Palladium-catalyzed allene synthesis enabled by β-hydrogen elimination from sp2-carbon

Abstract The rational design based on a deep understanding of the present reaction mechanism is an important, viable approach to discover new organic transformations. β -Hydrogen elimination from palladium complexes fundamental in catalysis. Normally, eliminated β- hydrogen has be attached sp 3 -carbon. We envision that 2 -carbon possible by using thoroughly designed systems, which may offer strategy for preparation allenes. Here, we describe palladium-catalyzed cross-coupling 2,2-diarylvinyl bromides and diazo compounds, where -vinylic allylic intermediate proposed key step. Both aryl carbonyl compounds N -tosylhydrazones are competent carbene precursors this reaction. explored control experiments, KIE studies DFT calculations.