Synthesis 2019; 51(10): 2221-2229
DOI: 10.1055/s-0037-1610697
paper
© Georg Thieme Verlag Stuttgart · New York

Further Structural Modification of Sulfur-Stabilized Silicon Cations with Binaphthyl Backbones

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Institut für Chemie, Technische Universität Berlin, Strasse des 17. Juni 115, 10623 Berlin, Germany   eMail: martin.oestreich@tu-berlin.de
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This research was supported by the Deutsche Forschungsgemeinschaft (Grant No. Oe 249/12-1).
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Publikationsverlauf

Received: 24. Januar 2019

Accepted: 29. Januar 2019

Publikationsdatum:
11. März 2019 (online)


Abstract

The synthesis and spectroscopic characterization of two novel cationic silicon–sulfur Lewis pairs with a chiral 4,4′-disubstituted binaphthyl silepine backbone are described. Both Lewis acids induce significant enantioselectivity in the model Diels–Alder reaction of cyclohexa-1,3-diene and chalcone but additional substitution of the binaphthyl backbone exerts a minimal effect on enantioinduction compared to previously reported Lewis acids. Another silicon cation with a chiral spirocyclic backbone induces enantioselectivity in the same range but its synthesis is laborious.

Supporting Information