Highly Selective Primary Alkoxycarboxylation and Esterification of Unprotected Pyranose Derivatives Mediated by Scandium(III) Triflate Catalysis

Synthetic Approaches to the New Drugs Approved during 2019

New drugs introduced to the market are privileged structures having affinities for biological targets implicated in human diseases and conditions. These new chemical entities (NCEs), particularly small molecules and antibody-drug conjugates, provide insight into molecular recognition and simultaneously function as leads for the design of future medicines. This review is part of a continuing series presenting the most likely process-scale synthetic approaches to 40 NCEs approved for the first time anywhere in the world in 2019.

Sc(OTf)3-mediated 1,3-dipolar cycloaddition-ring cleavage-rearrangement: a highly stereoselective access to Z-β-enaminonitriles

A novel and highly stereoselective synthesis of Z-β-enaminonitriles from azides and α,β-unsaturated nitriles is reported. The reaction proceeds via a 1,3-dipolar cycloaddition-ring cleavage-rearrangement cascade mediated by a catalytic amount of Sc(OTf)3. A plausible reaction mechanism for this process is depicted.

A Rapid and Practical Catalytic Esterification for the Preparation of Caffeic Acid Esters

A convenient and practical catalytic method for the preparation of caffeic acid esters is reported. This esterification was carried out with high efficiency in the presence of ytterbium triflate in nitromethane without any other auxiliary reagents. The wide scope of application and especially the higher reactivity and more convenient procedure than previous methods make it a valuable application for the synthesis of caffeic acid esters and other cinnamic acid esters.