Two Novel 1,2,4,5-Tetrazines that Participate in Inverse Electron Demand Diels−Alder Reactions with an Unexpected Regioselectivity
作者:Akiyuki Hamasaki、Richard Ducray、Dale L. Boger
DOI:10.1021/jo051832o
日期:2006.1.1
of their corresponding sulfides (2 and 3), being derived from their enhanced electron-deficient character and resulting in a wider range of potential dienophile choices or the use of milder reaction conditions. The cycloaddition reactions were expectedly regioselective, typically producing a single cycloadduct, ensuring their synthetic utility, but both were found to proceed with a regioselectivity opposite
两个新的不对称1,2,4,5-四嗪,3-甲基亚磺酰基-6-甲硫基-1,2,4,5-四嗪(4)和3-(苄氧基羰基)氨基-6-甲基亚磺酰基-1,2,4制备了5,5-四嗪(5),并定义了它们参与分子间逆电子需求Diels-Alder反应的范围。如预期的那样,亚砜4和5(4 > 5)的反应活性大大高于其相应的硫化物(2和3)。),是由于它们增强的电子缺陷特性而导致的,从而导致了更大范围的潜在亲双烯体选择或使用了较温和的反应条件。预期环加成反应是区域选择性的,通常产生单个环加合物,确保其合成效用,但是发现两者都以与预期相反的区域选择性进行,并与2和3所观察到的互补。