Stereoselective construction of quaternary carbon centers by three component coupling reactions
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چکیده
منابع مشابه
Construction of quaternary stereogenic carbon centers through copper-catalyzed enantioselective allylic cross-coupling with alkylboranes.
A combination of an in situ generated chiral Cu(I) /DTBM-MeO-BIPHEP catalyst system and EtOK enabled the enantioselective SN 2'-type allylic cross-coupling between alkylborane reagents and γ,γ-disubstituted primary allyl chlorides with enantiocontrol at a useful level. The reaction generates a stereogenic quaternary carbon center having three sp(3) -alkyl groups and a vinyl group. This protocol...
متن کاملEnantioselective construction of cyclic quaternary centers: (-)-mesembrine.
The preparation of the crystalline amide 2 is reported. Conjugate addition to 2 proceeded with the expected high diastereocontrol to give 3. This set the stage for subsequent intramolecular alkylidene C-H insertion to give, after ozonolysis and aldol condensation, (-)-mesembrine 1. Amide 2 should be a useful chiron for the enantioselective construction of cyclic quaternary centers.
متن کاملCatalytic Enantioselective Construction of All-Carbon Quaternary Stereocenters Catalytic Enantioselective Construction of All-Carbon Quaternary Stereocenters
SYNTHESIS 2006, No. 3, pp 0369–0396xx.xx.2006 Advanced online publication: 13.01.2006 DOI: 10.1055/s-2006-926302; Art ID: E14205SS © Georg Thieme Verlag Stuttgart · New York Abstract: Catalytic enantioselective construction of all-carbon quaternary stereocenters, i.e. carbon atoms bearing four different carbon substituents, poses a particular challenge in organic synthesis. This review gives a ...
متن کاملEnantioselective construction of quaternary carbon centre catalysed by bifunctional organocatalyst.
The bifunctional thiourea-tertiary amine derivatives of simple chiral diamines serve as highly enantioselective catalysts for the Michael addition of alpha-substituted cyanoacetates to vinyl sulfones, giving an efficient protocol for the construction of an all-carbon substituted quaternary stereocentre.
متن کاملLigand-Enabled γ-C–H Olefination and Carbonylation: Construction of β-Quaternary Carbon Centers
Monoselective γ-C-H olefination and carbonylation of aliphatic acids has been accomplished by using a combination of a quinoline-based ligand and a weakly coordinating amide directing group. The reaction provides a new route for constructing richly functionalized all-carbon quaternary carbon centers at the β-position of aliphatic acids.
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ژورنال
عنوان ژورنال: Tetrahedron Letters
سال: 2000
ISSN: 0040-4039
DOI: 10.1016/s0040-4039(00)01602-6