Scandium Cross-Linked Dendrimers as Lewis Acid Catalysts

Scandium Cross-Linked Dendrimers as Lewis Acid Catalysts 

Reetz and Giebel 62) anchored sulfonylated poly(propylene imine) dendrimers by a cross-linking reaction with Sc(OTf)3, resulting in a non-porous material 

In the Mukaiyama aldol additions of trimethyl-(l-phenyl-propenyloxy)-silane to give benzaldehyde and cinnamaldehyde catalyzed by 7 mol% supported scandium catalyst, a 1 1 mixture of diastereomers was obtained. Again, the dendritic catalyst could be recycled easily without any loss in performance. The scandium cross-linked dendritic material appeared to be an efficient catalyst for the Diels-Alder reaction between methyl vinyl ketone and cyclopentadiene. The Diels-Alder adduct was formed in dichloromethane at 0°C in 79% yield with an endo/exo ratio of 85 15. The material was also used as a Friedel-Crafts acylation catalyst (contain-ing7mol% scandium) for the formation of / -methoxyacetophenone (in a 73% yield) from anisole, acetic acid anhydride, and lithium perchlorate at 50°C in nitromethane. 

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E.4. Scandium Cross-Linked Dendrimers as Lewis Acid Catalysts... 

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See also in sourсe #XX -- [ , , ]

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