1057237-56-5Relevant academic research and scientific papers
Stereoselective Synthesis of Tetrasubstituted Alkenes via a Cp*CoIII-Catalyzed C?H Alkenylation/Directing Group Migration Sequence
Ikemoto, Hideya,Tanaka, Ryo,Sakata, Ken,Kanai, Motomu,Yoshino, Tatsuhiko,Matsunaga, Shigeki
, p. 7156 - 7160 (2017)
A highly atom economical and stereoselective synthesis of tetrasubstituted α,β-unsaturated amides was achieved by a Cp*CoIII-catalyzed C?H alkenylation/directing group migration sequence. A carbamoyl directing group, which is typically removed after C?H functionalization, worked as an internal acylating agent and migrated onto the alkene moiety of the product. The directing group migration was realized with the Cp*CoIII catalyst, while a related Cp*RhIII catalyst did not promote the migration process. The product was further converted into two types of tricyclic compounds, one of which had fluorescent properties.
Ruthenium(II)-Catalyzed Redox-Neutral [3+2] Annulation of Indoles with Internal Alkynes via C-H Bond Activation: Accessing a Pyrroloindolone Scaffold
Xie, Yanan,Wu, Xiaowei,Li, Chunpu,Wang, Jiang,Li, Jian,Liu, Hong
, p. 5263 - 5273 (2017/05/24)
Ru(II)-catalyzed redox-neutral [3+2] annulation reactions of N-ethoxycarbamoyl indoles and internal alkynes via C-H bond activation are reported. This method features a broad internal alkyne scope, including various aryl/alkyl-, alkyl/alkyl-, and diaryl-substituted alkynes, good to excellent regioselectivity, diverse functional group tolerance, and mild reaction conditions. The N-ethoxycarbamoyl directing group, temperature, CsOAc, and ruthenium catalyst proved to be crucial for conversion and high regioselectivity. Additionally, preliminary mechanistic experiments were conducted, and a possible mechanism was proposed.
Pyrroloindolone synthesis via a Cp*CoIII-catalyzed redox-neutral directed C-H alkenylation/annulation sequence
Ikemoto, Hideya,Yoshino, Tatsuhiko,Sakata, Ken,Matsunaga, Shigeki,Kanai, Motomu
supporting information, p. 5424 - 5431 (2014/05/06)
A unique synthetic utility of a Cp*CoIII catalyst in comparison with related Cp*RhIII catalysts is described. A C2-selective indole alkenylation/annulation sequence proceeded smoothly with catalytic amount of a [Cp*CoIII(C6H 6)](PF6)2 complex and KOAc. Intramolecular addition of an alkenyl-Cp*Co species to a carbamoyl moiety gave pyrroloindolones in 58-89% yield in one pot. Clear difference was observed between the catalytic activity of the Cp*CoIII complex and those of Cp*RhIII complexes, highlighting the unique nucleophilic activity of the organocobalt species. The Cp*CoIII catalysis was also suitable for simple alkenylation process of N-carbamoyl indoles, and broad range of alkynes, including terminal alkynes, were applicable to give C2-alkenylated indoles in 50-99% yield. Mechanistic studies on C-H activation step under Cp*CoIII catalysis with the aid of an acetate unit as well as evaluation of the difference between organo-Co III species and organo-RhIII species are also described.
