Coupling of Anhydro-Aldose-Tosylhydrazones with Boronic Acids

PS1 Poster session 1 Odd numbers
Location (hall): 
Start/end time: 
Monday, July 1, 2019 - 15:45 to 17:15

Marietta Tóth1, Zsolt Szentjóbi1, Tímea Kaszás1, Bernadett Balázs1, Balázs Á. Baráth1, Tekla Blága1, Paola Granatino1, László Somsák1

1University of Debrecen, Debrecen, Hungary

In the past decade N-tosylhydrazones emerged as partners in metal-catalyzed and also in metal-free coupling reactions for the formation of carbon-carbon and carbon-heteroatom bonds. One reason for this is that aliphatic and aromatic tosylhydrazones are readily available and stable compounds, and diazo compounds and carbenes, key-intermediates in coupling reactions, can be generated from N-tosylhydrazones in situ [1, 2]. On the contrary, anhydro-aldose tosylhydrazones 1 are not readily available, and their preparation needs special methods. We have elaborated a synthetic method to get such types of compounds by reduction of glycosyl cyanides followed by in situ trapping of the intermediate imine by tosylhydrazine [3, 4]. Based on these preliminaries we have started to examine systematically the coupling reactions of anhydro-aldose tosylhydrazones. It is known from the literature that coupling of N-tosylhydrazones with boronic acids results in C-C bond formation [5, 6]. Our goal was to study some new metal free and metal-catalyzed coupling reactions of ester and ether protected anhydro-aldose tosylhydrazones 1. The metal-free couplings gave the ring-opened heptenitols 2 while metal-catalyzed reactions resulted in substituted exo-glycals 3 (See Figure 1). 

Figure 1.


The research was supported by the EU and co-financed by the European Regional Development Fund under the project GINOP-2.3.2-15-2016-00008, and by the National Research, Development and Innovation Office under the project FK128766.

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