Ruthenium(II)-Catalyzed Tandem C-H Allylation and [3 + 2] Dipolar Cycloaddition to Construct Bridged Tetracycles

Org Lett. 2022 Nov 11;24(44):8115-8119. doi: 10.1021/acs.orglett.2c03085. Epub 2022 Oct 31.

Abstract

The ruthenium(II)-catalyzed tandem C-H allylation and intramolecular dipolar cycloaddition between azomethine imines and 2-methylidenetrimethylene carbonate is described herein. The initially formed β-substituted allyl fragment could trigger the exotype [3 + 2] cycloaddition with the polar azomethine group, resulting in the formation of bridged tetracycles bearing a hydroxymethylene group at a bridgehead carbon center. A wide substrate scope and broad functional group compatibility were observed. The gram-scale synthesis and synthetic transformations demonstrate the synthetic utility of this process.