Prins reaction was investigated using BF₃.OEt₂ as a Lewis acid. It has been recently demonstrated, that if BF₃.OEt₂ is used in stoichiometric amounts then these reactions generate fluorinated products where the BF₃.OEt₂ contributes fluoride ion to quench the intermediate carbocations. In this study oxa- and aza-Prins reactions for the synthesis of 4-fluoro-pyrans and -piperidines were inves...