Versatility and broad applications of TangPhos and DuanPhos catalysts

摘要

The term "privileged ligands" was coined many years ago to describe systems that create effective asymmetric environments for mechanistically unrelated reactions (1). In terms of asymmetric hydrogenation electron rich P-chiral ligands (Figure 1) have been demonstrated to be privileged in this field. Rhodium catalysts based on these ligands have been shown to have high activity and selectivity for a broad range of asymmetric hydrogenation reactions. The first ligand in this class was DiPAMP introduced by Knowles in 1974 (2); Imamoto described the Bis-P* and mini-Phos systems in 1998 (3) and 1999 (4) respectively; and Hoge reported the TriChickenFootPhos (TCFP) ligand in 2004 (5). Chiral Quest, in collaboration with Xumu Zhang, has developed three ligands in this privileged class; TangPhos (6), Binapine (7) and DuanPhos (8). These highly effective catalysts are now being routinely applied to commercial manufacture of α-amino acids, β-amino acids, chiral amines, acids and amino alcohols by Chiral Quest in its new manufacturing plant in Suzhou, China (9).