A facile approach to 2,2′-bipyridine based thiacrown ethers and their sulfoxides by DA-rDA reaction of 5,5′-bi-1,2,4-triazine thiamacrocycles. The conformation studies
作者:Justyna Ławecka、Zbigniew Karczmarzyk、Ewa Olender、Ewa Wolińska、Danuta Branowska、Andrzej Rykowski
DOI:10.3998/ark.5550190.0012.911
日期:——
Diels-Alder/retro Diels-Alder (DA-rDA) reactions of 5,5′-bi-1,2,4-triazine thiamacrocycles 4a–c afforded medium-size 2,2′-bipyridine based thiacrown ethers 5a–c in good yield. The latter were oxidized to non-racemic monosulfoxides 7a–c using Davis oxaziridine and tested as chiral auxilaries in the asymmetric addition of diethyl zinc to benzaldehyde. The theoretical calculations at DFT /B3LYP/6-311G**
Diels-Alder/retro Diels-Alder (DA-rDA) 反应 5,5'-bi-1,2,4-三嗪硫大环 4a-c 得到中等大小的基于 2,2'-联吡啶的噻冠醚 5a-c良好的产量。后者使用 Davis oxaziridine 被氧化为非外消旋单亚砜 7a-c,并在二乙基锌与苯甲醛的不对称加成中作为手性助剂进行测试。进行了 DFT /B3LYP/6-311G** 水平的理论计算,从而建立了目标硫大环的顺式或反式构象偏好。