Enantioselective Denitrogenative Annulation of 1H-Tetrazoles with Styrenes Catalyzed by Rhodium.

Sulfonylation of 1H-tetrazoles with triflic anhydride in the presence of chiral rhodium(II) carboxylate dimers causes denitrogenation to generate α-azo rhodium(II) carbenoid species as new types of donor/acceptor carbenoids, which then readily react with styrenes to afford 3,5-diaryl-2-pyrazolines with a high degree of enantioselectivity.