Cu-exchanged phosphotungestic acid: An efficient and reusable heteropoly acid for the cyclopropanation of alkenes via C-H insertion

Alkenes undergo smooth cyclopropanation with ethyl diazoacetate using a catalytic amount of Cu-exchanged phosphotungestic acid (Cu-TPA) in dichloromethane under mild reaction conditions to afford cyclopropanecarboxylates in high yields with moderate selectivity. The catalyst is recycled and reused for three to four subsequent runs with a minimal decrease of activity.

Graphical abstractAlkenes undergo smooth cyclopropanation with ethyl diazoacetate (EDA) using a catalytic amount of Cu-exchanged phosphotungestic acid (Cu-TPA) in dichloromethane under mild reaction conditions to afford cyclopropanecarboxylates in high yields with moderate selectivity. The catalyst is covered quantitatively and recycled for three to five subsequent runs with a minimal decrease of activity.Figure optionsDownload full-size imageDownload as PowerPoint slide