| Article ID | Journal | Published Year | Pages | File Type |
|---|---|---|---|---|
| 1345578 | Tetrahedron: Asymmetry | 2013 | 5 Pages |
Herein we describe for the first time the enantioselective catalytic arylation of ethyl glyoxalate using phenylboron reagents and chiral rhodium(I)–NHC catalysts. KOtBu was the base of choice, along with tert-amyl alcohol as the solvent. A novel chiral bis-imidazolium salt was synthesized and evaluated for the first time in this catalytic transformation. Although moderate enantioselectivities (up to 34% ee) were obtained for the phenylation reaction, despite the excellent yields, very low enantioselectivities were obtained using other arylboronic acids with a variety of chiral rhodium(I)–NHC catalysts.
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3,3′-(((2R,3R,5R,6R)-5,6-Dimethoxy-5,6-dimethyl-1,4-dioxane-2,3-diyl)bis(methylene))bis(1-benzyl-1H-imidazol-3-ium) chlorideC30H38Cl2N4O4[α]D23=-94.8 (c 0.62, CHCl3)Source of chirality: chiral poolAbsolute configuration: (2R,3R,5R,6R)
