“…Schwartz reported a stereoselective pinacol coupling with a cyclopentadienetitanium complex . Pinacol-type couplings were also developed by using a Zn−Cu couple, Mg, Mn, Zn, In, Sm, Al/NaOH (or KOH), Al/F - , Ga, Cd, and other metals in aqueous media (eq 124). Under sonication, Kim and co-workers 482 found that aromatic aldehydes homocoupled to generate pinacol-type products.…”