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BINOLs

Aldrich ChemFiles 2005, 5.4, 6.

Aldrich ChemFiles 2005, 5.4, 6.

The structural motif of 1,1’-binaphthyl is considered to be a privileged one for ligands in asymmetric synthesis. These kinds of ligands have shown broad applicability allowing high levels of enantiocontrol in many synthetic transformations.

2,2’-Bis(methoxymethoxy)-1-1’-binaphthalene

By modifying the 1,1’-binaphthyl backbone, the electronic and steric properties around the metal center of a chiral catalyst can be influenced, thus allowing the catalyst system to be tuned for specific applications.1 Starting from (R)-2,2’-bis(methoxymethoxy)-1-1’-binaphthalene, both 3- or 3,3’-di-substituted products can be obtained easily via ortho-metallation and subsequent treatment with an electrophile to give the corresponding BINOL derivatives in good to excellent yields and without detectable racemization (Scheme 14).2


Scheme 14


(R)-3,3’-Di-tert-butyl-5,5’,6,6’,7,7’,8,8’-octahydro-1-1’- (bi-2-naphthol) dipotassium salt

Octahydro-BINOL was demonstrated to be an effective ligand in Mo-catalyzed desymmetrization of a triene by asymmetric ring closing metathesis (Scheme 15).3


Scheme 15

Sigma-Aldrich now offers several new functionalized BINOLs for straightforward derivatization making modifications of your desired catalyst/ligand system more convenient.

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Materials

     

References

  1. For a review on modified BINOL ligands, see: Chen, Y. et al. Chem. Rev. 2003, 103, 3155.
  2. Cox, P. J. et al. Tetrahedron Lett. 1992, 33, 2253.
  3. (a) Dolman, S. J. et al. J. Am. Chem. Soc. 2002, 124, 6991; (b) Aeilts, S. L. et al. Angew. Chem., Int. Ed. 2001, 40, 1452.

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