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...

Chiral aminoalkyl epoxyaziridine 1 is synthesized in high yield and diastereoselectivity from L-serine. Ring opening of epoxyaziridine 1 with primary amines is carried out with total chemo- and regioselectivity, affording chiral polyfunctionalized piperidines 8. The structure of these trisubstituted piperidines is established by NMR studies.

Iridium-catalyzed asymmetric hydrogenation of N-alkyl-2-alkylpyridinium salts provided 2-aryl-substituted piperidines with high levels of enantioselectivity. Simple benzyl and other alkyl groups successfully activated the challenging pyridine substrates toward hydrogenation. The use of the unusual chiral-phosphole-based MP(2) -SEGPHOS was the key to the success of this approach which provides a...

The chiral base n-BuLi/(-)-sparteine or n-BuLi/(+)-sparteine surrogate promotes kinetic resolution of N-Boc-2-arylpiperidines by asymmetric deprotonation. The enantioenriched starting material was recovered with yields 39-48% and ers up to 97 : 3. On lithiation then electrophilic quench, 2,2-disubstituted piperidines were obtained with excellent yields and enantioselectivities.

The alkaloid chemistry of the venom of hybrid fire ant, Solenopsis richteri × Solenopsis invicta, was investigated using silica gel chromatography and GC-MS techniques. In addition to most cis alkaloids of parental species, S. richteri Forel and S. invicta Buren, the cis alkaloid fraction of the body extract of hybrid fire ants also contains five significant new alkaloids. Hydrogenation of the ...

An efficient green chemistry approach to the synthesis of N-substituted piperidones and piperidines was developed and applied to the synthesis of 1-(2-pyridinylmethyl)-piperidin-4-one, 1, a key starting material for the synthesis of LY317615, an antiangiogenic agent currently under development at Eli Lilly and Company (Chart 1).(1) The general utility of this methodology, which presents signifi...

FeCl3.6H2O was used as an efficient catalyst for the synthesis of highly functionalized piperidines via a one-pot five-component reaction of aromatic amines, aromatic aldehydes and β-keto esters in EtOH at room temperature. The remarkable advantages offered by this method are good yields, simple procedure, short reaction times, no need to column chromatography and easy work-up. The structures o...

FeCl3.6H2O was used as an efficient catalyst for the synthesis of highly functionalized piperidines via a one-pot five-component reaction of aromatic amines, aromatic aldehydes and β-keto esters in EtOH at room temperature. The remarkable advantages offered by this method are good yields, simple procedure, short reaction times, no need to column chromatography and easy work-up. The structures o...

fecl3.6h2o was used as an efficient catalyst for the synthesis of highly functionalized piperidines via a one-pot five-component reaction of aromatic amines, aromatic aldehydes and β-keto esters in etoh at room temperature. the remarkable advantages offered by this method are good yields, simple procedure, short reaction times, no need to column chromatography and easy work-up. the structures o...