Modular Furanoside Pseudodipeptides and Thioamides, Readily Available Ligand Libraries for Metal-Catalyzed Transfer Hydrogenation Reactions: Scope and Limitations

✍ Scribed by Mercedes Coll; Katrin Ahlford; Oscar Pàmies; Hans Adolfsson; Montserrat Diéguez

• Publisher: John Wiley and Sons
• Year: 2012
• Tongue: English
• Weight: 324 KB
• Volume: 354
• Category: Article
• ISSN: 1615-4150
• DOI: 10.1002/adsc.201100766

✦ Synopsis

Abstract

Two new highly modular carbohydrate‐based, pseudodipeptide and thioamide ligand libraries have been synthesized for the rhodium‐ and ruthenium‐catalyzed asymmetric transfer hydrogenation (ATH) of prochiral ketones. These series of ligands can be prepared efficiently from easily accessible D‐xylose and D‐glucose. The ligand libraries contain two main ligand structures (pseudodipeptide and thioamide) that have been designed by making systematic modifications to one of the most successful ligand families developed for the ATH. As well as studying the effect of these two ligand structures on the catalytic performance, we also evaluated the effect of modifying several of the ligand parameters. We found that the effectiveness of the ligands at transferring the chiral information in the product can be tuned by correctly choosing the ligand components (ligand structure and ligand parameters). Excellent enantioselectivities (__ee__s up to 99%) were therefore obtained in both enantiomers of the alcohol products using a wide range of substrates.