Bonet A, Odachowski M, Leonori D, Essafi S, Aggarwal VK * University of Bristol, UK
Enantiospecific
sp2–sp3
Coupling of Secondary and Tertiary Boronic Esters.
Nature Chem. 2014;
6: 584-589
Key words
boron - aryllithium - cross-coupling
Significance
Aggarwal and co-workers report an effective, general method for coupling electron-rich (hetero)aromatics with enantioenriched secondary and tertiary boronic esters. The reaction involves the initial formation of a boronate complex followed by activation of the electron-rich aromatic by NBS, which triggers a stereospecific 1,2-migration and subsequent elimination–rearomatization.
Comment
The methodology uses simple, readily available reagents and proceeds without transition metals. Broad scope with respect to the boronic ester and the electron-rich aromatic was illustrated, and the reactions proceeded with complete stereospecificity.
