Synthesis of Unsymmetrical 4,4′-Bipyridines through Base-Mediated Cross-Coupling between 4-Pyridyl Phosphonium Salts

Organic Letters 2026

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Authors: B K Paul, Malekul Islam, Fadil Faizal Mannighayil, Suman De Sarkar
DOI: 10.1021/acs.orglett.5c05284
Cited by: 1
References: 49

Abstract

Syntheses of unsymmetrical 4,4′-bipyridines were achieved through base-mediated cross-couplings of diverse 4-pyridyl phosphonium salts. This transition-metal- and oxidant-free protocol operates under mild conditions and tolerates a broad range of functional groups. Subsequent derivatization of the bipyridine products enabled the selective preparation of viologens and other valuable aromatic scaffolds. Mechanistic studies indicate the formation of an anionic pyridyl intermediate, which undergoes C–C bond formation through phosphorus ligand coupling or an S N Ar mechanism.

Fields of Study & Subjects

Catalytic C–H Functionalization Methods Catalytic Cross-Coupling Reactions Organophosphorus compounds synthesis

Publication details

Journal / source
Organic Letters
Publisher
American Chemical Society (ACS)
Volume
28
Issue
6
Pages
2038–2043
Publication date
29 January 2026
Language
EN