Wang, Cong-Shuai; Wei, Liang; Fu, Cong; Wang, Xin-Heng; Wang, Chun-Jiang published their research in Organic Letters in 2021. The article was titled 《Asymmetric Synthesis of Axially Chiral Naphthyl-C3-indoles via a Palladium-Catalyzed Cacchi Reaction》.Safety of (S)-5,5′-Bis(diphenylphosphino)-4,4′-bi-1,3-benzodioxole The article contains the following contents:
Atropoisomeric biaryl motifs are widely found in natural products and bioactive compounds as well as chiral catalysts and ligands. Various efficient approaches have been disclosed for the construction of chiral six-six biaryl skeletons. In contrast, the enantioselective synthesis of axially chiral arylindoles through the strategy of de novo construction, other than the asym. functionalization of indoles, remain a challenging task. Herein authors report an efficient Pd(0)/(S)-Segphos-catalyzed atroposelective Cacchi reaction of 2-alkynylanilines with sterically congested naphthyl halides, which afforded an array of naphthyl-C3-indoles in high yields with good to excellent atroposelectivities. The addition of water and the modulation of the manipulation procedure by premixing the palladium complex and the naphthyl halide were the keys to success. The conformational stability of the obtained axially chiral naphthyl-C3-indole containing a synthetically more-valuable free NH moiety is revealed through kinetic experiments The experimental process involved the reaction of (S)-5,5′-Bis(diphenylphosphino)-4,4′-bi-1,3-benzodioxole(cas: 210169-54-3Safety of (S)-5,5′-Bis(diphenylphosphino)-4,4′-bi-1,3-benzodioxole)
(S)-5,5′-Bis(diphenylphosphino)-4,4′-bi-1,3-benzodioxole(cas: 210169-54-3) is a chelating ligand used to prepare coordination complex catalysts, such as its use in Pd catalysts for the enantioselective synthesis of spiro- or benzofused hetereocycles with exocyclic olefins via enantioselective intramolecular dearomative Heck reaction of indoles, benzofurans, pyrroles and furans.Safety of (S)-5,5′-Bis(diphenylphosphino)-4,4′-bi-1,3-benzodioxole
Referemce:
Phosphine ligand,
Chiral phosphines in nucleophilic organocatalysis