PyBrOP

PyBroP is a phosphonium salt used in peptide coupling chemistry, similar to PyCloP^[1]. PyBroP has the advantages of high efficiency, high yield, no diastereoisomerization and fast reaction rate in the coupling of N-methylated amino acids and α,α-disubstituted amino acids^[2]. PyBroP is a derivative of the phosphonium coupling reagent BOP, but contains pyrrolidine in the place of dimethylamine in BOP^[3]. PyBroP was developed as an alternative to the BOP reagent to avoid the release of toxic HMPA during the activation step^{[4. 5]}.

References:
[1] Coste J, Frerot E, Jouin P. Coupling N-methylated amino acids using PyBroP and PyCloP halogenophosphonium salts: mechanism and fields of application[J]. The Journal of Organic Chemistry, 1994, 59(9): 2437-2446.
[2] Humphrey J M, Chamberlin A R. Chemical synthesis of natural product peptides: coupling methods for the incorporation of noncoded amino acids into peptides[J]. Chemical Reviews, 1997, 97(6): 2243-2266.
[3] El-Faham A, Albericio F. Peptide coupling reagents, more than a letter soup[J]. Chemical reviews, 2011, 111(11): 6557-6602.
[4] Han S Y, Kim Y A. Recent development of peptide coupling reagents in organic synthesis[J]. Tetrahedron, 2004, 60(11): 2447-2467.
[5] Valeur E, Bradley M. Amide bond formation: beyond the myth of coupling reagents[J]. Chemical Society Reviews, 2009, 38(2): 606-631.

PyBroP是一种用于肽偶联化学的鏻盐，类似于PyCloP^[1]。PyBroP在N-甲基化氨基酸和α，α-二取代氨基酸的偶联中具有高效率、产量高、无差向异构化和反应速率快等优点^[2]。PyBroP是鏻偶联试剂BOP的衍生物，但含有吡咯烷部分代替BOP的二甲胺^[3]。PyBroP是作为BOP试剂的替代品开发的，可避免在活化步骤中释放有毒的HMPA^{[4. 5]}。