Formal Transesterification Reaction of But-3-enyl Esters Enabled by a Synergistic Nickel/Zinc Relay

The transition metal-catalyzed coupling reaction has renewed the role of ester as an electrophilic partner. In this context, we describe a synergistic Ni/Zn-catalyzed formal transesterification reaction of but-3-enyl esters with tetrahydrofuran and alkyl iodides to give 4-alkoxylbutyl esters. The aromatic and aliphatic esters are both competent electrophiles and thus broaden the substrate scope of esters in coupling reactions, because the electrophiles in previously reported work were strictly limited to aromatic ones. Mechanistic studies reveal that the C(acyl)-O bond or even more inert C(alkyl)-O bond of esters could be cleaved under nickel catalysis. Two catalytic cycles are proposed, which represent a new reaction pathway versus the traditional transesterification.