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
Full chirality transfer in the synthesis of hindered tertiary boronic esters under in situ lithiation–borylation conditions
作者:D. J. Blair、S. Zhong、M. J. Hesse、N. Zabaleta、E. L. Myers、V. K. Aggarwal
DOI:10.1039/c6cc00536e
日期:——
Using non-cryogenic lithiation-borylation, sterically hindered tertiary neopentyl glycol boronicesters can be prepared from secondary benzylic carbamates with full chirality transfer.
使用非低温锂化-硼酸化,可以从具有完全手性转移的仲苄基氨基甲酸酯制备位阻叔新戊二醇硼酸酯。
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
Stereospecific conversion of alcohols into pinacol boronic esters using lithiation–borylation methodology with pinacolborane
作者:Stefan Roesner、Christopher A. Brown、Maziar Mohiti、Alexander P. Pulis、Ramesh Rasappan、Daniel J. Blair、Stéphanie Essafi、Daniele Leonori、Varinder K. Aggarwal
DOI:10.1039/c4cc00993b
日期:——
The synthesis of primary and secondary pinacol boronic esters via lithiation–borylation of carbamates and benzoates with pinacolborane is described.
通过对氨基甲酸酯和苯甲酸酯进行锂化-硼化反应,使用二甲基二醇硼烷合成初级和次级的丙二醇硼酸酯。
Regio- and Enantiospecific Rhodium-Catalyzed Allylic Substitution with an Acyl Anion Equivalent
作者:P. Andrew Evans、Samuel Oliver
DOI:10.1021/ol402336u
日期:2013.11.15
The construction of enantiomerically enriched acyclic quaternary substituted ketones via the regio- and enantiospecific rhodium-catalyzed allylic alkylation reaction of chiral nonracemic tertiary alcohols with cyanohydrin pronucleophiles is described. This approach provides an alternative method to the α-arylation and vinylation of acyclic disubstituted ketone enolates, which remains a challenging