Improved method for the conversion of pinacolboronic esters into trifluoroborate salts: facile synthesis of chiral secondary and tertiary trifluoroborates
作者:Viktor Bagutski、Abel Ros、Varinder K. Aggarwal
DOI:10.1016/j.tet.2009.10.002
日期:2009.11
A general method for the preparation of virtually any potassium trifluoroborate salt from the corresponding pinacolboronic ester is reported. Thus, conditions for an azeotropic removal of pinacol from the reaction mixture were found to afford the desired potassium trifluoroborates of sufficient purity (>95%) in nearly quantitative yields irrespective of the nature of the product. The utility of this
Protodeboronation of Tertiary Boronic Esters: Asymmetric Synthesis of Tertiary Alkyl Stereogenic Centers
作者:Stefan Nave、Ravindra P. Sonawane、Tim G. Elford、Varinder K. Aggarwal
DOI:10.1021/ja1084207
日期:2010.12.8
tertiary boranes undergo efficient protodeboronation with carboxylic acids, tertiary boronicesters do not. Instead, we have discovered that CsF with 1.1 equiv of H2O (on tertiary diarylalkyl boronicesters) or TBAF·3H2O (on tertiary aryldialkyl boronicesters) effect highly efficient protodeboronation of tertiary boronicesters with essentially complete retention of configuration. Furthermore, substituting