Task-specific acidic ionic liquid-catalyzed efficient synthesis of β-enaminolactones from alkynoates and β-amino alcohols

By employing task-specific acidic ionic liquid as an efficient catalyst, a new method for the straightforward synthesis of β-enaminolactones has been demonstrated. A series of alkynoates in combination with various β-amino alcohols was efficiently converted into the desired products in good to excellent yields upon isolation. The skeleton of the seven-membered ring is generated via tandem intermolecular hydroamination and intramolecular transesterification processes. The developed synthetic protocol furnishes the desired products in a step- and atom-economic fashion with the advantages of high yields, broad substrate scope, good functional tolerance, and operational simplicity, offering an important basis for the construction of β-enaminolactones.