An Improved Synthesis of Chiral 2,2′-Bipyridine Ligand C3-ACBP Without Column Chromatography

Abstract A method for purifying compounds bearing pyridine structure from Mitsunobu reaction mixtures using zinc chloride and releasing bipyridines from Ullmann coupling reaction mixtures by using sulfide anion for competitively coordinating the copper ion were developed for the facile synthesis of the chiral 2,2′-bipyridine ligand (Ra ,S,S)-C3-ACBP. With these improvements, an improved synthesis of the chiral ligand at a 7 gram scale has been fulfilled in 48% overall yield without column chromatography within 3–4 days.