Iridium Complex-Catalyzed Highly Selective Cross [2 + 2 + 2] Cycloaddition of Two Different Monoynes:  2:1 Coupling versus 1:2 Coupling Ryo Takeuchi Yoshihiko Nakaya 10.1021/ol035330d.s001 https://acs.figshare.com/articles/journal_contribution/Iridium_Complex-Catalyzed_Highly_Selective_Cross_2_2_2_Cycloaddition_of_Two_Different_Monoynes_2_1_Coupling_versus_1_2_Coupling/3748155 Highly selective cross [2 + 2 + 2] cycloaddition of two different monoynes is achieved by using a catalytic amount of [Ir(cod)Cl]<sub>2</sub> and ligand. The ligand had a considerable effect on the reaction. When 1,2-bis(diphenylphosphino)ethane was used, two molecules of dimethyl acetylenedicarboxylate (DMAD) reacted with one molecule of a monoyne to give the 2:1 coupling product. When 1,2-bis(dipentafluorophenylphosphino)ethane was used instead of dppe, one molecule of DMAD reacted with two molecules of a monoyne to give the 1:2 coupling product. 2003-09-06 00:00:00 DMAD molecule bi monoyne ligand dimethyl acetylenedicarboxylate