Bandini, Marco; Melloni, Alfonso; Piccinelli, Fabio; Sinisi, Riccardo; Tommasi, Simona; Umani-Ronchi, Achille published an article on February 8 ,2006. The article was titled 《Highly Enantioselective Synthesis of Tetrahydro-β-Carbolines and Tetrahydro-γ-Carbolines Via Pd-Catalyzed Intramolecular Allylic Alkylation》, and you may find the article in Journal of the American Chemical Society.COA of Formula: C58H42N2O2P2 The information in the text is summarized as follows:
(2-Indolylmethylamino) or (3-indolylmethylamino)butadienyl carbonates such as I and a (pyrrolylmethylamino)butadienyl carbonate undergo enantioselective intramol. allylic alkylation reactions in the presence of tris(dibenzylideneacetone)palladium and nonracemic (diphenylphosphinobenzoyl)diamines such as II to yield nonracemic tetrahydro-β-carbolines, tetrahydro-γ-carbolines, and a pyrrolopyridine such as III (R = PhCH2) and IV (R = PhCH2) in 82-97% ee. (indolylmethylamino)butadienyl or (pyrrolylmethylamino)butadienyl carbonates such as I are prepared from indolecarboxaldehydes by imine formation and reduction, alkylation of the amines with bromobutenoate esters (or a bromobutenal), reduction of the ester or aldehyde with diisobutylaluminum hydride, and acylation with Me chlorocarbonate. A variety of ligands for the cyclocondensation are tried; diphenylphosphinobenzamides such as II give carbolines with the highest regioselectivities and enantioselectivities of the ligands tried. (indolylmethylamino)butadienyl carbonates substituted either on the indole or the butenyl moieties yield carbolines with similar enantio- and regioselectivities. An (E)-3-indolylmethylaminobutenol carbonate undergoes regio- and enantioselective allylic alkylation to yield a γ-carboline in 90% yield and 93% yield, while intramol. allylic alkylation of the corresponding (Z)-3-indolylmethylaminobutenol carbonate yields the opposite enantiomer in 65% yield and in 5% ee. The absolute configuration of III (R = PhCH2) is determined by X-ray crystallog. anal. of a β-carboline (-)-camphorsulfonamide derived from its enantiomer [the minor stereoisomer generated in the allylic alkylation which yields III (R = PhCH2)].(S)-N,N’-(1,1′-Binaphthalene]-2,2′-diyl)bis(2-diphenylphosphinobenzamide)(cas: 879505-38-1COA of Formula: C58H42N2O2P2) was used in this study.
(S)-N,N’-(1,1′-Binaphthalene]-2,2′-diyl)bis(2-diphenylphosphinobenzamide)(cas: 879505-38-1) belongs to chiral phosphine ligands. Nucleophilic phosphine catalysis often involves the formation of Lewis adducts, namely phosphonium (di)enolate zwitterions, as reaction intermediates. These intermediates are formed through nucleophilic attack of the phosphine catalysts at electron-poor nuclei (normally carbon atoms) and then proceed through several steps to form new chemical bonds. COA of Formula: C58H42N2O2P2
Referemce:
Phosphine ligand,
Chiral phosphines in nucleophilic organocatalysis