Solvent-dependent enantioswitching in the Michael addition of α,α-disubstituted aldehydes to maleimides organocatalyzed by mono-N-Boc-protected cyclohexa-1,2-diamines
نویسندگان
چکیده
منابع مشابه
Solvent-Dependent Enantioswitching in the Michael Addition of α,α-Disubstituted Aldehydes to Maleimides Organocatalyzed by Mono-N-Boc-Protected Cyclohexa-1,2-Diamines
Enantiomerically pure mono-N-Boc-protected trans-cyclohexane-1,2-diamines are used as organocatalysts for the enantioselective conjugate addition of α,α-disubstituted aldehydes to maleimides. Using a single enantiomer of the organocatalyst, both enantiomeric forms of the resulting Michael adducts bearing a new quaternary stereocenter are obtained in high yields, only by changing the reaction so...
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Primary amine-salicylamides derived from chiral trans-cyclohexane-1,2-diamines are used as organocatalysts for the enantioselective conjugate addition of α,α-disubstituted aldehydes to arylated and heteroarylated nitroalkenes. The reaction is performed in the presence of 4-dimethylaminopyridine as an additive in dichloromethane as a solvent at room temperature. The corresponding enantioenriched...
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The first highly efficient Michael addition of challenging α,α-disubstituted aldehydes to maleimides catalyzed by a simple bifunctional primary amine thiourea catalyst/benzoic acid system has been successfully developed to generate quaternary carbon centers in high yields (up to 99%) with excellent enantioselectivities (91-99%).
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The application of six novel α,β-dipeptides as chiral organocatalysts in the asymmetric Michael addition reaction between enolizable aldehydes and N-arylmaleimides or nitroolefins is described. With N-arylmaleimides as substrates, the best results were achieved with dipeptide 2 as a catalyst in the presence of aq. NaOH. Whereas dipeptides 4 and 6 in conjunction with 4-dimethylaminopyridine (DMA...
متن کاملOrganocatalytic enantioselective conjugate addition of aldehydes to maleimides.
The highly enantioselective direct organocatalytic conjugate addition of aldehydes to maleimides is presented.
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ژورنال
عنوان ژورنال: Tetrahedron: Asymmetry
سال: 2014
ISSN: 0957-4166
DOI: 10.1016/j.tetasy.2014.06.014