Telescoping Synthesis of γ-Lactone-Fused Indanones via C-H Activation and Rearrangement-Cyclization.

Telescoping synthesis represents a powerful strategy for the rapid assembly of complex molecular scaffolds, while obviating the need for isolation and purification of intermediates, making this strategy particularly appealing in modern synthetic efforts targeting pharmaceuticals and natural products. In this study, we present a rhodium-catalyzed ortho-C(sp2)-H olefination of tert-alkyl aryl ketones with methyl acrylate, followed by cascade double cyclizations that efficiently produce rare γ-lactone-fused indanones. The sequential rearrangement-cyclizations proceed through acid-promoted, carbonyl 1,3-transposition and 1,2-alkyl migration of tert-alkyl substituents to the enone β-carbon.