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Sulfoximines as Ligands in Asymmetric Metal Catalysis

In this type of hetero-Diels-Alder reaction ethylene-bridged bissulfoximines 55 were also applied as ligands, giving bicyclic products with up to 99% ee [59, 60]. It is noteworthy that these results compared very well with those obtained using the well-established Cu(II)/BOX-based systems, which were investigated by j0r-gensen and afforded cycloaddition products with up to 97% ee [61]. [Pg.163]

An interpretation of the results and a hypothesis on potential intermediates was difficult at this stage, since no defined complexes could be obtained. The first identification of species present in solution during the catalysis of the Diels-Alder reaction was achieved in a collaboration between our group and three physical chemists, Bertagnolli, Gescheidt, and Schweiger [64]. Using various techniques [Pg.163]

During the data optimization a schematic representation of a species was transmitted, which is shown here as structure 79. It differed from the final result, but proved most stimulating for our future ligand design. [Pg.164]

From this initially proposed (incorrect) arrangement 79 it was apparent that the bissulfoximine ligand had two unequal binding sites. The two sulfoximine nitrogens differed in their position This meant that the ligand had lost its C2-symmetry and that it would also be worthwhile to study Q-symmetric sulf-oximines that could - perhaps - lead to high enantioselectivities as well. [Pg.164]

The results of the hetero-Diels-Alder reaction between 70 and 71 then confirmed our hypothesis. Even with these Q-symmetric easy-to-come-by sulfoximines, cycloaddition product 72 was formed with up to 96% ee [65]. [Pg.165]


See other pages where Sulfoximines as Ligands in Asymmetric Metal Catalysis is mentioned: [Pg.151]    [Pg.153]    [Pg.155]    [Pg.157]    [Pg.159]    [Pg.161]    [Pg.162]    [Pg.163]    [Pg.165]    [Pg.169]    [Pg.151]    [Pg.153]    [Pg.155]    [Pg.157]    [Pg.159]    [Pg.161]    [Pg.162]    [Pg.163]    [Pg.165]    [Pg.169]    [Pg.150]    [Pg.170]    [Pg.162]    [Pg.1067]    [Pg.1067]    [Pg.132]    [Pg.92]   


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A asymmetric

Asymmetric catalysis

Asymmetrical ligands

Metal, as ligands

Metallation, asymmetric

Metals in catalysis

Sulfoximine

Sulfoximines

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