Regioselective Functionalization of 3‐Hydroxy‐pyridine Carboxylates by Neighboring Group Assistance

Abstract

Regioselective hydrolysis, transesterification, and aminolysis of unactivated, highly substituted pyridine esters were realized under mild conditions by employing neighboring group assisted catalysis. Excellent yields were achieved without active removal of the alcohol byproduct. Regioselective aminolysis had a considerable substrate scope ([hetero]aryl, alkyl and amino acid). A mechanism involving assistance by the deprotonated phenolic OH-group is suggested for hydrolysis and transesterification.

Neighboring Group Participation and Internal Catalysis Effects on Exchangeable Covalent Bonds: Application to the Thriving Field of Vitrimer Chemistry

“…Interestingly the transesterification reaction was reported to be regioselective on the ortho hydroxy ester, highlighting a reactivity increase (Scheme ). Nevertheless, in this case the regioselectivity is due to the hydrogen-bonding ability of the hydroxyl group, and the mechanism is associative, contrary to the previous example.…”