Sequential Pd 2 (dba) 3 Participated C-C Bond Cleavage of O -bromophenyl cyclobutanones/Michael Addition en route to Benzospirones

Abstract A tandem Pd 2 (dba) 3 participated C–C bond cleavage of O -bromophenyl cyclobutanone derivatives/Michael addition reaction sequence was realized. We disclosed the first intramolecular C–Br bond triggered ring opening reaction of arylcyclobutanones, distinct from related reports in which the reactions were initiated by arylboron, silane or unsaturated chemical motifs, among others. The in situ generated palladium species underwent ring expansion process leading to methyleneindanones, which further reacted with dba to provide benzospirones in one step.