Abstract:
Although dearomative functionalizations enable the direct conversion of flat aromatics into precious three-dimensional architectures, the case for simple arenes remains largely underdeveloped owing to the high aromatic stabilization energy. We herein report a dearomative sequential addition of two nucleophiles to arene π-bonds through umpolung of chromium-arene complexes. This mode enables divergent dearomative carbonylation reactions of benzene derivatives by tolerating various nucleophiles in combination with alcohols or amines under CO-gas-free conditions, thus providing modular access to functionalized esters or amides. The tunable synthesis of 1,3- or 1,4-cyclohexadienes as well as the construction of carbon quaternary centers further highlight the versatility of this dearomatization. Diverse late-stage modifications and derivatizations towards synthetically challenging and bioactive molecules reveal the synthetic utility. A possible mechanism was proposed based on control experiments and intermediate tracking.
摘要:
尽管脱芳烃官能化能够将扁平芳烃直接转化为珍贵的三维结构,由于高芳烃稳定能,简单芳烃的情况在很大程度上仍然不发达。我们在此报告了两种亲核试剂通过铬-芳烃配合物的去芳香化顺序添加到芳烃π键。该模式通过在无CO气体条件下耐受各种亲核试剂与醇或胺的组合,可以实现苯衍生物的发散脱芳羰基化。因此提供了对功能化酯或酰胺的模块化访问。1,3-或1,4-环己二烯的可调合成以及全碳季中心的构建进一步突出了这种脱芳构化的多功能性。对合成挑战性和生物活性分子的各种后期修饰和衍生化揭示了合成效用。基于控制实验和中间跟踪,提出了一种可能的机制。