296238-72-7Relevant academic research and scientific papers
Mechanistic Studies and Expansion of the Substrate Scope of Direct Enantioselective Alkynylation of α-Ketiminoesters Catalyzed by Adaptable (Phebox)Rhodium(III) Complexes
Morisaki, Kazuhiro,Sawa, Masanao,Yonesaki, Ryohei,Morimoto, Hiroyuki,Mashima, Kazushi,Ohshima, Takashi
, p. 6194 - 6203 (2016/06/09)
Mechanistic studies and expansion of the substrate scope of direct enantioselective alkynylation of α-ketiminoesters catalyzed by adaptable (phebox)rhodium(III) complexes are described. The mechanistic studies revealed that less acidic alkyne rather than more acidic acetic acid acted as a proton source in the catalytic cycle, and the generation of more active (acetato-κ2O,O′)(alkynyl)(phebox)rhodium(III) complexes from the starting (diacetato)rhodium(III) complexes limited the overall reactivity of the reaction. These findings, as well as facile exchange of the alkynyl ligand on the (alkynyl)rhodium(III) complexes led us to use (acetato-κ2O,O′)(trimethylsilylethynyl)(phebox)rhodium(III) complexes as a general precatalyst for various (alkynyl)rhodium(III) complexes. Use of the (trimethylsilylethynyl)rhodium(III) complexes as precatalysts enhanced the catalytic performance of the reactions with an α-ketiminoester derived from ethyl trifluoropyruvate at a catalyst loading as low as 0.5 mol % and expanded the substrate scope to unprecedented α-ketiminophosphonate and cyclic N-sulfonyl α-ketiminoesters.
A new preparative method for the synthesis of diethyl 1-diazo-2,2,2- trifluoroethylphosphonate via an imino phosphonate
Karimova,Vorobyeva,Shchetnikov,Osipov
, p. 107 - 109 (2011/01/08)
A preparative method for the synthesis of diethyl 1-diazo-2,2,2- trifluoroethylphosphonate from trifluoroacetic anhydride and benzyl carbamate via diethyl 1-benzyloxycarbonylimino-2,2,2-trifluoroethylphosphonate is developed. Optimum conditions for the ch
