Highly diastereoselective preparation of chiral NHC-boranes stereogenic at the boron atom.
Fiche publication
Date publication
juillet 2019
Journal
Chemical science
Auteurs
Membres identifiés du Cancéropôle Est :
Dr FIGLIOLA Carlotta
Tous les auteurs :
Aupic C, Abdou Mohamed A, Figliola C, Nava P, Tuccio B, Chouraqui G, Parrain JL, Chuzel O
Lien Pubmed
Résumé
Stereogenic main group elements are clearly generating interest in the enantioselective catalysis field. Surprisingly, while chiral organoboron reagents are very useful in stereoselective transformations, few scaffolds stereogenic at boron and configurationally stable have been reported to date. Herein, we describe an original library of chiral NHC-boranes, stereogenic at the boron atom, that has been prepared in only a few steps and in good yields (up to 93%). Key steps involve a chlorination/arylation sequence in the presence of simple Grignard reagents from bicyclic NHC-boranes. The high and unprecedented diastereoselectivity observed during the second step (up to 99 : 1 dr) has been rationalized through a plausible S1 mechanism thanks to EPR observations and DFT calculations.
Référence
Chem Sci. 2019 07 14;10(26):6524-6530