DEDICATED CLUSTER
FULL PAPERS
M. Eckert et al.
vent under reduced pressure a yellow crude oil was ob-
tained. Purification by kugelrohr distillation gave yellow oil;
yield: 1.39 g(94%). 1H NMR (400 MHz, CDCl3, TMS): d=
8.61 (1H, m, NCH), 8.45 (1H, OCH), 7.69 (1H, m,
NCHCH), 7.42 (1H, m, NCCH), 7.22 (1H, m, NCCCH),
3.69–3.51 (2H, OCH2), 3.14 (1H, s, NH), 1.38 (3H, s, CH3),
1.32 (3H, s, CH3); 13C NMR (100.10 MHz, CDCl3, TMS):
d=157.1, 149.4, 136.7, 123.7, 122.4, 91.9, 76.8, 59.9, 26.0, 23.8
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TypicalProcedure for the Racemization of ( S)-1-
Phenylethanol
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To a Schlenk-type flask containing1–5 mol% of a rutheni-
um catalyst and 1–5 mol% of KO-tBu (if required) was
added in toluene (5 mL). The solution was stirred at 708C
under an argon atmosphere prior to the introduction of (S)-
1-phenylethanol (0.5 mmol, 62 mg) at 708C. The ees were
monitored over time by takingaliquots (0.5 mL) that were
filtered through a short silica gel pad column and diluted to
a suitable concentration in diethyl ether for chiral GC analy-
sis. In case of in situ generated complexes ligand and Ru
precursor 9 were stirred for 2 h at room temperature or
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708C (see Table 1). For calculation of TOF and eeinitial
=
100%, TOF [hÀ1]=50[1À
(ee/100)]/(ct) where ee, c and t are
the enantiomeric excess, the catalyst loadingin mol% and
the time in hour respectively. In some cases (S)-1-phenyl-
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6) and TOF [hÀ1]=25[1À
A
TypicalProcedure for Dynamic Kinetic Resoul tion of
1-Phenylethanol
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In a round-bottom flask equipped with a distillation column
were introduced potassium carbonate (207 mg, 1.5 mmol),
CAL B (20 mg) and toluene (10 mL). The suspension was
dried azeotropically at 708C under reduced pressure for 1 h.
A solution of Ru complex (75 mmol), KO-t-Bu (8.4 mg, 75
mmol), rac-1-phenylethanol (183 mg, 1.5 mmol) and n-dodec-
ane (63 mg, 0.370 mmol) in toluene (5 mL) was stirred at
708C for 1 h and cannulated to the CAL B suspension and
isopropyl acetate (3 mmol) or isopropenyl acetate
(12 mmol) was then introduced. The resultingsuspension
was stirred under reduced pressure (280 mbar) at 708C and
monitored in time by takingaliquots that were subjected to
chiral GC analysis.
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2608
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Adv. Synth. Catal. 2007, 349, 2603 – 2609