Molecular Transformations of Unsaturated Thiacrown Ethers

Unsaturated thiacrown ethers with 15, 18, and 21 members were oxidized to sulfoxides by the reaction
with m-CPBA. The reaction with t-BuOCl at −20 °C also afforded sulfoxides, whereas the reaction at
room temperature yielded cis−trans isomerized compounds. The cis−trans isomerized compound was
also obtained by the photochemical reaction or by the reaction with NCS and NCP. Meanwhile, the
reaction with NBS and NBP provided an acetal via 1,2-bridged bromonium intermediate.

将15元、18元及21元环的不饱和硫杂冠醚（unsaturated thiacrown ethers）与间氯过氧苯甲酸（m-CPBA）反应，可被氧化为亚砜。在-20 ℃下与叔丁基次氯酸（t-BuOCl）反应同样得到亚砜，而在室温下反应则生成顺反异构化产物。该顺反异构化产物亦可通过光化学反应，或与N-氯代琥珀酰亚胺（NCS）、N-氯代邻苯二甲酰亚胺（NCP）反应得到。而与N-溴代琥珀酰亚胺（NBS）、N-溴代邻苯二甲酰亚胺（NBP）反应则经由1,2-桥溴鎓中间体生成缩醛。