Recent advances in Sonogashira reactions

Abstract

The coupling of aryl or vinyl halides with terminal acetylenes catalysed by palladium and other transition metals, commonly termed as Sonogashira cross-coupling reaction, is one of the most important and widely used sp(2)-sp carbon-carbon bond formation reactions in organic synthesis, frequently employed in the synthesis of natural products, biologically active molecules, heterocycles, molecular electronics, dendrimers and conjugated polymers or nanostructures. This critical review focuses on developments in the Sonogashira reaction achieved in recent years concerning catalysts, reaction conditions and substrates (352 references).

Rigidified A3 Adenosine Receptor Agonists: 1-Deazaadenine Modification Maintains High in Vivo Efficacy

“…16,17 Ester aminolysis followed by nucleophilic substitution of the 6-chloro with an alkyl or cycloalkyl amine gave the N 6 -substituted intermediates 8. The C2 alkynyl group was installed by a Sonogashira reaction, 19 followed by isopropylidene deprotection in aqueous acid to provide 1-deaza nucleosides 19−22. The 1-deaza C2-triazolyl derivative 29 was prepared by a modification of this route to include a click [3 + 2] cycloaddition step as shown in Scheme 2.…”

Alkynylation with Hypervalent Iodine Reagents

“…With aliphatic groups, the migration is slow, and C-H insertion in either the substrate or the alkyne substituent is observed to give 10 or 11. In the case of the alkynylation, the use of fast mi- 6 grating silyl or hydrogen substituents is especially relevant, as it gives access to versatile terminal acetylenes as products [36].…”

“…This is not surprising, as the terminal C-H bond of alkynes is highly acidic due to the sp-hybridization, and the formation of acetylide anions is consequently facile. Methods such as addition of acetylides to carbonyl compounds [4] or the Sonogashira cross coupling [5,6] are now routinely used for the synthesis of alkynes and are highly reliable. In stark contrast, the addition of alkynes onto nucleophiles requires an inversion of their inherent reactivity (an Umpolung, Scheme 2.1, B).…”

Synthesis of Substituted Naphtho‐Ferrocenes via a Gold(I)‐Catalyzed Intramolecular 6‐endo‐Dig Cyclization

“…Herein, we reported an efficient gold-catalyzed [5,8] intramolecular 6-endo-dig cyclization of 1-ferrocenyl-2-(1-alkynyl)benzenes which were easily prepared via palladium-catalyzed Negishi coupling [9] and Sonogashira coupling [10,11] reaction (Scheme 2), to give structurally diverse naphtho-ferrocenes derivatives under very mild reaction conditions (Scheme 1c). …”