| Article ID | Journal | Published Year | Pages | File Type |
|---|---|---|---|---|
| 1347118 | Tetrahedron: Asymmetry | 2014 | 6 Pages |
The cinchona-based primary amine-catalyzed enantioselective aza-Michael reaction of α,β-unsaturated aldehydes with 4,5-dihalo-1H-pyrrole-2-carbonitriles as the N-centered heteroaromatic nucleophile, followed by chemoselective reduction provided the corresponding chiral aza-Michael products in good yields and with excellent enantioselectivities (90–97% ee).
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(S)-2-(2,3-Dibromo-5-cyano-1H-pyrrol-1-yl)-4-hydroxybutyl benzoateC16H14Br2N2O390% ee[α]D22 = +6.9 (c 1, CH3OH)Source of chirality: chiral organocatalystAbsolute configuration: (S)
(S)-4,5-Dibromo-1-[1-(tert-butyldiphenylsilyloxy)-4-hydroxybutan-2-yl]-1H-pyrrole-2-carbonitrileC25H28Br2N2O2Si94% ee[α]D24 = +20.4 (c 1, CH3OH)Source of chirality: chiral organocatalystAbsolute configuration: (S)
(S)-1-[1-(Benzyloxy)-4-hydroxybutan-2-yl]-4,5-dibromo-1H-pyrrole-2-carbonitrileC16H16Br2N2O290% ee[α]D24 = +3.2 (c 1, CHCl3)Source of chirality: chiral organocatalystAbsolute configuration: (S)
(S)-1-[1-[(Benzyloxycarbonyl)(tert-butoxycarbonyl)amino]-4-hydroxybutan-2-yl]-4,5-dibromo-1H-pyrrole-2-carbonitrileC22H25Br2N3O595% ee[α]D25 = +61.2 (c 1, CHCl3)Source of chirality: chiral organocatalystAbsolute configuration: (S)
(R)-4,5-Dibromo-1-(1-hydroxyhexan-3-yl)-1H-pyrrole-2-carbonitrileC11H14Br2N2O92% ee[α]D25 = −12.2 (c 1, CHCl3)Source of chirality: chiral organocatalystAbsolute configuration: (R)
(R)-4,5-Dibromo-1-(4-hydroxy-1-phenylbutan-2-yl)-1H-pyrrole-2-carbonitrileC15H14Br2N2O91% ee[α]D25 = +58.0 (c 1, CHCl3)Source of chirality: chiral organocatalystAbsolute configuration: (R)
(S)-2-(2-Bromo-3-chloro-5-cyano-1H-pyrrol-1-yl)-4-hydroxybutyl benzoateC16H14BrClN2O393% ee[α]D22 = −2.8 (c 1, CHCl3)Source of chirality: chiral organocatalystAbsolute configuration: (S)
(S)-1-[1-[(Benzyloxycarbonyl)(tert-butoxycarbonyl)amino]-4-hydroxybutan-2-yl]-5-bromo-4-chloro-1H-pyrrole-2-carbonitrileC22H25BrClN3O591% ee[α]D22 = +70.8 (c 1, CHCl3)Source of chirality: chiral organocatalystAbsolute configuration: (S)
(R)-5-Bromo-4-chloro-1-(1-hydroxyhexan-3-yl)-1H-pyrrole-2-carbonitrileC11H14BrClN2O91% ee[α]D20 = −13.2 (c 1, CHCl3)Source of chirality: chiral organocatalystAbsolute configuration: (R)
(R)-5-Bromo-4-chloro-1-(4-hydroxy-1-phenylbutan-2-yl)-1H-pyrrole-2-carbonitrileC15H14BrClN2O94% ee[α]D20 = +67.0 (c 1, CHCl3)Source of chirality: chiral organocatalystAbsolute configuration: (R)
(S)-1-[1-(Benzyloxy)-4-hydroxybutan-2-yl]-4-bromo-1H-pyrrole-2-carbonitrileC16H17BrN2O297% ee[α]D22 = −28.1 (c 1, CHCl3)Source of chirality: chiral organocatalystAbsolute configuration: (S)
(S)-1-[1-[(Benzyloxycarbonyl)(tert-butoxycarbonyl)amino]-4-hydroxybutan-2-yl]-4-bromo-1H-pyrrole-2-carbonitrileC22H26BrN3O593% ee[α]D22 = +44.7 (c 1, CHCl3)Source of chirality: chiral organocatalystAbsolute configuration: (S)
(R)-4-Bromo-1-(4-hydroxy-1-phenylbutan-2-yl)-1H-pyrrole-2-carbonitrileC15H15BrN2O95% ee[α]D22 = +74.3 (c 1, CHCl3)Source of chirality: chiral organocatalystAbsolute configuration: (R)
(S)-1-[1-(Benzyloxy)-4-hydroxybutan-2-yl]-4-bromo-5-iodo-1H-pyrrole-2-carbonitrileC16H16BrN2O2I96% ee[α]D20 = −4.4 (c 1, CHCl3)Source of chirality: chiral organocatalystAbsolute configuration: (S)
(S)-1-[1-[(Benzyloxycarbonyl)(tert-butoxycarbonyl)amino]-4-hydroxybutan-2-yl]-4-bromo-5-iodo-1H-pyrrole-2-carbonitrileC22H25BrN3O5I93% ee[α]D20 = +53.2 (c 1, CHCl3)Source of chirality: chiral organocatalystAbsolute configuration: (S)
(R)-4-Bromo-1-(4-hydroxy-1-phenylbutan-2-yl)-5-iodo-1H-pyrrole-2-carbonitrileC15H14BrN2OI94% ee[α]D22 = +45.1 (c 1, CHCl3)Source of chirality: chiral organocatalystAbsolute configuration: (R)
