| Article ID | Journal | Published Year | Pages | File Type |
|---|---|---|---|---|
| 1345766 | Tetrahedron: Asymmetry | 2014 | 10 Pages |
The In and Zn-mediated allylation of substituted pyrazol-4-yl derived (R)-N-tert-butanesulfinyl imines proceeds with high diastereoselectivity depending on the conditions and additives (up to 99.4% de). Thus, the synthesized diastereomeric homoallylsulfinamides were isolated and characterized as pure diastereomers, which were then converted into the corresponding pyrazol-4-yl-derived N-Boc-homoallylamines via consecutive treatment with HCl and Boc2O. The latter were then subjected to a sequence of reactions: cyclobromocarbamation with NBS and enolate–isocyanate rearrangement with tBuOK to give novel enantiomerically pure (S)-6-(pyrazol-4-yl)-piperidine-2,4-diones in 88–96% yield. The absolute configurations of the allylation products were assigned by X-ray single crystal analysis of the intermediate bromomethylurethanes.
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(R)-2-Methyl-N-[(1-methyl-1H-pyrazol-4-yl)methylidene]-2-propanesulfinamideC9H15N3OS[α]D25 = −130.7 (c 1, CHCl3)Source of chirality: Ellman’s auxiliaryAbsolute configuration: (RS)
(R)-N-[(1-Ethyl-3-methyl-1H-pyrazol-4-yl)methylidene]-2-methyl-2-propanesulfinamideC11H19N3OS[α]D25 = −93.7 (c 1, CHCl3)Source of chirality: Ellman’s auxiliaryAbsolute configuration: (RS)
(R)-N-[(1-Ethyl-1H-pyrazol-4-yl)methylidene]-2-methyl-2-propanesulfinamideC10H17N3OS[α]D25 = −121.5 (c 1, CHCl3)Source of chirality: Ellman’s auxiliaryAbsolute configuration: (RS)
(R)-2-Methyl-N-[1-(1-methyl-1H-pyrazol-4-yl)ethylidene]-2-propanesulfinamideC10H17N3OS[α]D25 = −73.7 (c 1, CHCl3)Source of chirality: Ellman’s auxiliaryAbsolute configuration: (RS)
(R)-2-Methyl-N-[(1-phenyl-1H-pyrazol-4-yl)methylidene]-2-propanesulfinamideC14H17N3OS[α]D25 = −98.7 (c 1, CHCl3)Source of chirality: Ellman’s auxiliaryAbsolute configuration: (RS)
(R)-N-[(1S)-1-(1-Ethyl-1H-pyrazol-4-yl)-3-butenyl]-2-methyl-2-propanesulfinamideC13H23N3OS[α]D25 = −81.5 (c 1, CHCl3)Source of chirality: Ellman’s auxiliaryAbsolute configuration: (RS,1S)
(R)-N-[(1R)-1-(1-Ethyl-1H-pyrazol-4-yl)-3-butenyl]-2-methyl-2-propanesulfinamideC13H23N3OS[α]D25 = −33.8 (c 1, CHCl3)Source of chirality: Ellman’s auxiliaryAbsolute configuration: (RS,1R)
(R)-2-Methyl-N-[(1S)-1-(1-methyl-1H-pyrazol-4-yl)-3-butenyl]-2-propanesulfinamideC12H21N3OS[α]D25 = −110.2 (c 1, CHCl3)Source of chirality: Ellman’s auxiliaryAbsolute configuration: (RS,1S)
(R)-2-Methyl-N-[(1R)-1-(1-methyl-1H-pyrazol-4-yl)-3-butenyl]-2-propanesulfinamideC12H21N3OS[α]D25 = −40.6 (c 1, CHCl3)Source of chirality: Ellman’s auxiliaryAbsolute configuration: (RS,1R)
(R)-N-[(1S)-1-(1-Ethyl-3-methyl-1H-pyrazol-4-yl)-3-butenyl]-2-methyl-2-propanesulfinamideC14H25N3OS[α]D25 = −107.7 (c 1, CHCl3)Source of chirality: Ellman’s auxiliaryAbsolute configuration: (RS,1S)
(R)-N-[(1R)-1-(1-Ethyl-3-methyl-1H-pyrazol-4-yl)-3-butenyl]-2-methyl-2-propanesulfinamideC14H25N3OS[α]D25 = −63.5 (c 1, CHCl3)Source of chirality: Ellman’s auxiliaryAbsolute configuration: (RS,1R)
