Related Experiment Video
Updated: Jun 12, 2026

Preparation and Reactivity of a Triphosphenium Bromide Salt: A Convenient and Stable Source of Phosphorus(I)
Published on: November 22, 2016
PyOxP and PyOxB: the Oxyma-based novel family of phosphonium salts
Ramon Subirós-Funosas1, Ayman El-Faham, Fernando Albericio
1Institute for Research in Biomedicine, Barcelona Science Park, Baldiri Reixac 10, 08028, Barcelona, Spain.
Abstract:
Recent studies described the great impact of a non-benzotriazolic family of coupling reagents based on ethyl 2-cyano-2-(hydroxyimino)acetate, Oxyma, as a powerful coupling methodology for peptide synthesis. Here we present the synthesis and evaluation of the derived phosphonium salts O-[(1-cyano-2-ethoxy-2-oxoethylidene)amino]-oxytri(pyrrolidin-1-yl) phosphonium hexafluorophosphate (PyOxP) and tetrafluoroborate (PyOxB). Both coupling reagents exhibited higher capacity to suppress racemization in various peptide models and enhanced solubility in DMF and DCM than benzotriazole-based reagents. In addition, the hexafluorophosphate analog PyOxP, combined excellent stability with outstanding efficiency in the assembly of demanding penta and decapeptides that include consecutive Aib residues. Cyclization models revealed the advantages of PyOxP, which rendered a higher percentage of cyclic material than other known potent phosphonium salts.
Related Concept Videos
Ion Exchange
¹H NMR: Pople Notation
A proton...
Diazonium Group Substitution: –OH and –H
Olefin Metathesis Polymerization: Ring-Opening Metathesis Polymerization (ROMP)
Preparation of Epoxides
Epoxides result from alkene oxidation, which can be achieved by a) air, b) peroxy acids, c) hypochlorous acids, and d) halohydrin cyclization.
Epoxidation with Peroxy Acids
Epoxidation of alkenes via oxidation with peroxy acids involves the conversion of a carbon–carbon double bond to an epoxide using the oxidizing agent meta-chloroperoxybenzoic acid, commonly known as MCPBA. Since the O–O bond of peroxy acids is very weak, the addition of electrophilic oxygen of peroxy acids to...
Organic Compounds
