Chiral Aniline Synthesis via Stereospecific C(sp3)-C(sp2) Coupling of Boronic Esters with Aryl Hydrazines.

An enantiospecific coupling between alkylboronic esters and lithiated aryl hydrazines is described. The reaction proceeds under transition-metal-free conditions and is promoted by acylation of a hydrazinyl arylboronate complex, which triggers a N-N bond cleavage with concomitant 1,2-metalate rearrangement. Judicious choice of the acylating agent enabled the synthesis of ortho- and para-substituted anilines with essentially complete enantiospecificity from a wide range of boronic ester substrates.