58
X. Feng et al.
Table 2.20 Catalytic asymmetric hydrogenation of silyl enol ethers 48
R
1
R
3
R
2
OTMS
1. HB(C 6 F 5 ) 2 10
chiral diyne 52a
t Bu 3 P, H 2
2. TBAF
R
1
R
3
R
2
OH
50
51
entry product
yield (%) ee (%)
1
51a
Ph
Me
OH
90
95
2
51c
Me
OH
F
80
98
3
51g
Me
OH
S
95
96
4
51h
Me
OH
82
97
5
51i
OH
92
98
6
51j
Me
OH
Cl
90
99
7
51k
Me
OH
Br
92
98
8
51l
Me
OH
97
92
9
51m
Me
OH
S
99
93