We are interested in both development of novel chemical transformations, especially those of transition-metal catalysis, and directed SN2 glycosylation chemistry.
Au-Catalyzed Tandem Reactions (For Recent Results, See (A Summary Of Au Chemistry))
- Au salts have been shown as exceptional catalysts to activate alkynes for nucleophilic reactions. However, Au-catalyzed activation of allenes has not been studied much. We are interested in general in Au-catalyzed reactions of allenes. Currently we are studying the reactivities of allenyl esters in the presence of Gold catalysts. Those allenyl esters can be generated in situ from readily available propargylic esters via the catalysis of the very same Au salts. A range of efficient Au-catalyzed tandem reactions of propargylic esters leading to novel structures and synthetically important intermediates have been developed. Examples are shown below.
Bifunctional Chiral Ligand Development
- Asymmetric Au(I)-catalyzed reactions face unique structural challenges: after the substrate coordinates with the gold catalyst, the ligand’s coordinating atom-gold-substrate alignment forms a nearly linear arrangement with an angle of approximately 180°, which keeps the ligand far from the reactive substrate. we have developed various bifunctional biaryl-2-ylphosphine ligands possessing a remote Lewis/Brønsted basic group for the implementation of metal–ligand cooperation in gold catalysis.
Directed SN2 Glycosylation
- Chemical synthesis of these complex carbohydrate structures hinges on the stereoselective construction of glycosidic bonds. we developed a new and general approach to SN2 glycosylation by employing a directing group that realizes both conversions from α donors to β products and from β donors to α products, accommodates a broad range of sugar types, requires only two linear steps for the installation of a designed leaving group, and achieves exceptional stereoselectivity with challenging secondary acceptors.