Dissecting Competitive Mechanisms: Thionation vs. Cycloaddition in the Reaction of Thioisomünchnones with Isothiocyanates under Microwave Irradiation
作者:David Cantillo、Martín Ávalos、Reyes Babiano、Pedro Cintas、José L. Jiménez、Mark E. Light、Juan C. Palacios
DOI:10.1021/jo900960a
日期:2009.10.16
competition between thionation and 1,3-dipolar cycloaddition takes place. The process is synthetically disappointing at room temperature requiring prolonged reaction times for completion. The protocol has been subsequently investigated by using both microwave dielectric heating and conventional thermal heating (oil bath) in DMF at 100 °C with an accurate internal reaction temperature measurement. Although a slight
本文详细记录了1,3-噻唑-4-油酸酯(thioisomünchnones)与异硫氰酸芳基酯的反应。与手性模型已经表明,在这些条件下发生硫化,以提供1,3-噻唑-4-硫醇盐,并且这个过程实际上是一个逐步的多米诺反应(有机化学杂志。2009年,74(3698−3705),我们将这项研究扩展到单环硫代异氰酸酯。在此,发生硫代化和1,3-偶极环加成之间的竞争。该方法在室温下令人失望,需要更长的反应时间才能完成反应。随后通过在100°C的DMF中同时使用微波介电加热和常规热加热(油浴)对协议进行了研究,并进行了精确的内部反应温度测量。尽管在微波辐射下观察到反应略有加速,但在大多数情况下,观察到的产率和化学选择性非常相似。因此,可以得出这样的结论:在实验错误的范围内,反应性与非热效应无关,这与最近对该主题的重新评估相一致,尤其是Kappe及其同事(J.Org。化学 2008年,73,36; J.Org。化学