Asymmetric Electrophilic α-Amidoalkylation, 9:1Highly Stereoselective Syntheses of 2-Substituted Piperidines
نویسندگان
چکیده
منابع مشابه
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...
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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.
متن کاملHemiaminals as substrates for sulfur ylides: direct asymmetric syntheses of functionalised pyrrolidines and piperidines.
Phenyl stabilised chiral sulfur ylides react with five-membered-ring hemiaminals to give functionalised pyrrolidines directly with high enantioselectivity. The reaction can be diverted to give piperidines instead by isolation of the intermediate epoxide and treatment with TMSOTf.
متن کاملEnantioselective 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.
متن کاملStereoselective syntheses of fluorescent non-natural aromatic amino acids based on asymmetric Michael additions.
Four fluorescent non-natural aromatic amino acids have been synthesized based on a key stereoselective Michael addition reaction. S-1-phenylethylamine was employed as both the source of amine and the stereoselectivity controller. The overall yields were moderate (30-50%). Fluorescent properties of some of the fluorophores were also investigated. It was found that compounds with a dimethylamino ...
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ژورنال
عنوان ژورنال: Synlett
سال: 1991
ISSN: 0936-5214,1437-2096
DOI: 10.1055/s-1991-20880