Pentaspiranes and hexaspiranes with 1,3-dioxane or 1,3-oxathiane rings: synthesis and stereochemistry

摘要

The synthesis and stereochemistry of the first reported pentaspiro- and hexaspiro-1,3-dioxane and polyspiro-1,3-oxathiane (from dispiro to hexaspiro) derivatives are described. The crystal structures of a dispiro- and tetraspiro-1,3-oxathiane were determined by X-ray diffraction methods. NMR and chiral column HPLC investigations in solution revealed flexible and semiflexible structures for which syn-anti, cis-trans and d,l isomers were observed. (C) 2004 Elsevier Ltd. All rights reserved. [References: 40]