56
X. Feng et al.
Table 2.19 Asymmetric hydrogenation of enol ethers 50
R'
R
1. chiral diene 9h (5 mol %)
HB(C 6 F 5 ) 2 10 (10 mol %)
t Bu 3 P (10 mol %)
H 2 (40 bar)
R''
OTMS
2. TBAF
R'
R
R''
OH
50
51
entry product
yield (%) ee (%)
1
51a
Ph
Me
OH
98
98
2
51b
Me
OH
Et
97
97
3
51c
Me
OH
F
93
95
4
51d
Me
OH
MeO
97
>99
5
51e
Me
OH
OMe
97
>99
6
51f
Me
OH
O
97
88
7
51g
Me
OH
S
97
97
8
51h
Me
OH
98
99
9
51i
OH
98
99