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Helvetica Chimica Acta – Vol. 92 (2009)
AD-H 0.46 cm ˘ ꢁ 25 cm from Daicel. Chiral GC: Agilent Technologies 6890N Network GC system,
chiral GC column: Hydrodex-b-TBDAc. GC/MS: GC Varian 3400, achiral GC column: Macherey-Nagel
optima 5 MS 30 m ꢁ 0.25 mm, 0.25 mm film). 1H- and 13C-NMR spectra: Varian 300 and Bruker 500
spectrometer. MS: Thermo TSQ 700.
General Procedure for Olefin Epoxidation. [MnIII(salen)X] (0.058 mmol, 0.06 equiv.) and the donor
ligand are dissolved at r.t. in 10 ml of freshly distilled solvent under Ar. In the case of oxidation with m-
CPBA, 2.40 mmol (2.5 equiv.) of donor ligand were added; in the case of PhIO oxidation, 0.115 mmol
(0.12 equiv.) of donor ligand were used. With stirring, the substrate olefin (0.96 mmol, 1 equiv.) was
added to the soln., and 2 equiv. (1.92 mmol) of either PhIO or m-CPBAwas added slowly (ca. 5 min). The
reaction mixture was then stirred at r.t. for 5 h (m-CPBA) or 24 h (PhIO). Workup: If the oxidant was m-
CPBA, the reaction mixture was washed two times with 5% Na2CO3, and the org. phase was dried
(Na2SO4). The org. phase was filtered through a short SiO2 column and eluted with AcOEt/cyclohexane.
If the oxidant was PhIO, the crude mixture could be filtered directly through a SiO2 column and eluted
with AcOEt/cyclohexane. The absolute configurations of the major epoxide products (except for styrene
oxide) were not determined but assigned according to the literature.
Preparation of N-Oxide Ligands. The N-oxides used as promoters were prepared by m-CPBA
oxidation from their respective pyridine or quinoline precursors according to [9] and [10]. The
spectroscopic data of the N-oxides thus obtained are in agreement with those given in the literature.
REFERENCES
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Ojima, VCH Publishers Inc., New York, 1993, chap. 4.1.
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Received October 16, 2008