| Popis: |
The photodeoxygenation of sugar esters of aliphatic acids in hexamethylphosphoric triamide (HMPT) and mixtures thereof with water, is initiated by photoionization of HMPT. The solvated electron thus formed, reduces the ester to its radical anion, which is an intermediate for both the formation of the deoxy sugar and the reproduction of the corresponding alcohol. A separation of the carboxylate anion leads to a radical of the deoxy sugar which reacts further via hydrogen transfer from HMPT, the acid residue, or from other sugar molecules. The incorporation of the hydrogen atom occurs, in all cases, preferentially at the sterically less hindered side. |
