《Enantioselective Synthesis of Triple Helicenes by Cross-Cyclotrimerization of a Helicenyl Aryne and Alkynes via Dynamic Kinetic Resolution》 was written by Yubuta, Ayaka; Hosokawa, Tomoka; Gon, Masayuki; Tanaka, Kazuo; Chujo, Yoshiki; Tsurusaki, Akihiro; Kamikawa, Ken. Electric Literature of C51H42O3Pd2 And the article was included in Journal of the American Chemical Society in 2020. The article conveys some information:
Optically active triple helicenes were prepared via a palladium-catalyzed enantioselective cross-cyclotrimerization of two helicenyl arynes, which are generated in situ from, with dialkylacetylene dicarboxylate. Enantiomeric ratios (e.r.) of up to 98 : 2 were obtained when using dimethylacetylene dicarboxylate and (S)-QUINAP as the alkyne and chiral ligand, resp. The absolute stereochem. was revealed to be (M,P,M) by a single-crystal x-ray diffraction anal. Kinetic studies of the racemization of enantiomerically pure triple helicene at elevated temperatures were conducted based on a high-performance liquid chromatog. (HPLC) anal. The activation energy for the rac-emization was found to be 29.1 kcal mol-1. D. functional theory (DFT) calculations revealed that the palladium-catalyzed enanti-oselective cross-cyclotrimerization reactions proceed via the dynamic kinetic resolution (DKR) of a five-membered palladacycle with two [5]helicenes. Several initially formed stereoisomers eventually isomerize into the most thermodynamically stable palladacycle intermediate (M,P,M)- by inversion of the [5]helicenyl moiety. Then, the insertion of dialkylacetylene dicarboxylate to palladacycle to form (M,P,M)-, followed by a reductive elimination, leads to the formation of (M,P,M)- in a stereoselective manner. The optical properties of triple helicenes were studied by CD (CD) and circularly polarized luminescence (CPL).Tris(dibenzylideneacetone)dipalladium(0)(cas: 51364-51-3Electric Literature of C51H42O3Pd2) was used in this study.
Tris(dibenzylideneacetone)dipalladium(0)(cas: 51364-51-3) is used in the preparation of semiconducting polymers processed from nonchlorinated solvents into high performance thin film transistors.Electric Literature of C51H42O3Pd2It is used as catalyst for the synthesis of epoxides, alpha-arylation of ketones, in combination with BINAP for the asymmetric heck arylation of olefins, site-selective benzylic sp3 palladium-catalyzed direct arylation and homoallylic diamination of terminal olefins.
Referemce:
Metal catalyst and ligand design,
Ligand Template Strategies for Catalyst Encapsulation – NCBI