Asymmetric Hydrosilylation

By: William Sommer, Aldrich ChemFiles 2008, 8.6, 4.

Aldrich ChemFiles 2008, 8.6, 4.

The asymmetric hydrosilylation of olefins has proven to be a useful method to access a variety of chiral alcohols.1 The introduction of the silica moiety allows further transformation of the molecule before converting it to the alcohol analogue. However, this particular reaction proved to be particularly challenging. To overcome this challenge Hayashi and co-workers synthesized a new chiral monodentate phosphine ligand using 1,1’-binaphtyl as a backbone.1This ligand, when used with palladium showed excellent stereoselectivities for the asymmetric hydrosilylation of 2,5-dihydrofurans.2 The versatility of this ligand was showcased in the hydrosilylation of a variety of meso bicyclic olefins containing 2,5-dihydrofuran skeleton, with enantioselectivities as high as 95% (Scheme 1). In a typical reaction, 0.1 mol% of palladium allyl chloride dimer, with 0.2 mol% of MOP ligand is used. A reaction time of 24 hours is required to achieve good yields.


Scheme 1.

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Materials

     

References

  1. Hayashi, T. Acc. Chem. Res. 2000, 33, 354.
  2. Uozomi, Y. et al. Tetrahedron Lett. 1993, 34, 2335.

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