The DielsâAlder cycloadditions of cyclopentadiene and 2,3-dimethyl-1,3-butadiene to a range of 2-thio-3-chloroacrylamides under thermal, catalytic and microwave conditions is described. The influence of reaction conditions on the outcome of the cycloadditions, in particular the stereoselectivity and reaction efficiency, is discussed. While the cycloadditions have been attempted at the sulfide, sulfoxide and sulfone levels of oxidation, use of the sulfoxide derivatives is clearly beneficial for stereoselective construction of DielsâAlder cycloadducts.
介绍了在热、催化和微波条件下,
环戊二烯和
2,3-二甲基-1,3-丁二烯与一系列 2-
硫代-
3-氯丙烯酰胺的 DielsâAlder 环加成反应。讨论了反应条件对环化反应结果的影响,特别是立体选择性和反应效率。虽然环化反应是在
硫化物、亚砜和砜的氧化
水平上进行的,但使用亚砜衍
生物显然有利于立体选择性地构建 DielsâAlder 环加成物。