1,3-Dithiolanes from Cycloadditions of Alicyclic and Aliphatic Thiocarbonyl Ylides with Thiones: Regioselectivity
作者:Rolf Huisgen、Grzegorz Mloston、Kurt Polborn、Reiner Sustmann
DOI:10.1002/chem.200204659
日期:2003.5.23
The regiochemistry of 1,3-dithiolanes obtained from thiocarbonyl ylides 9 and thiones 10 shows a striking dependence on substituents. Previously and newly performed experiments indicate that sterically hindered cycloalkanethione S-methylides and dialkylthioketone S-methylides react with alicyclic and aliphatic thiones to give the 2,2,4,4-tetrasubstituted 1,3-dithiolanes 11 exclusively. Aryl groups
由硫代羰基酰基化物9和硫酮10获得的1,3-二硫杂环戊烷的区域化学显示出对取代基的显着依赖性。先前和新近进行的实验表明,空间位阻的环烷硫酮S-甲基化物和二烷基硫酮S-甲基化物与脂环族和脂族硫酮反应,仅得到2,2,4,4-四取代的1,3-二硫杂环戊烷11。一种或两种反应物中的芳基导致偏向于甚至完全形成4,4,5,5-四取代的1,3-二硫杂环戊烷12。似乎涉及几种机理,但缺乏实验标准,令人不安。硫代丙酮S-甲基化物与硫代丙酮之间环加成的量子化学计算(参见前文)为协同过程提供了比经由C,S-或C的两步途径更低的活化能,C-双基; 2,4-取代的1,3-二硫杂环戊烷相对于4,5-取代的类型的青睐预期随着取代基的增加而增加。芳基稳定中间双基。讨论了区分区域异构二硫杂环戊烷的实验标准。通过在重氮甲烷和硫酮之间进行1,3-环加成并随后从通常可分离的2,5-二氢-1,3,4-噻二唑17中除去N(2),制得