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Modular Hydroxyamide and Thioamide Pyranoside‐Based Ligand Library from the Sugar Pool: New Class of Ligands for Asymmetric Transfer Hydrogenation of Ketones
Author(s) -
Coll Mercè,
Pàmies Oscar,
Diéguez Montserrat
Publication year - 2014
Publication title -
advanced synthesis and catalysis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.541
H-Index - 155
eISSN - 1615-4169
pISSN - 1615-4150
DOI - 10.1002/adsc.201301112
Subject(s) - thioamide , chemistry , amide , moiety , ligand (biochemistry) , transfer hydrogenation , aryl , absolute configuration , stereochemistry , substituent , enantiomer , combinatorial chemistry , organic chemistry , catalysis , biochemistry , alkyl , receptor , ruthenium
A large library of pyranoside‐based hydroxyamide and thioamide ligands has been synthesized for asymmetric transfer hydrogenation in an attempt to expand the scope of the substrates to cover a broader range of challenging heteroaromatic and aryl/fluoroalkyl ketones. These ligands have the advantage that they are prepared from commercial D ‐glucose, D ‐glucosamine and α‐amino acids, inexpensive natural chiral feedstocks. By carefully selecting the ligand components (substituents/configurations at the amide/thioamide moiety, the position of amide/thioamide group and the configuration at C‐2), we found that pyranoside‐based thioamide ligands provided excellent enantioselectivities (in the best cases, ee s of >99% were achieved) in a broad range of ketones, including the less studied heteroaromatics and challenging aryl/fluoroalkyls. Note that both enantiomers of the reduction products can be obtained with excellent enantioselectivities by simply changing the absolute configuration of the thioamide substituent.