X. Tu et al. / Inorganic Chemistry Communications 13 (2010) 404–407
407
linkage lengths which connected ZPS-IPPA and salen Mn(III) would
Acknowledgment
decrease resistance of heterogeneous catalytic system, and restrain
the free rotation of the reaction intermediate. Furthermore, more
Mn content of catalyst 3c resulted from also the longest linkage
length that can offer more catalytic centers maybe another causa-
tion for the better catalytic effect.
The authors are grateful to Southwest University of China for
financial support.
Appendix A. Supplementary material
Table 1 also summarizes the catalytic performance of the cata-
lyst 3c at different reaction temperatures. A decrease of reaction
temperature led to the decrease of the epoxide conversion. How-
ever, an increase of enantioselectivity was observed, which was
similar to the results reported previously in Ref. [23]. The reason
should be due to both an increase in enantiofacial selectivity in
the initial CÀO bond forming step and suppression of the trans-
pathway in the second step at low temperature [24].
Interestingly, this new type of heterogeneous catalysts showed
better catalytic activity and enantioselectivity for bulkier olefins
such as indene (Table 2).
The reusability of the title catalyst could be one of the most
important benefits of these heterogeneous chiral catalysts, for cor-
responding homogenous chiral catalysts are often expensive to
purchase or prepare. Thus, to assess the long-term stability and
Supplementary data associated with this article can be found, in
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