Page 112 - Catalysts for Fine Chemical Synthesis Vol 1 - Robert & Poignant

98 hydrolysis, oxidation and reduction

the difficulties in the determination of the enantiomeric excess; however, the
yields were similar to the results given in the literature for both methods.

6.3 ENANTIOSELECTIVE EPOXIDATION OF (E)-b-
METHYLSTYRENE BY D 2 -SYMMETRIC CHIRAL TRANS-
DIOXORUTHENIUM(VI) PORPHYRINS

Rui Zhang, Wing-Yiu Yu and Chi-Ming Che*
Department of Chemistry, The University of Hong Kong, Pokfulam Road, Hong Kong

6.3.1 PREPARATION OF THE TRANS-DIOXORUTHENIUM(VI)
)
COMPLEXES WITH D 2 SYMMETRIC PORPHYRINS (H 2 L 1ÿ3 [7]

R* R*
R* O R* O
O CO O O O O
O mcpba O
N N N N
N Ru N N Ru N
CH 2 Cl 2
O O O O
EtOH O O O
R* R*
O O
R* R*
Me Me Et Et
O O O O
O O
R*=
C C C C
C C
H 2 H 2 H 2 H 2
H 2 H 2
(L 1 ) (L 2 ) (L 3 )
Materials and equipment
. Dichloromethane (freshly distilled over P 2 O 5 under a nitrogen atmosphere),
5 mL
. m-Chloroperoxybenzoic acid (AR, Aldrich), 100 mg
II
. [Ru (L 1ÿ3 ) (CO) (EtOH)], 0.07 mmol
. Acetone (AR)±CH 2 Cl 2 (1:1), 20 mL
. Aluminum oxide (Brockman Grade II±III, basic), 20 g
. 10 mL Round-bottom flask with a magnetic stirrer bar
. Magnetic stirrer
. Vacuum pump

Procedure
II
1. A dichloromethane solution of [Ru (L 1ÿ3 ) (CO) (EtOH)] (0.07 mmol) was
added to a well-stirred dichloromethane solution of m-chloroperoxybenzoic
acid (100 mg, 0.62 mmol) in a 10 mL round-bottomed flask. After 3 to 5
minutes stirring, the mixture was poured onto a short dry alumina column.