Acyl Group Migration in Pyranosides as Studied by Experimental and Computational Methods |
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| Authors: | Robert Lassfolk Manuel Pedrón Prof Tomás Tejero Prof Pedro Merino Johan Wärnå Prof Reko Leino |
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| Institution: | 1. Laboratory of Molecular Science and Engineering, Åbo Akademi University, 20500 Turku, Finland;2. Institute of Biocomputation & Physics of Complex Systems (BIFI), University of Zaragoza, 50009 Zaragoza, Spain;3. Institute of Chemical Synthesis & Homogeneous Catalysis (ISQCH), University of Zaragoza, 50009 Zaragoza, Spain;4. Laboratory of Industrial Chemistry and Reaction Engineering, Åbo Akademi University, 20500 Turku, Finland |
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| Abstract: | Acyl group migration affects the synthesis, isolation, manipulation and purification of all acylated organic compounds containing free hydroxyl groups, in particular carbohydrates. While several isolated studies on the migration phenomenon in different buffers have been reported, comprehensive insights into the overall migration process in different monosaccharides under similar conditions have been lacking. Here, we have studied the acyl migration in different monosaccharides using five different acyl groups by a combination of experimental, kinetic and theoretical tools. The results show that the anomeric configuration in the monosaccharide has a major influence on the migration rate, together with the relative configurations of the other hydroxyl groups and the nature of the migrating acyl group. Full mechanistic model, based on computations, demonstrates that the acyl migration proceeds through an anionic stepwise mechanism with linear dependence on the OH−] and the pKa of the hydroxyl group toward which the acyl group is migrating. |
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| Keywords: | acyl group migration carbohydrates computational chemistry NMR spectroscopy reaction mechanism |
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