609818-07-7Relevant academic research and scientific papers
Azomethine Ylides from Nitrones: Using Catalytic nBuLi for the Totally Stereoselective Synthesis of trans-2-Alkyl-3-oxazolines
Juste-Navarro, Veronica,Delso, Ignacio,Tejero, Tomás,Merino, Pedro
, p. 11527 - 11532 (2016)
The cycloaddition of azomethine ylide N-oxides (nitrone ylides) with aldehydes provides 3-oxazolines in a completely stereoselective manner in the presence of a catalytic amount of n-butyllithium. The process involves an initial nucleophilic attack on the aldehyde, followed by intramolecular oxygen addition to the nitrone moiety and lithium-assisted elimination of water, regenerating the catalytic species. Various Li-based catalytic systems are possible and the in situ generated water is required for continuing the catalytic cycle. The best results are observed with 20 mol % of n-butyllithium, whereas the use of stoichiometric amounts inhibit the rate of catalysis. Experimental, spectroscopic, and computational mechanistic studies have provided evidence of lithium-ion catalysis and rationalized several competing catalytic pathways.
Stereoselective 1,3-dipolar cycloadditions of nitrones derived from amino acids. Asymmetric synthesis of N-(alkoxycarbonylmethyl)-3-hydroxypyrrolidin-2- ones Dedicated to Professor Giovanni Romeo on occasion of his 70th birthday
Merino, Pedro,Greco, Graziella,Tejero, Tomás,Hurtado-Guerrero, Ramon,Matute, Rosa,Chiacchio, Ugo,Corsaro, Antonino,Pistarà, Venerando,Romeo, Roberto
, p. 9381 - 9390 (2013/10/08)
Diastereoselective asymmetric 1,3-dipolar cycloadditions of N-(alkoxycarbonylmethyl) nitrones derived from glycine, alanine and phenylalanine have been studied both experimentally and theoretically. Asymmetric induction is evaluated by either introducing
