Asymmetric reductive amination of beta-keto amides catalyzed by the chiral catalyst Ru(OAc)(2)((R)-dm-segphos) produces unprotected beta-amino amides with high yields and high enantioselectivities (94.7-99.5% ee). This "one-pot" methodology is general in substrate scope and has been successfully employed to produce sitagliptin with 99.5% ee and 91% assay yield. The excellent reaction efficiency is attributed to the remarkable tolerance to high concentrations of ammonium ion, the high chemoselectivity, and the high enantiosetectivity (99.5% ee) of the Ru catalyst system.
Highly Efficient Synthesis of β-Amino Acid Derivatives via Asymmetric Hydrogenation of Unprotected Enamines
作者:Yi Hsiao、Nelo R. Rivera、Thorsten Rosner、Shane W. Krska、Eugenia Njolito、Fang Wang、Yongkui Sun、Joseph D. Armstrong、Edward J. J. Grabowski、Richard D. Tillyer、Felix Spindler、Christophe Malan
DOI:10.1021/ja047901i
日期:2004.8.1
A direct asymmetrichydrogenation of unprotected enamino esters and amides is described. Catalyzed by Rh complexes with Josiphos-type chiral ligands, this method gives beta-amino esters and amides in high yield and high ee (93-97% ee). No acyl protection/deprotection is required.
描述了未保护的烯氨基酯和酰胺的直接不对称氢化。该方法由具有 Josiphos 型手性配体的 Rh 络合物催化,以高产率和高 ee (93-97% ee) 得到 β-氨基酯和酰胺。不需要酰基保护/脱保护。