Gwénaëlle Hervé

Palladium-catalyzed Suzuki reaction in aqueous solvents applied to unprotected nucleosides and nucleotides

Nucleoside analogues have attracted much attention due to their potential biological activities. Amongst all synthetic nucleosides, C5-modified pyrimidines and C2- or C8-modified purines have been particularly studied. A large variety of palladium cross-coupling reactions, with a majority of them based on the Suzuki–Miyaura reaction, have been developed for preparing the desired nucleoside derivatives. Our objective is to focus this review on the Suzuki–Miyaura cross-coupling of nucleosides using methodologies compatible with green chemistry and sustainable development for one part and bioorthogonality for the other part, which means using aqueous medium and no protection/deprotection steps.

A new route to cyclen, cyclam and homocyclen

Abstract Cyclen, cyclam and homocyclen have been synthesized from the corresponding butanedione-protected linear tetramines. The cyclization step is followed by a facile deprotection of the rigidifying moiety.

Improved microwave-assisted ligand-free Suzuki–Miyaura cross-coupling of 5-iodo-2′-deoxyuridine in pure water

A facile and efficient methodology for direct synthesis of 5-aryl-2′-deoxyuridines was developed through ligand-free Suzuki–Miyaura cross-coupling reactions starting from totally deprotected 5-iodo-2′-deoxyuridine and various boronic acids. Reactions were performed, in pure water, in the presence of very low loading of palladium either by classical thermal heating or with the assistance of microwave irradiation yielding 5-arylated uridine derivatives in moderate to good yields within short reaction times.

Condensation of glyoxal with triethylenetetraamine. Stereochemistry, cyclization and deprotection

Abstract A mixture of bis-aminal isomers was obtained from aqueous glyoxal-triethylenetetraamine condensation. The irreversible isomerization of the species was observed and a new synthesis of cyclen proposed.

First ligand-free, microwave-assisted, Heck cross-coupling reaction in pure water on a nucleoside – application to the synthesis of antiviral BVDU

For the first time, a palladium catalyzed Heck cross-coupling reaction between 5-iodo-2′-deoxyuridine and various acrylate derivatives was performed using ligand-free conditions and microwave assistance in pure water. Those new conditions allowed a totally aqueous access to antiviral BVDU in higher yield than that reported (56 vs. 31% for three steps).

Original access to 5-aryluracils from 5-iodo-2′-deoxyuridine via a microwave assisted Suzuki-Miyaura cross-coupling/deglycosylation sequence in pure water

A facile and efficient methodology to obtain various 5-aryluracil derivatives was developed through a two steps sequence: a ligand-free Suzuki-Miyaura cross-coupling reaction starting from totally deprotected 5-iodo-(2′-deoxy)uridine followed by a very simple deglycosylation procedure in pure water with assistance of microwave irradiation.

Condensation of Glyoxal with Triethylenetetraamine; Isomerization and Cyclization

The condensation of triethylenetetraamine with glyoxal leads to the formation of four stereoisomers A, B, C, D. A is the thermodynamic product and D the kinetic one. These four compounds exhibit equilibrium and isomerization phenomena which are the key-feature of this cyclen synthesis.

Modes of complexation of bis-aminals of linear tetraamines with Group 6 metal carbonyls

Abstract On reaction with Group 6 metal carbonyls M(CO)6, vic type bis-aminals L, issued from the condensation of an α-dicarbonyl compound on a linear tetraamine, give rise to mononuclear cis-M(CO)4L complexes.

Aqueous microwave-assisted cross-coupling reactions applied to unprotected nucleosides.

Metal catalyzed cross-coupling reactions have been the preferred tools to access to modified nucleosides (on the C5-position of pyrimidines and on the C7- or C8-positions of purines). Our objective is to focus this mini-review on the Suzuki-Miyaura and on the Heck cross-couplings of nucleosides using microwave irradiations which is an alternative technology compatible with green chemistry and sustainable development