57767-11-0Relevant articles and documents
Regioselective Formation of Enol Esters from the Ruthenium-Catalyzed Markovnikov Addition of Carboxylic Acids to Alkynes
Jeschke, Janine,G?bler, Christian,Lang, Heinrich
, p. 476 - 484 (2016/01/25)
The ruthenium complexes [Ru(CO)2(P(p-C6H4-X)3)2(O2CPh)2] (1a, X = CF3; 1b, X = Cl; 1c, X = H; 1d, X = Me; 1e, X = OMe) were successfully applied in the regioselective Markovnikov addition of carboxylic acids to terminal alkynes, yielding valuable enol esters. Catalyst screening revealed a significant influence of phosphine's electronic nature on activity and selectivity. The highest activity was achieved with catalyst 1a, featuring the most electron-withdrawing phosphine ligand. Selectivity and activity could be further improved by the addition of catalytic amounts of AgOTf. Moreover, excellent selectivities with up to 99% of the Markovnikov product were achieved. The electronic influence of the substrates on the reaction rate was quantified by Hammett plots. By the use of electron-rich alkynes or highly acidic carboxylic acids, the reaction rate could be increased. Hence, the addition of highly acidic pentafluorobenzoic acid to electron-rich 4-methoxyphenylacetylene can even be carried out quantitatively at 25°C within 4 h. Furthermore, a broad range of simple as well as electronically or sterically challenging substrates could be isolated in good to excellent yields with high regioselectivity and under mild reaction conditions (25-70°C). The best reported activities and selectivities were obtained for the conversion of aromatic alkynes.
Copper-catalyzed enantioselective intramolecular alkene amination/intermolecular heck-type coupling cascade
Liwosz, Timothy W.,Chemler, Sherry R.
supporting information; experimental part, p. 2020 - 2023 (2012/03/12)
Enantioselective copper-catalyzed cyclization of γ- alkenylsulfonamides and a δ-alkenylsulfonamide in the presence of a range of vinyl arenes results in variously functionalized 2-substituted chiral nitrogen heterocycles via a formal alkene C-H functionalization process. Application of this reaction to the concise synthesis of a 5-HT7 receptor antagonist is demonstrated.
Mg-promoted carbon-acylation of aromatic aldehydes and ketones
Nishiguchi, Ikuzo,Sakai, Masahiro,Maekawa, Hirofumi,Ohno, Toshinobu,Yamamoto, Yoshimasa,Ishino, Yoshio
, p. 635 - 637 (2007/10/03)
Reductive cross-coupling of aromatic aldehydes and ketones with aliphatic acid chlorides promoted by Mg turnings in DMF at room temperature brought about efficient C-acylation to afford the corresponding α-acyloxy-α-aryl ketones in good yields. Treatment
