A facile metal-free synthesis of multi-substituted pyrimidines from readily available amidines and α,β-unsaturated ketones is reported. The synthesis involved a [3 + 3] annulation to form a dihydropyrimidine intermediate, which was converted to pyrimidine through visible-light-enabled photo-oxidation rather than the usual transition-metal-catalyzed dehydrogenation. The mechanism of the photo-oxidation
报道了一种从易得的脒和 α,β-不饱和酮中简便地无
金属合成多取代
嘧啶的方法。合成涉及 [3 + 3] 环化形成二氢
嘧啶中间体,通过可见光光氧化而不是通常的过渡
金属催化脱氢将其转化为
嘧啶。研究了光氧化的机理。这项工作为
嘧啶提供了一种替代方法,具有易于操作、温和和绿色条件以及广泛底物的优点,避免了对过渡
金属催化剂和强碱的依赖。