Yue-Jin Liu

Copper/Silver‐Mediated Direct ortho‐Ethynylation of Unactivated (Hetero)aryl CH Bonds with Terminal Alkyne

A copper/silver-mediated oxidative ortho-ethynylation of unactivated aryl C-H bonds with terminal alkyne has been developed. The reaction uses the removable PIP directing group and features broad substrate scope, high functional-group tolerance, and compatibility with a wide range of heterocycles, providing an efficient synthesis of aryl alkynes. This procedure highlights the potential of copper catalysts to promote unique, synthetically enabling C-H functionalization reactions that lie outside of the current scope of precious metal catalysis.

Copper-/Silver-Mediated Arylation of C(sp2)–H Bonds with 2-Thiophenecarboxylic Acids

A copper/silver-mediated arylation of (hetero)aryl C-H bonds with 2-thiophenecarboxylic acids has been achieved. The protocol features a broad substrate scope and high functional group tolerance. Preliminary mechanistic studies indicate that a cascade protodecarboxylation/dehydrogenative coupling process is likely involved.

Divergent and Stereoselective Synthesis of β‐Silyl‐α‐Amino Acids through Palladium‐Catalyzed Intermolecular Silylation of Unactivated Primary and Secondary C−H Bonds

A general and practical PdII -catalyzed intermolecular silylation of primary and secondary C-H bonds of α-amino acids and simple aliphatic acids is reported. This method provides divergent and stereoselective access to a variety of optical pure β-silyl-α-amino acids, which are useful for genetic technologies and proteomics. It can also be readily performed on a gram scale and the auxiliary can be easily removed with retention of configuration. The synthetic importance of this method is further demonstrated by the late-stage functionalization of biological small molecules, such as (-)-santonin and β-cholic acid. Moreover, several key palladacycles were successfully isolated and characterized to elucidate the mechanism of this β-C(sp3 )-H silylation process.