1,4-Pd Migration-Enabled Synthesis of Fused 4-Membered Rings.

1,4-Palladium migration has been widely used for the functionalization of remote C-H bonds. However, this mechanism has been limited to aryl halide precursors. This work reports an unprecedented Pd-catalyzed cyclobutanation protocol producing valuable fused cyclobutanes starting from cycloalkenyl (pseudo)halides.

Effect of α-Substitution on the Reactivity of C(sp)-H Bonds in Pd-Catalyzed C-H Arylation.

We report mechanistic studies on the reactivity of different α-substituted C(sp)-H bonds, -CHR (R = H, Me, COMe, CONMe, OMe, and Ph, as well as the cyclopropyl and isopropyl derivatives -CH(CH) and -CHMe) in the context of Pd-catalyzed C(sp)-H arylation. Primary kinetic isotope effects, /, were determined experimentally for R = H (3.2) and Me (3.