1029555-13-2Relevant academic research and scientific papers
Azavinylidenephosphoranes: A Class of Cyclic Push–Pull Carbenes
Lavigne, Florie,Kazzi, Aimée El,Escudié, Yannick,Maerten, Eddy,Kato, Tsuyoshi,Saffon-Merceron, Nathalie,Branchadell, Vicen?,Cossío, Fernando P.,Baceiredo, Antoine
, p. 12528 - 12536 (2014)
The synthesis of a novel family of cyclic push–pull carbenes, namely, azavinylidene phosphoranes, is described. The methodology is based on a formal [3+2] cycloaddition between terminal alkynes and phosphine–imines followed by an oxidation/deprotonation step. Carbenes 6, obtained by simple deprotonation, exhibit typical transient carbene reactivity like the intramolecular C H insertion reaction and a pronounced ambiphilic character exemplified by [2+1] cycloaddition with electron-poor methyl acrylate. Owing to the cyclic structure, carbenes 6 also exhibit an excellent coordination ability toward transition metals. RhIcomplex 10 was obtained in excellent yield and was fully characterized by multinuclear NMR spectroscopy and X-ray crystallography. The corresponding RhI–carbonyl complex was also prepared; this indicates that carbenes 6 belong to the strongest σ-donating ligands to date. DFT calculations confirmed the high σ-donation ability of 6 and their classification as push–pull carbenes with a relatively small singlet–triplet energy gap of 23.2–24.3 kcal mol?1.
Novel N-phosphonio imine-catalyzed epoxidation reactions
Prieur, David,El Kazzi, Aimee,Kato, Tsuyoshi,Gornitzka, Heinz,Baceiredo, Antoine
supporting information; experimental part, p. 2291 - 2294 (2009/05/11)
(Chemical Equation Presented) A new type of acyclic N-phosphonio imine catalyst for selective epoxidations has been synthesized. The activity of these imine catalysts can easily be modulated by varying its substituents. The substituent attached to the imine nitrogen atom is particularly important for an efficient oxygen transfer.
