Journal
CELLULOSE
Volume 29, Issue 11, Pages 6283-6299Publisher
SPRINGER
DOI: 10.1007/s10570-022-04654-y
Keywords
Immobilization; Asymmetric cyclopropanation; Dirhodium; NMR spectroscopy; Dynamic nuclear polarization
Funding
- Deutsche Forschungsgemeinschaft [Bu-911/27-1, HE 3243/4-1]
Ask authors/readers for more resources
A novel and efficient approach was developed for the functionalization of microcrystalline cellulose (MCC) in order to immobilize chiral dirhodium catalysts for asymmetric cyclopropanation reactions. The modified cellulose material showed excellent stability and good separation characteristics. The produced catalyst demonstrated high enantioselectivity and recyclability in the cyclopropanation reaction.
A novel, efficient approach for the functionalization of microcrystalline cellulose (MCC) is presented. The as-obtained material allows the immobilization of chiral dirhodium catalysts preserving their enantioselectivity in asymmetric cyclopropanation reactions. As model, microcrystalline cellulose is modified with a polyethylene glycol derived linker, and Rh-2(S-DOSP)(4) is grafted on the material to produce a heterogeneous catalyst. SEM images at different stages of the immobilization show an unchanging uniform morphology, providing constantly good separation characteristics. The modification of the cellulose material with the polyethylene derived linker and the immobilization process are monitored using DNP enhanced H-1 -> C-13 CP MAS NMR, quantitative F-19 MAS NMR, TGA and ICP-OES analysis, confirming the success of the immobilization as well as the stability of bonds between the used linker molecule and the cellulose material. Finally, the evaluation of the produced catalyst is demonstrated in the asymmetric cyclopropanation reaction between styrene and methyl(E)-2-diazo-4-phenylbut-3-enoate showing excellent enantioselectivity with an ee of nearly 90% over a wide temperature range as well as good recyclability characteristics in four consecutive catalysis cycles.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available