| Article ID | Journal | Published Year | Pages | File Type |
|---|---|---|---|---|
| 1347731 | Tetrahedron: Asymmetry | 2008 | 8 Pages |
Treatment of (1R)-camphorquinone 2 with (trifluoromethyl)trimethylsilane in the presence of catalytic amounts of caesium fluoride in DME at room temperature yields two pairs of exo/endo isomers of trifluoromethylated silylated alcohols 5 and 6. In this case, nucleophilic addition of the CF3 anion occurs neither regio- nor stereoselectively. On the other hand, the analogous reaction with (1R)-camphorquinone 3-imines 3, followed by hydrolysis with 5 M HCl in ethanol, leads stereoselectively to (1R,2S)-2-hydroxy-2-(trifluoromethyl)bornan-3-one 8. The attempted reductions of the intermediate adducts with NaBH4 in ethanol gave the corresponding (1R,2S)-3-imino-2-(trifluoromethyl)bornan-2-ols 9 as the sole isomers in high yield. The configuration of C(2), that is, the endo course of the nucleophilic CF3 addition, was proven by X-ray crystallography. Furthermore, the reduction of the CN bond in 9 with DIBAL-H leads stereoselectively to the exo amino derivatives 10, which, by treatment with phosgene, smoothly form the fused 1,3-oxazolidin-2-ones 11. In contrast, the reduction of ketone 8 yields a mixture of the exo,exo- and exo,endo-2,3-diols 12.
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(1R,2S)-2-Hydroxy-2-(trifluoromethyl)bornan-3-oneC11H15F3O2De = 100%[α]D20=-119.2 (c 1.0, CHCl3)Source of chirality: enantiomerically pure substrateAbsolute configuration: (1R,2S)
(1R,2S)-3-Methylimino-2-(trifluoromethyl)bornane-2-olC12H18F3NODe = 100%[α]D20=-3.7 (c 0.9, CHCl3)Source of chirality: enantiomerically pure substrateAbsolute configuration: (1R,2S)
(1R,2S)-3-Ethylimino-2-(trifluoromethyl)bornane-2-olC13H20F3NODe = 100%[α]D20=+11.4 (c 1.1, CHCl3)Source of chirality: enantiomerically pure substrateAbsolute configuration: (1R,2S)
(1R,2S)-3-iso-Propylimino-2-(trifluoromethyl)bornane-2-olC14H22F3NODe = 100%[α]D20=+5.4 (c 1.0, CHCl3)Source of chirality: enantiomerically pure substrateAbsolute configuration: (1R,2S)
(1R,2S)-3-tert-Butylimino-2-(trifluoromethyl)bornane-2-olC15H24F3NODe = 100%[α]D20=+13.0 (c 1.3, CHCl3)Source of chirality: enantiomerically pure substrateAbsolute configuration: (1R,2S)
(1R,2S)-3-Cyclohexylimino-2-(trifluoromethyl)bornane-2-olC17H36F3NODe = 100%[α]D20=-5.45 (c 0.9, CHCl3)Source of chirality: enantiomerically pure substrateAbsolute configuration: (1R,2S)
(1R,2S)-3-[(1′R)-1′-Phenylethylimino]-2-(trifluoromethyl)-bornane-2-olC19H24F3NODe = 100%[α]D20=+72.6 (c 1.0, CHCl3)Source of chirality: enantiomerically pure substrateAbsolute configuration: (1R,2S,1′R)
(1R,2S)-3-Phenylimino-2-(trifluoromethyl)bornane-2-olC17H20F3NO2De = 100%[α]D20=+237.9 (c 0.8, CHCl3)Source of chirality: enantiomerically pure substrateAbsolute configuration: (1R,2S)
(1R,2S)-3-(4′-Methoxyphenylimino)-2-(trifluoromethyl)-bornane-2-olC18H22F3NO2De = 100%[α]D20=+395.4 (c 1.0, CHCl3)Source of chirality: enantiomerically pure substrateAbsolute configuration: (1R,2S)
(1R,2S,3R)-3-Methylamino-2-(trifluoromethyl)bornane-2-olC12H20F3NODe = 100%[α]D20=-5.5 (c 0.8, CHCl3)Source of chirality: enantiomerically pure substrateAbsolute configuration: (1R,2S,3R)
(1R,2S,3R)-3-Phenylamino-2-(trifluoromethyl)bornane-2-olC17H22F3NODe = 100%[α]D20=+12.0 (c 1.0, CHCl3)Source of chirality: enantiomerically pure substrateAbsolute configuration: (1R,2S,3S)
(1R,2S,6R)-1,5,10,10-Tetramethyl-2-(trifluoromethyl)-3-oxa-5-aza-tricyclo[5.2.1.0*2,6*]decan-4-oneC13H18F3NO2Ee = 100%[α]D20=-16.5 (c 1.0, CHCl3)Source of chirality: enantiomerically pure substrateAbsolute configuration: (1R,2S,6R)
(1R,2S,3R)-2-(Trifluoromethyl)bornane-2,3-diolC11H17F3O2De = max 91%[α]D20=-28.93 (c 1.1, CHCl3)Source of chirality: enantiomerically pure substrateAbsolute configuration: (1R,2S,3R)
(1R,2S,6R)-1,10,10-Trimethyl-2-(trifluoromethyl)-3,5-dioxa-tricyclo[5.2.1.0*2,6*]decan-4-oneC12H15F3O3De = 100%[α]D20=-8.6 (c 1.0, CHCl3)Source of chirality: enantiomerically pure substrateAbsolute configuration: (1R, 2S, 6R)
