Synthesis and Rhodium(I)-Catalyzed Annulative Cleavage of Bicy-clo[1.1.0]butyl Dihydroquinolines and Dihydropyridines

Bicyclo[1.1.0]butane (BCB)-containing compounds are a highly strained class of reagents that feature a unique chemical reactivity, trig-gering “strain-release” reaction cascades, and provide unique products with considerable utility in the drug discovery field. The C-C bridgehead bond of BCB’s two fused cyclopropane rings holds significant π-character, allowing BCB-containing compounds to react with nucleophiles, electrophiles, radicals, π-systems, and carbenes. Herein, we reported the synthesis of new BCBs by the trapping of nu-cleophilic intermediates with quaternary ammonium ions derived from quinolines and pyridines. The resulting BCBs are then converted with high regioselectivity to unprecedented fused heterocycles in a rhodium(I)-catalyzed annulative rearrangement.