Chemistry Reference
In-Depth Information
Fig. 5.13
Synthetic route of:
a
KAPs(Ph-PPh
3
)-Pd,
b
PS-PPh
2
-Pd and,
c
KAPs(Ph)-PPh
3
-Pd.
Big balls
represent PPh
3
or PPh
2
functional groups.
Small balls
represent PdCl
2
.
Solid line
repre-
sents boundary of material particles.
Dashed lines
represent inner network of material particles.
Reprinted with permission from Ref. [
10
]. Copyright 2012, Wiley-VCH
5.3.1 Jorgensen-Hayashi Catalyst
Wang et al. reported one of the most versatile organocatalysts [
11
]. Via a bottom-
up strategy, the Jorgensen-Hayashi catalyst has been successfully designed and
embedded into a nanoporous polymer JH-CPP (Fig.
5.14
). JH-CPP has high BET
surface area with a value of 881 m
2
g
−
1
, wide openings, and interconnected pores.
Increasing the accessibility of catalytic sites and facilitating the mass transport
process ensured JH-PP possesses excellent catalytic activity. JH-CPP catalyst was
utilized for catalyzing asymmetric Michael addition of aldehydes to nitroalkenes.
It gave desired products in good to high yield (67-99 %), high enantioselectiv-
ity (93-99 % ee), and high diastereoselectivity (d.r. of 74:26-97:3) (Table
5.3
).
In addition, the JH-CPP catalyst showed high stability, indicated by the recycling
experiment. JH-CPP could be reused at least for four times without the loss of
enantioselectivity (97-99 % ee) and diastereoselectivity (d.r. 92:8-88:12).
