Asymmetric hydrogenation of unsaturated ureas with the BIPI ligands

作者：Busacca Carl A^*; Lorenz Jon C; Grinberg Nelu; Haddad Nizar; Lee Heewon; Liang Zhibin Li Mary; Reeves Diana; Saha Anjan; Varsolona Rich; Senanayake Chris H

来源：Organic Letters, 2008, 10(2): 341-344.

DOI：10.1021/ol7028542

Asymmetric hydrogenation of unsaturated urea esters with the 131131 Ligands has been examined. Optimization of the P-N ligand structure has led to the development of chiral rhodium catalysts capable of producing the targets with > 99% ee. The critical phosphine borane SNAr reaction needed for ligand synthesis has been optimized to give the adducts in high yield at ambient temperature with no racemization. An extremely concise, economical, and scalable sequence to these important new ligands for catalysis of asymmetric hydrogenation has been developed.

• 出版日期2008-1-17