Sonogashira coupling of arenediazonium salts: discovery and developments

Abstract

Colourful chemistry: Arenediazonium salts represent efficient, common, easily available aryl surrogates from inexpensive anilines and show higher reactivity compare to aryl halides and triflates towards various crosscoupling reactions. We have disclosed the Sonogashira coupling of arenediazonium salts in 2010; afterward, several groups successfully developed various protocols for this reaction. This mini-review describes the discovery and progress of the alkynylation of arenediazonium salts in due time, highlights the strengths and weaknesses of each protocol.

Catalytic alkynylations through the activation of C-N bonds

“…54,55 The first Sonogashira coupling of arene diazonium salts utilizing a Pd-Au synergistic dual catalytic system has been successfully developed. 56,57 The coupling of arene diazonium salts with terminal alkynes was performed at room temperature omnipresence of carbene ligand bis-2,6-diisopropylphenyl dihydroimidazolium chloride (IPr NHC) (5 mol %) and base DBMP(2,6-Di-tert-butyl-4-methylpyridine) in acetonitrile using AuCl as a co-catalyst along with PdCl2 as catalyst. The synthetic efficiency of this reaction was investigated with a range of electronically and structurally varied arene diazonium salts and terminal alkynes.…”

Aerobic bimetallic catalysis for oxy-alkynylation of allenes

“…1 As we know, Sonogashira coupling reactions of electrophilic organic halides with terminal alkynes have been established as one of the most efficient ways for the syntheses of substituted alkynes (Scheme 2a). 2,3 We envisioned a concept of the coupling reaction of cyclo alkenyl or alkyl metallic species in situ formed via the cyclic nucleometalation of unsaturated hydrocarbons with a nucleophilic functionality with terminal alkynes for the efficient synthesis of alkynyl-substituted cyclic skeleton (Scheme 2b), which should be a platform reaction for the selective synthesis of alkynyl or ( Z ) or ( E )-alkenyl-substituted cyclic compounds listed in Scheme 1. The key here is the match of the reactivity of these two species, the regeneration of the catalyst, Glaser–Hay coupling reaction of the terminal alkynes applied, and the regioselectivity of the cyclization reaction.…”