Xiao, Xiong; Yu, Zhi-Xiang published the artcile< Co-Catalyzed Asymmetric Intramolecular [3+2] Cycloaddition of Yne-Alkylidenecyclopropanes and its Reaction Mechanism>, Name: (S)-(-)-2,2′-Bis(diphenylphosphino)-5,5′,6,6′,7,7′,8,8′-octahydro-1,1′-binaphthyl, the main research area is alkylidenecyclopropanes cobalt catalyst enantioselective cycloaddition mechanism DFT; carbocycle stereoselective preparation; alkylidenecyclopropanes; carbocycles; cobalt; homogeneous catalysis; reaction mechanisms.
Developing new transition metal-catalyzed asym. cycloadditions for the synthesis of five-membered carbocycles (FMCs) is a research frontier in reaction development due to the ubiquitous presence of chiral FMCs in various functional mols. Reported here is our discovery of a highly enantioselective intramol. [3+2] cycloaddition of yne-alkylidenecyclopropanes (yne-ACPs) to bicyclo[3.3.0]octadiene, e.g., I, and bicyclo[4.3.0]nonadiene mols. using a cheap Co catalyst and com. available chiral ligand (S)-Xyl-BINAP. This reaction avoids the use of precious Pd and Rh catalysts, which are usually the choices for [3+2] reactions with ACPs. The enantiomeric excess in the present reaction can be up to 92%. Cationic cobalt(I) species was suggested by experiments as the catalytic species. DFT calculations showed that this [3+2] reaction starts with oxidative cyclometallation of alkyne and ACP, followed by ring opening of the cyclopropyl (CP) group and reductive elimination to form the cycloadduct. This mechanism is different from previous [3+2] reactions of ACPs, which usually start from CP cleavage, not from oxidative cyclization.
Chemistry – A European Journal published new progress about [3+2] Cycloaddition reaction catalysts. 139139-93-8 belongs to class chiral-phosphine-ligands, and the molecular formula is C44H40P2, Name: (S)-(-)-2,2′-Bis(diphenylphosphino)-5,5′,6,6′,7,7′,8,8′-octahydro-1,1′-binaphthyl.
Referemce:
Phosphine ligand,
Chiral phosphine ligands in asymmetric synthesis. Molecular structure and absolute configuration of (1,5-cyclooctadiene)-(2S,3S)-2,3-bis(diphenylphosphino)butanerhodium(I) perchlorate tetrahydrofuran solvate