O.[C:2]1(C)[CH:7]=CC(S(O)(=O)=O)=C[CH:3]=1.C[C:14]([CH3:25])(/[C:20](/[CH2:23][CH3:24])=[CH:21]/[CH3:22])[C@@H:15]([OH:19])[CH2:16][CH2:17][OH:18].[C:26](=O)(O)[O-].[Na+]>CC(C)=O.S([O-])([O-])(=O)=O.[Cu+2].N1C=CC=CC=1>[CH3:3][C:2]1([CH3:7])[O:19][C@H:15](/[C:14](/[CH3:25])=[C:20](\[CH2:21][CH3:22])/[CH:23]([CH3:24])[CH3:26])[CH2:16][CH2:17][O:18]1
Anhydrous copper sulfate (478 mg, 3.0 mmol, 1.5 equiv), p-toluenesulfonic acid monohydrate (76 mg, 0.4 mmol, 0.2 equiv), and pyridine (24 μl, 0.3 mmol, 0.15 equiv) are added to a solution of (S)-(E)-4,4-dimethyl-5-ethyl-heptane-1,3-diol 28 (372 mg, 2.0 mmol) in acetone (30 ml). The mixture is stirred for 24 h at r.t. Saturated aqueous sodium bicarbonate solution (40 ml) is added, and the aqueous layer is extracted with diethyl ether (4×60 ml). The combined organic extracts are dred over magnesium sulfate and carefully concentrated in vacuo. Purification of the residue by flash column chromatography (pentane/diethyl ether 40:1) affords the title compound 29 (812 mg, 90%) as a colourless oil. 13C-NMR (50 MHz, CDCl3): δ=146.2; 119.3; 98.3; 74.2; 60.4; 42.9; 29.9; 26.2; 24.3; 21.2; 19.2; 14.4; 13.7
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