Validation of the copper(i)-catalyzed azide-alkyne coupling in ionic liquids. Synthesis of a triazole-linked C-disaccharide as a case study.
The first study of a copper(I)-catalyzed azide-alkyne click reaction in ionic liquids (ILs) is reported. The cycloaddition of a sugar azide with a sugar acetylene (CuI, i-Pr2EtN, 80 degrees C) was carried out in 10 ILs as well as in standard molecular solvents (toluene and DMF) to give the 1,4-disubstituted triazole-linked C-disaccharide. The highest yields (84 and 95%) were registered in Ammoeng 110 and [C(8)dabco][N(CN)(2)]. The latter solvent was recycled in four subsequent reactions without loss of the reaction efficiency. Reactions carried out in the absence of the Hünig's base afforded mixtures of 1,4- and 1,5-disubstituted triazole regioisomers.
Marra
Alberto
A
Dipartimento di Chimica, Laboratorio di Chimica Organica, Università di Ferrara, Via L. Borsari 46, 44100 Ferrara, Italy.
Vecchi
Alessandra
A
Chiappe
Cinzia
C
Melai
Bernardo
B
Dondoni
Alessandro
A
D000480:Alkynes / Q000737:chemistry*; D001386:Azides / Q000737:chemistry*; D002384:Catalysis; D003300:Copper / Q000737:chemistry; D004187:Disaccharides / Q000138:chemical synthesis*; D014230:Triazoles / Q000138:chemical synthesis*
D000480:Alkynes; D001386:Azides; D004187:Disaccharides; D014230:Triazoles; D003300:Copper