Large-Scale Asymmetric Synthesis of a Cathepsin S Inhibitor
作者:Jon C. Lorenz、Carl A. Busacca、XuWu Feng、Nelu Grinberg、Nizar Haddad、Joe Johnson、Suresh Kapadia、Heewon Lee、Anjan Saha、Max Sarvestani、Earl M. Spinelli、Rich Varsolona、Xudong Wei、Xingzhong Zeng、Chris H. Senanayake
DOI:10.1021/jo9022809
日期:2010.2.19
cathepsin-S was prepared on large scale using a convergent synthetic route, free of chromatography and cryogenics. Late-stage peptide coupling of a chiral urea acid fragment with a functionalized aminonitrile was employed to prepare the target, using 2-hydroxypyridine as a robust, nonexplosive replacement for HOBT. The two key intermediates were prepared using a modified Strecker reaction for the aminonitrile
Asymmetric Hydrogenation of Unsaturated Ureas with the BIPI Ligands
作者:Carl A. Busacca、Jon C. Lorenz、Nelu Grinberg、Nizar Haddad、Heewon Lee、Zhibin Li、Mary Liang、Diana Reeves、Anjan Saha、Rich Varsolona、Chris H. Senanayake
DOI:10.1021/ol7028542
日期:2008.1.1
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 importantnew ligands for catalysis of asymmetric hydrogenation