Soderquist Borabicyclodecanes

By: William Sommer, Aldrich ChemFiles 2008, 8.6, 8.

Aldrich ChemFiles 2008, 8.6, 8.

In the past 20 years, the asymmetric allylboration of aldehydes has become an essential reaction for the synthesis of homoallylic or homopropargylic alcohols. Soderquist et al. developed a robust, versatile and recyclable pseudoephedrine reagent improving the reaction performance and selectivity. Treatment of these air stable crystalline pseudoephedrine borinic acid complexes with the appropriate Grignard reagent gives access to homoallylic or homopropargylic alcohols and -allenyl carbinols via symmetric allyl-, propargyl-, and allenylboration reactions. Allyboration reactions occur rapidly, can be performed in the presence of Mg salts, and the degree of asymmetric induction is only minimally affected by temperature. Moreover, the reagents are easily recycled in good yield. The reagents also perform well in asymmetric crotylborations,1allylborations of imines,2 and the alkynylboration of N-acylimines to give chiral N-propargylamides (Scheme 1).3


Scheme 1.

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Materials

     

References

  1. Burgos, C. H. et al. J. Am. Chem. Soc. 2005, 127, 8044.
  2. Hernandez, E. et al. Pure Appl. Chem. 2006, 78, 1389.
  3. Gonzales, A. Z. et al. Org. Lett. 2006, 8, 3331.

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