Page 211 - Catalysts for Fine Chemical Synthesis Vol 1 - Robert & Poignant

asymmetric hydrogenation of carbon±carbon double bonds 199

Procedure

1. (R, R, p S, p S)-1,1 -bis [a-(Dimethylamino)propyl]-2,2 -bis(diphenylphosphi-
0
0
no)ferrocene (1.55 g) and 4-dimethylaminopyridine were placed in a 25 mL
degassed Schlenk flask equipped with a magnetic stirring bar; acetic anhyd-
ride (4.00 mL) was then added.
2. The reaction mixture was heated at 100 8C for 20 hours, after which time the
excess acetic anhydride was removed under high vacuum at 50 8C.
3. The resulting residue was chromatographed (eluent: n-hexane±ethyl acetate,
95:5) on silica gel pre-deactivated with triethylamine: n-hexane (2:98) to
afford the (R, R, p S, p S)-1,1 -bis(a-acetoxypropyl)-2,2 -bis(diphenylphosphi-
0
0
no)ferrocene as an orange solid (1.26 g, 78.0 %).

12.7.5 PREPARATION OF ( p S, p S)-1,1 -BIS(DIPHENYLPHOSPHINO)-
0
2,2 -BIS(1-ETHYLPROPYL)FERROCENE [(S,S)-3-PT-FERROPHOS]
0
OAc
CHEt 2
Et Et 3 Al
PPh 2
PPh 2
Fe Fe
PPh 2 CH 2 Cl 2
Et PPh 2
CHEt 2
OAc
Materials and equipment
. Dichloromethane, 16.6 mL
. Triethylaluminium (1.35 M in toluene), 6.14 mL
. Saturated sodium bicarbonate solution
. Saturated sodium potassium tartrate solution
. Diethyl ether, 30 mL
. 1 M Hydrochloric acid
. Brine
. Magnesium sulfate

. 100 mL Round-bottomed flask with a magnetic stirring bar
. Magnetic stirrer
. Separatory funnel, 125 mL
. Rotatory evaporator

Procedure
1. In a 100 mL round-bottomed flask equipped with a magnetic stirring bar
were placed dichloromethane (16.6 mL) and (R, R, p S, p S)-1,1 -bis (a-acet-
0
oxypropyl)-2,2 -bis(diphenylphosphino)ferrocene (1.25 g) under nitrogen.
0
Triethylaluminium in toluene (1.35 M, 6.14 mL) was added to the mixture