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Carbenes reaction with polystyrene

Cyclopropanation Reactions. Davies and Nagashima reported the first example of a catalytic asymmetric cyclopropanation of alkenes on a solid support. Carbene dimerization represents a limitation in solution phase, lowering yields and necessitating additional purification steps. Immobilization of the olefin 97 on a polystyrene diethylsilyl resin followed by reaction with various diazoacetates in the presence of a rhodium catalyst generated the cyclopropanes 98 and 99 in high yield and enabled the removal of dimerization products 102 through a simple wash step (Scheme 6.23). The products 100 and 101 were cleaved as a mixture of diastereomers from the resin under mild conditions. The stereoselectivity of the reaction was not influenced by the solid support, but rather by the catalyst selection most important, >90% ee was observed under these conditions. [Pg.184]


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See also in sourсe #XX -- [ Pg.194 ]




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Carbene reactions

Carbenes reactions

Polystyrene reaction

Reaction with carbenes

With Carbenes

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