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Alexander Fernandez de la Torre

Catalysis 2022
Alexander Fernandez de la Torre, Speaker at Catalysis Conference
University of Concepcion, Chile
Title : Combining Organocatalysis and Multicomponent reactions: A sequential synthesis of Sec-containing peptides and dehydropeptides


The efficient design, scalable synthesis of biologically relevant compounds with high structural similarity to natural products remains a challenge to chemical synthesis areas. Metal transition catalysts have been extensively employed for the synthesis of bioactive compounds.1 However, the combination of metal-free asymmetric methodologies like Organocatalysis with Isocyanide-based Multicomponent reactions (IMCRs) is a new trend to produce natural and natural-like compounds.2 The asymmetric aminocatalytic functionalization of aldehydes - via enamine mechanism - followed by IMCRs, provides a convergent and stereoselective way to obtain in one-pot manner different scaffolds (e.g., hydroquinolines, cyclopentenes, peptoids and depsipeptides).2 These compounds can be accessed with high economy atoms, good yields, excellent stereo and regioselectivity, and a high degree of scaffold diversity. The current work is directly related to the merging of Organocatalytic and IMCRs reactions to obtain novel natural-like enantioenriched selenocysteine N-alkylated peptides and also dehydropeptides under mild conditions.  The synthetic protocol to the access of selenocysteine N-alkylated peptides comprises the organocatalytic asymmetric insertion of phenylselenium into aliphatic aldehyde moiety followed by the classic Ugi four-component reaction (Ugi-4CR) under mild conditions.  After further optimization, selenocysteine compounds were obtained with up to 98:2 e.r., in good yield, as determined by chiral ultra-performance convergence chromatography (UPC2) analysis. We next study the oxidative-elimination of the phenylselenocysteine group to access some dehydropeptides containing ?Abu and ?Phe with high regioselectivity (Scheme 1). We demonstrated by 1D and 2D NMR spectroscopic analysis that Z alkene and cis-rotamer preferably formed for all synthesized compounds


Dr. Alexander F. de la Torre received his B.Sc. and M.Sc. degrees in Chemistry from the University of Havana (Cuba). He then joined the research group of Prof. Marcio W. Paixão at the Center of Excellence for Research in Sustainable Chemistry, Federal University of São Carlos (Brazil). He received his Ph.D. degree in 2015 at the same institution. After a postdoctoral CNPq fellowship at the same institution, he moved to Chile and obtained a postdoctoral FONDECYT fellowship and the position of Assistant Professor at the University of Concepcion (Chile). He has published more than 25 research articles in SCI(E) journals.