Merging Electrochemical Synthesis and Post-Ugi Cyclization for the Synthesis of Diverse 4‑Imidazolidinones

Despite the appreciation for electro-organic synthesis, postmulticomponent reaction transformation chemistry rarely exploits this powerful technology. Herein, we explore post-Ugi cyclization reactions using N-centered radical-mediated intramolecular ipso cyclization to synthesize diverse spirocyclic variants of 4-imidazolidinones through the use of electrochemically generated amidyl radicals from the bis-amides of the Ugi adducts. This protocol features an undivided cell setup under constant-current conditions with carbon–platinum electrodes. These metal- and reagent-free reactions are scalable and have broad substrate scope.尽管有机电合成（electro-organic synthesis）已得到广泛认可，但多组分反应后转化化学领域却极少应用这一高效技术。本文中，我们以乌吉加合物（Ugi adducts）的双酰胺为底物，通过电化学原位生成的酰胺自由基（amidyl radicals），开展了乌吉反应后环化反应的研究：借助氮中心自由基（N-centered radical）介导的分子内本位环化，合成了结构多样的4-咪唑啉酮（4-imidazolidinones）螺环衍生物。该反应体系采用无分隔电解池装置，在恒流条件下以碳-铂电极（carbon–platinum electrodes）作为工作电极。此类无需金属催化剂与外加试剂的反应具有优异的可规模化性，且底物适用范围广泛。