Iridium Complex-Catalyzed Highly Selective Cross [2 + 2 + 2] Cycloaddition of Two Different Monoynes: 2:1 Coupling versus 1:2 Coupling
作者:Ryo Takeuchi、Yoshihiko Nakaya
DOI:10.1021/ol035330d
日期:2003.10.1
Highly selective cross [2 + 2 + 2] cycloaddition of two different monoynes is achieved by using a catalytic amount of [Ir(cod)Cl](2) 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.
Iridium Complex-Catalyzed Cross-Coupling Reaction of Terminal Alkynes with Internal Alkynesvia CH Activation of Terminal Alkynes
complex to produce a 1 : 1 adduct in high regio- and stereoselectivities. This reaction was extended to various combinations of terminal alkynes with internal alkynes such as alkynylesters and alkynyl aldehydes. The selectivity of the reaction was found to markedly depend on the ligands used. When dppe was used as a ligand, the 1 : 2cross-cyclotrimerization reaction took place to form substituted benzene