Phosphonium coupling

In organic chemistry, phosphonium coupling is a cross-coupling reaction for organic synthesis. It is a mild, efficient, chemoselective and versatile methodology for the formation of C–C, C–N, C–O, and C–S bond of unactivated and unprotected tautomerizable heterocycles. The method was originally reported in 2004.[1] The C–OH bond of a tautomerizable heterocycle is activated with a phosphonium salt (PyBroP, PyBOP, BroP, or BOP), and subsequent functionalization with either a nucleophile through SNAr displacement or an organometallic through transition metal catalyzed cross coupling reaction. The in situ activation of the C-OH bond in phosphonium coupling has been applied to cross coupling reactions of tautomerizable heterocycles and arenols using other types of activating reagents.[2][3]

Phosphonium coupling generates in situ a pseudo aryl or heteroaryl halide (the intermediate phosphonium species), which subsequently reacts with its coupling partner.[4][5][6][7][8][9]


  1. ^ Kang, Fu-An; Kodah, Jason; Guan, Qunying; Li, Xiaobing; Murray, William V., Efficient conversion of Biginelli 3,4-dihydropyrimidin-2(1H)-one to pyrimidines via PyBroP-mediated coupling, Journal of Organic Chemistry (2005), 70(5), 1957-1960. doi:10.1021/jo040281j
  2. ^ Pon, Richard T.; Yu, Shuyuan; Sanghvi, Yogesh S. (1999). "Rapid Esterification of Nucleosides to Solid-Phase Supports for Oligonucleotide Synthesis Using Uronium and Phosphonium Coupling Reagents". Bioconjugate Chemistry. 10 (6): 1051–1057. doi:10.1021/bc990063a. PMID 10563775.
  3. ^ Kang, Fu-An (2015). Recent Progress of Phosphonium Coupling in Heterocyclic and Medicinal Chemistry. Progress in Heterocyclic Chemistry. Vol. 27. pp. 29–59. doi:10.1016/B978-0-08-100024-3.00002-7. ISBN 9780081000243.
  4. ^ Chinchilla, Rafael; Najera, Carmen, Recent advances in Sonogashira reactions, Chemical Society Reviews (2011), 40(10), 5084-5121. doi:10.1039/c1cs15071e
  5. ^ Sellars, Jonathan D.; Steel, Patrick G., Transition metal-catalysed cross-coupling reactions of P-activated enols, Chemical Society Reviews (2011), 40(10), 5170-5180. doi:10.1039/c1cs15100b
  6. ^ Li, Bi-Jie; Yu, Da-Gang; Sun, Chang-Liang; Shi, Zhang-Jie, Activation of "Inert" Alkenyl/Aryl C=O Bond and Its Application in Cross-Coupling Reactions, Chemistry--A European Journal (2011), 17(6), 1728-1759. doi:10.1002/chem.201002273
  7. ^ Katritzky, Alan R.; Rachwal, Stanislaw, Synthesis of heterocycles mediated by benzotriazole. 2. Bicyclic systems, Chemical Reviews (Washington, DC, United States) (2011), 111(11), 7063-7120. doi:10.1021/cr200031r
  8. ^ Ackermann, Lutz, Carboxylate-Assisted Transition-Metal-Catalyzed C-H Bond Functionalizations: Mechanism and Scope, Chemical Reviews (Washington, DC, United States) (2011), 111(3), 1315-1345. doi:10.1021/cr100412j
  9. ^ Allen, Anna E.; MacMillan, David W. C., Synergistic catalysis: A powerful synthetic strategy for new reaction development, Chemical Science (2012), 3(3), 633-658. doi:10.1039/c2sc00907b