Asymmetric Umpolung (3+2) Cycloadditions of Iminoesters with α,β-Unsaturated-2-acyl Imidazoles for the Synthesis of Substituted Pyrrolidines.
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DOI: 10.1021/acs.orglett.2c01438
Abstract: An enantioselective (3+2) cycloaddition reaction of iminoesters occurring with opposite regioselectivity is reported. This reaction provides chiral polysubstituted pyrrolidines with high enantioselectivities (up to 97%), diastereoselectivities (>20:1), and yields (up to 99%). Interestingly, changing the… read more here.
Keywords: iminoesters unsaturated; asymmetric umpolung; cycloadditions iminoesters; acyl imidazoles ... See more keywords
Formal [3 + 4] Annulation of α,β-Unsaturated Acyl Azoliums: Access to Enantioenriched N-H-Free 1,5-Benzothiazepines.
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DOI: 10.1021/acs.orglett.7b01457
Abstract: An unprecedented formal [3 + 4] annulation of α,β-unsaturated acyl azoliums with 2-aminobenzenethiols has been utilized to synthesize enantioenriched N-H-free 1,5-benzothiazepines, which are recognized as privileged structures in numerous biologically active scaffolds. This protocol offers… read more here.
Keywords: acyl azoliums; unsaturated acyl; enantioenriched free; formal annulation ... See more keywords
Chiral-at-Metal Rh(III) Complex-Catalyzed Michael Addition of Pyrazolones with α,β-Unsaturated 2-Acyl Imidazoles.
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DOI: 10.1021/acs.orglett.8b00040
Abstract: An efficient enantioselective conjugate addition of pyrazolones with α,β-unsaturated 2-acyl imidazoles catalyzed by chiral-at-metal rhodium complex is reported. The corresponding adducts were obtained in good yields (85%-96%) with excellent enantioselectivities (up to >99%). This protocol… read more here.
Keywords: pyrazolones unsaturated; unsaturated acyl; acyl imidazoles; chiral metal ... See more keywords
Enantioselective conjugate addition of hydroxylamines to α,β-unsaturated 2-acyl imidazoles catalyzed by a chiral-at-metal Rh(III) complex
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DOI: 10.1039/c6qo00865h
Abstract: A catalytic enantioselective hydroxyamination of α,β-unsaturated 2-acyl imidazoles with N-protected hydroxyl amines catalyzed by a chiral-at-metal Rh(III) complex (0.5–2 mol%) has been developed. The approach affords valuable N-Boc protected β-amino acid derivatives in moderate to… read more here.
Keywords: unsaturated acyl; catalyzed chiral; acyl imidazoles; chiral metal ... See more keywords
Stereoselective organocatalytic sulfa-Michael reactions of aryl substituted α,β-unsaturated N-acyl pyrazoles
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DOI: 10.1039/c8qo00357b
Abstract: The asymmetric Michael addition of aryl thiols and thioacetic acid to challenging β- or α,β-aryl substituted α,β-unsaturated N-acyl pyrazoles catalysed by bifunctional organocatalysts has been investigated. The corresponding sulfide derivatives are obtained under mild and… read more here.
Keywords: unsaturated acyl; aryl substituted; michael; acyl pyrazoles ... See more keywords