Ansari Monish Arbaz, Yadav Dhananjay, Singh Maya Shankar
Department of Chemistry, Institute of Science, Banaras Hindu University, Varanasi, 221005, India.
Chemistry. 2020 Jun 26;26(36):8083-8089. doi: 10.1002/chem.202000279. Epub 2020 Jun 8.
A photocatalyst- and additive-free, visible-light-mediated chemoselective domino protocol was devised to access fully substituted thiazoline derivatives from β-ketothioamides and α-diazo 1,3-diketones at moderate temperature in open air. The reaction proceeds through in situ generation of electrophilic carbenes from α-diazo 1,3-diketones by a low-energy blue LED (448 nm), which undergoes selective coupling with nucleophilic β-ketothioamides to give thiazolines by successive formation of C-S and C-N bonds in one stretch. Notably, the benign and clean conditions, operational simplicity, sustainability, 100 % carbon economy, high yields, and wide functional-group tolerance are further attributes of the strategy. A mechanistic rationale for this cascade reaction sequence is well supported by control experiments.
设计了一种无光催化剂和添加剂、可见光介导的化学选择性多米诺反应方案，用于在开放空气中的中等温度下从β-酮硫代酰胺和α-重氮1,3-二酮制备完全取代的噻唑啉衍生物。该反应通过低能量蓝色发光二极管（448 nm）从α-重氮1,3-二酮原位生成亲电卡宾进行，亲电卡宾与亲核β-酮硫代酰胺进行选择性偶联，通过连续形成C-S键和C-N键一步得到噻唑啉。值得注意的是，该策略还具有温和清洁的条件、操作简单、可持续性、100%的碳经济性、高产率以及广泛的官能团耐受性等优点。对照实验很好地支持了这种级联反应序列的机理原理。
