In:
Chemistry – A European Journal, Wiley, Vol. 20, No. 35 ( 2014-08-25), p. 11019-11028
Abstract:
Construction of porous organic polymers (POPs) as asymmetric catalysts remains as an important but challenging task. Herein, we exploit the “bottom‐up” strategy to facilely synthesize an α,α,α′,α′‐tetraaryl‐1,3‐dioxolane‐4,5‐dimethanol (TADDOL)‐based chiral porous polymer ( TADDOL ‐ CPP ) for highly efficient asymmetric catalysis. Constructed through the covalent linkages among the three‐dimensional rigid monomers, TADDOL ‐ CPP possesses hierarchical porous structure, high Brunauer–Emmett–Teller (BET) surface area, together with abundant and uniformly‐distributed chiral sites. In the presence of [Ti(O i Pr) 4 ], TADDOL ‐ CPP acts as a highly efficient and recyclable catalyst in the asymmetric addition of diethylzinc (Et 2 Zn) to aromatic aldehydes. Based on the direct observation of the key intermediates, the reaction mechanism has been revealed by solid‐state 13 C magic‐angle spinning (MAS) NMR spectroscopy. In combination with the catalytic testing results, characterization on the working catalyst provides further information for understanding the structure–activity relationship. We suggest that the catalytic activity of TADDOL ‐ CPP is largely affected by the structural rigidity, cooperative catalysis, local chiral environment, and hierarchical porous framework. We expect that the information obtained herein will benefit to the designed synthesis of robust POP catalysts toward practical applications.
Type of Medium:
Online Resource
ISSN:
0947-6539
,
1521-3765
DOI:
10.1002/chem.201403002
Language:
English
Publisher:
Wiley
Publication Date:
2014
detail.hit.zdb_id:
1478547-X
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