(R)-2-Methyl-N-[(1S)-1-(1-phenyl-1H-pyrazol-4-yl)-3-butenyl]-2-propanesulfinamideC17H23N3OS[α]D25 = −100.9 (c 1, CHCl3)Source of chirality: Ellman’s auxiliaryAbsolute configuration: (RS,1S)
(R)-2-Methyl-N-[(1R)-1-(1-phenyl-1H-pyrazol-4-yl)-3-butenyl]-2-propanesulfinamideC17H23N3OS[α]D25 = −30.2 (c 1, CHCl3)Source of chirality: Ellman’s auxiliaryAbsolute configuration: (RS,1R)
(R)-2-Methyl-N-[(1S)-1-methyl-1-(1-methyl-1H-pyrazol-4-yl)-3-butenyl]-2-propanesulfinamideC13H23N3OS[α]D25 = −75.5 (c 1, CHCl3)Source of chirality: Ellman’s auxiliaryAbsolute configuration: (RS,1S)
(S)-tert-Butyl N-[1-(1-ethyl-1H-pyrazol-4-yl)-3-butenyl]carbamateC14H23N3O2[α]D25 = −40.8 (c 1, CHCl3)Source of chirality: Ellman’s auxiliaryAbsolute configuration: (S)
(S)-tert-Butyl N-[1-(1-ethyl-1H-pyrazol-4-yl)-3-butenyl]carbamateC13H21N3O2[α]D25 = −41.2 (c 1, CHCl3)Source of chirality: Ellman’s auxiliaryAbsolute configuration: (S)
(S)-tert-Butyl N-[1-(1-ethyl-3-methyl-1H-pyrazol-4-yl)-3-butenyl]carbamateC15H25N3O2[α]D25 = −39.1 (c 1, CHCl3)Source of chirality: Ellman’s auxiliaryAbsolute configuration: (S)
(S)-tert-Butyl N-[1-(1-phenyl-1H-pyrazol-4-yl)-3-butenyl]carbamateC18H23N3O2[α]D25 = −53.7 (c 1, CHCl3)Source of chirality: Ellman’s auxiliaryAbsolute configuration: (S)
(S)-tert-Butyl N-[1-methyl-1-(1-methyl-1H-pyrazol-4-yl)-3-butenyl]carbamateC14H23N3O2[α]D25 = −21.3 (c 1, CHCl3)Source of chirality: Ellman’s auxiliaryAbsolute configuration: (S)
(4S,6R)-6-(Bromomethyl)-4-(1-ethyl-1H-pyrazol-4-yl)-1,3-oxazinan-2-oneC10H14BrN3O2[α]D25 = +1.6 (c 1, CHCl3)Source of chirality: Ellman’s auxiliaryAbsolute configuration: (4S,6R)
(4S,6R)-6-(Bromomethyl)-4-(1-methyl-1H-pyrazol-4-yl)-1,3-oxazinan-2-oneC9H12BrN3O2[α]D25 = +0.5 (c 1, CHCl3)Source of chirality: Ellman’s auxiliaryAbsolute configuration: (4S,6R)
(4S,6R)-6-(Bromomethyl)-4-(1-phenyl-1H-pyrazol-4-yl)-1,3-oxazinan-2-oneC14H14BrN3O2[α]D25 = +5.6 (c 1, CHCl3)Source of chirality: Ellman’s auxiliaryAbsolute configuration: (4S,6R)
(4S,6S)-6-(Bromomethyl)-4-methyl-4-(1-methyl-1H-pyrazol-4-yl)-1,3-oxazinan-2-oneC10H14BrN3O2[α]D25 = +17.5 (c 1, CHCl3)Source of chirality: Ellman’s auxiliaryAbsolute configuration: (4S,6S)
(S)-6-(1-Ethyl-1H-pyrazol-4-yl)-piperidine-2,4-dioneC10H13N3O2[α]D25 = −28.0 (c 0.5, CHCl3)Source of chirality: Ellman’s auxiliaryAbsolute configuration: (S)
(S)-6-(1-Methyl-1H-pyrazol-4-yl)-piperidine-2,4-dioneC9H11N3O2[α]D25 = −54.4 (c 0.5, CHCl3)Source of chirality: Ellman’s auxiliaryAbsolute configuration: (S)
(S)-6-(1-Ethyl-3-methyl-1H-pyrazol-4-yl)-piperidine-2,4-dioneC11H15N3O2[α]D25 = −70.4 (c 0.5, CHCl3)Source of chirality: Ellman’s auxiliaryAbsolute configuration: (S)
(S)-6-(1-Phenyl-1H-pyrazol-4-yl)-piperidine-2,4-dioneC14H13N3O2[α]D25 = −27.4 (c 0.5, CHCl3)Source of chirality: Ellman’s auxiliaryAbsolute configuration: (S)
(S)-6-Methyl-6-(1-methyl-1H-pyrazol-4-yl)-piperidine-2,4-dioneC10H13N3O2[α]D25 = +49.0 (c 0.5, CHCl3)Source of chirality: Ellman’s auxiliaryAbsolute configuration: (S)
