Yenthel Verhaegen

Abstract

Iron- and cobalt-catalyzed Sonogashira coupling reactions are becoming central areas of research in organic synthesis. Owing to their significant importance in the formation of carbon–carbon bonds, numerous green and nanoparticle protocols have emerged during the past decades. The non-toxic and inexpensive nature of catalysts gained much attention in recent times. In this context, their catalytic nature and activity in Sonogashira coupling reactions were well explored and compared. Most importantly, one of the highlights of this review is the emphasis given to green strategies. This is the first review on iron- and cobalt-catalyzed Sonogashira coupling reactions which comprehends literature up to 2020.

Beilstein J. Org. Chem. 2022, 18, 262–285. doi:10.3762/bjoc.18.31

The first mechanochemical strategy for highly chemoselective, solvent-free palladium-catalyzed cross-coupling of amides by N−C bond activation is reported. The protocol advances the biorelevant amide bond cross-coupling manifold to solid-state solventless cross-coupling methods.

Abstract

Although cross-coupling reactions of amides by selective N−C cleavage are one of the most powerful and burgeoning areas in organic synthesis due to the ubiquity of amide bonds, the development of mechanochemical, solid-state methods remains a major challenge. Herein, we report the first mechanochemical strategy for highly chemoselective, solvent-free palladium-catalyzed cross-coupling of amides by N−C bond activation. The method is conducted in the absence of external heating, for short reaction time and shows excellent chemoselectivity for σ N−C bond activation. The reaction shows excellent functional group tolerance and can be applied to late-stage functionalization of complex APIs and sequential orthogonal cross-couplings exploiting double solventless solid-state methods. The results extend mechanochemical reaction environments to advance the chemical repertoire of N−C bond interconversions to solid-state environmentally friendly mechanochemical methods.

Abstract

Diverse strategies for the efficient and attractive synthesis of a wide variety of relevant 1,4,5-trisubstituted 1,2,3-triazole molecules are reported. The synthesis of this category of diverse fully functionalized 1,2,3-triazoles has become a necessary and unique research subject in modern synthetic organic key transformations in academia, pharmacy, and industry. The current review aims to cover a wide literature survey of numerous synthetic strategies. Recent reports (2017–2021) in the field of 1,4,5-trisubstituted 1,2,3-triazoles are emphasized in this current review.

Beilstein J. Org. Chem. 2021, 17, 1600–1628. doi:10.3762/bjoc.17.114

1‐Hydroxybenzotriazole (HOBt) was identified as an efficient nucleophilic catalyst to activate sulfonyl fluorides and fluorosulfates for a broad‐spectrum, catalytic amidation to prepare various sulfonamides and sulfamates, including sterically hindered ones. The potential of this methodology in medicinal and process chemistry has been demonstrated by multidecagram‐scale synthesis of an amantadine derivative and synthesis of the drug Fedratinib.

Abstract

A broad‐spectrum, catalytic method has been developed for the synthesis of sulfonamides and sulfamates. With the activation by the combination of a catalytic amount of 1‐hydroxybenzotriazole (HOBt) and silicon additives, amidations of sulfonyl fluorides and fluorosulfates proceeded smoothly and excellent yields were generally obtained (87–99 %). Noticeably, this protocol is particularly efficient for sterically hindered substrates. Catalyst loading is generally low and only 0.02 mol % of catalyst is required for the multidecagram‐scale synthesis of an amantadine derivative. In addition, the potential of this method in medicinal chemistry has been demonstrated by the synthesis of the marketed drug Fedratinib via a key intermediate sulfonyl fluoride 13. Since a large number of amines are commercially available, this route provides a facile entry to access Fedratinib analogues for biological screening.

Synlett
DOI: 10.1055/s-0037-1610766

Copper-catalyzed reactions of N-propargyl-N-(2-iodoaryl)amides with sodium azide have been developed, providing a novel and efficient method for the synthesis of [1,2,3]triazolo[1,5-a]quinoxaline compounds under mild conditions in moderate yields by tandem copper-catalyzed azide-alkyne cycloaddition and Ullmann-type coupling.
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Abstract

Amino- and polyaminophthalazinones were synthesized by the palladium‐catalyzed amination (alkyl- and arylamines, polyamines) of 4-bromophthalazinones in good yields. The coordinating properties of selected aminophthalazinones towards Cu(II) ions were investigated and the participation of the nitrogen atoms in the complexation of the metal ion was shown. A biological screening of the potential cytotoxicity of selected synthesized compounds on HT-29 and PC-3 cell lines, as well as on the L-929 cell line, proved that some amino derivatives of phthalazinone show interesting anticancer activities. The detailed synthesis, spectroscopic data, and biological assays are reported.

Beilstein J. Org. Chem. 2021, 17, 558–568. doi:10.3762/bjoc.17.50

Abstract

The rhodium-catalyzed transannulation of N-perfluoroalkyl-1,2,3-triazoles with aromatic and aliphatic terminal alkynes under microwave heating conditions afforded N-perfluoroalkyl-3,4-disubstituted pyrroles (major products) and N-fluoroalkyl-2,4-disubstituted pyrroles (minor products). The observed selectivities in the case of the reactions with aliphatic alkynes were high.

Beilstein J. Org. Chem. 2021, 17, 504–510. doi:10.3762/bjoc.17.44