A series of trans- and cis-2,3-di R)oxy-1,4-dIoxanes (R = Me,Ph, Ac) and some 2,5-disubstituted analogis were prepared and analysed by various NMR techniques. The trans isomers occur in more than 96% as diaxial conformers. Molecular mechanics calculations largely confirm these findings, which are interpreted -in terms of combined anomeric and gauche effects.
制备了一系列反式和顺式-2,3-二R)氧基-1,4-
二恶烷(R = Me,Ph,Ac)和一些2,5-二取代的类似物,并通过各种NMR技术进行了分析。反式异构体以双轴构象异构体的形式存在于96%以上。分子力学计算在很大程度上证实了这些发现,这些发现是根据端基异构和网状效应的组合来解释的。