1,721,016 research outputs found
Asymmetric Construction of γ-lactams Displaying All-carbon, Aza-, Thia- and Oxa-quaternary Chiral Centers
No full textgamma-lactams, bearing one or more chiral centers are important scaffolds and widely occur in many natural and synthetic products of clinical interest, but the synthetic approaches mainly focus on the preparation of rings that display trisubstituted carbons, whereas only a few examples concern the construction of chiral gamma-lactams that display tetrasubstituted carbon atoms. However, in recent years, the broad potential of these latter compounds was recognized and deserved high interest, owing to their complex three-dimensional features and structural rigidity. Thus, several efforts were engaged in the pursuit of new synthetic strategies towards gamma-lactam rings that contain tetrasubstituted carbons that pose a particular challenge, and the present review gathers advances reported since 2015 about the enantioselective preparation of these molecules, carried out to exploit both internal and external asymmetric induction
Recent Advances in Chemistry of γ-Lactams: Part I. Synthesis Starting from Acyclic or Cyclic Precursors
No full textγ-Lactams (pyrrolidin-2-ones) and products containing the γ-lactam core are important synthetic targets and often display interesting biological activities, so that the development of improved synthetic methodologies for their preparation has become the objective of many synthetic chemists. This review is presented in two parts: Part I highlights efficient synthetic strategies (issued between 2001 and 2013), which are classified according to the last step of the lactam ring formation, starting from acyclic or cyclic precursors, whereas Part II dealt with functionalization of γ-lactam ring via C-C or C-Heteroatom bond formation. Enantioselective synthesis is thoroughly emphasized in both sections, also exploiting catalytic systems, since pure enantiomeric derivatives are important for biological testing
Synthesis of Enantiomerically Pure 3-Amino-2-methylenealkanoates (Aza-Morita–Baylis–Hillman Adducts) Mediated by Cinchona Alkaloids
No full textChiral Nonaromatic Nitrogen-Heterocycles by Asymmetric Intramolecular Haloamination and Haloamidation
Full text linkThis review deals with the functionalization of double bonds carried out in the presence of a chiral catalyst exploiting the intramolecular attack to haliranium ions by nucleophilic nitrogen of amides or carbamates prepared from achiral aminoalkenes, and the C–N bonds formation leads to highly enantioenriched nonaromatic heterocycles. A range of protocols are reported, emphasizing the synthesis of many natural and biologically active products of pharmacological interest prepared according to this methodolog
Stereoselective iodocyclisation of 3-acylamino-2-methylene alkanoates: a computational insight
No full textStereoselective alkylation of chiral pyrrolidin-2-ones leading to novel conformationally restricted analogues of 3-methylaspartic acid: a computational investigation
No full textAcidity effect on the cleavage of ether function intramolecularly assisted by the amide group. Part 5.
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Iodociclizzazione stereoselettiva di 3-acilammino-2-metilene alcanoati: sintesi di analoghi dell’N-benzoil-syn-fenilisoserina
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