Ring Contraction of 3,6-Dihydro-2H-thiopyrans to Thiolanes by an Iodo-Oxyacylation Reaction
作者:Andre C. B. Lucassen、Binne Zwanenburg
DOI:10.1002/ejoc.200300166
日期:2004.1
poly-functionalised thiolanes in good yield. The formation of these thiolanes is believed to proceed through either a nucleophilic or an electrophilic pathway leading to 4,5-cis-substituted derivatives. The use of unsymmetrical 2,2-substituted 3,6-dihydro-2H-thiopyrans gave mixtures of isomers that could be separated in several cases. From a 3-substituted thiopyran a 2,2,3,4,5-pentasubstituted thiolane was obtained
在羧酸存在下,官能化的 3,6-二氢-2H-噻喃与 N-碘代琥珀酰亚胺的反应导致立体定向形成多官能化硫戊环,收率良好。这些硫杂环戊烷的形成被认为是通过亲核或亲电途径进行的,从而产生 4,5-顺式取代的衍生物。使用不对称的 2,2-取代的 3,6-二氢-2H-噻喃产生异构体的混合物,可以在几种情况下分离。从3-取代的噻喃得到2,2,3,4,5-五取代的噻吩。尝试使用醇作为外部亲核试剂的 NIS、NBS 和 N-溴乙酰胺均未成功。与原位生成的 IN3 的碘叠氮反应也不成功。((C) Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)。