Rhodium(I)‐Catalyzed Intramolecular [5+2] Cycloaddition Reactions of Alkynes and Allenylcyclopropanes: Construction of Bicyclo[5.4.0]undecatrienes and Bicyclo[5.5.0]dodecatrienes

Come on allene: The [{RhCl(CO)2}2]- or [{RhCl(CO)dppp}2]-catalyzed intramolecular [5+2] cycloaddition of alkyne-allenylcyclopropanes under mild conditions affords the bicyclo[5.4.0]undecatriene or the larger bicyclo[5.5.0]dodecatriene frameworks (see scheme; dppp=1,3-bis(diphenylphosphino)propane).