64
X. Feng et al.
Table 2.25 Hydrosilylation of imines
N
Ar
R'
R
HN
Ar
R'
R
26a (4 mol %)
PhMe 2 SiH (1.1 equiv)
3
5
then CH 3 OH workup
entry product
yield (%) ee (%)
1
5h’
Ph
Me
HN
91
80
2
5o’
Ph
Me
HN
Me
Me
47
80
3
5g’
Ph
Me
HN
71
80
4
5p’
Me
HN
75
86
5
5i
Ph
Me
HN
Ph
~100
64
6
5q’
Ph
Me
HN
Bu
79
58
7
5i’
Ph
Et
HN
62
28
68 was obtained through a Pd-catalyzed directed ortho-C−H iodination and methylation. Various aryl substituents can be easily introduced through Suzuki coupling
reactions. Followed by DIBAL-H reduction, PCC oxidation, and Wittig-reaction,
chiral dienes 64a − e were afforded in 81–85% yields (Scheme 2.18). The Du group
applied these chiral boranes derived from chiral spiro dienes in the asymmetric Pierstype hydrosilylation of simple ketones, giving the desired secondary alcohols in high
yields with up to 90% ee (Table 2.29).
X. Feng et al.
Table 2.25 Hydrosilylation of imines
N
Ar
R'
R
HN
Ar
R'
R
26a (4 mol %)
PhMe 2 SiH (1.1 equiv)
3
5
then CH 3 OH workup
entry product
yield (%) ee (%)
1
5h’
Ph
Me
HN
91
80
2
5o’
Ph
Me
HN
Me
Me
47
80
3
5g’
Ph
Me
HN
71
80
4
5p’
Me
HN
75
86
5
5i
Ph
Me
HN
Ph
~100
64
6
5q’
Ph
Me
HN
Bu
79
58
7
5i’
Ph
Et
HN
62
28
68 was obtained through a Pd-catalyzed directed ortho-C−H iodination and methylation. Various aryl substituents can be easily introduced through Suzuki coupling
reactions. Followed by DIBAL-H reduction, PCC oxidation, and Wittig-reaction,
chiral dienes 64a − e were afforded in 81–85% yields (Scheme 2.18). The Du group
applied these chiral boranes derived from chiral spiro dienes in the asymmetric Pierstype hydrosilylation of simple ketones, giving the desired secondary alcohols in high
yields with up to 90% ee (Table 2.29).