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Abstract：
Cycloaddition reactions play a pivotal role in synthetic chemistry for the direct assembly of cyclic architectures. However, hurdles remain for extending the C4 synthon to construct diverse heterocycles via programmable [4+n]-cycloaddition. Here we report an atom-economic and modular intermolecular cycloaddition using furan-fused cyclobutanones (FCBs) as a versatile C4 synthon. In contrast to the well-documented cycloaddition of benzocyclobutenones, this is a complementary version using FCB as a C4 reagent. It involves a C-C bond activation and cycloaddition sequence, including a Rh-catalyzed enantioselective [4 + 2]-cycloaddition with imines and an Au-catalyzed diastereoselective [4 + 4]-cycloaddition with anthranils. The obtained furan-fused lactams, which are pivotal motifs that present in many natural products, bioactive molecules, and materials, are inaccessible or difficult to prepare by other methods. Preliminary antitumor activity study indicates that 6e and 6 f exhibit high anticancer potency against colon cancer cells (HCT-116, IC50 = 0.50 ± 0.05 μM) and esophageal squamous cell carcinoma cells (KYSE-520, IC50 = 0.89 ± 0.13 μM), respectively.
摘要：
环加成反应在直接组装环结构的合成化学中起着关键作用。然而,通过可编程的[4n]环加成延伸C4合成子构建不同的杂环仍然存在障碍。在这里，我们报告了使用呋喃稠合的环丁酮（FCB）作为通用C4合成子的原子经济和模块化分子间环加成。与文献记载的苯并环丁烯酮的环加成相反，这是使用FCB作为C4试剂的补充版本。它涉及C-C键活化和环加成序列，包括Rh催化的与亚胺的对映选择性[42]-环加成和Au催化的与蒽醌的非对映选择性[44]-环加成。获得的呋喃稠合内酰胺，这是许多天然产品中存在的关键图案，生物活性分子，和材料,用其他方法难以接近或难以准备。初步抗肿瘤活性研究表明，6e和6f对结肠癌细胞（HCT-116，IC50=0.50±0.05μM）和食管鳞状细胞癌细胞（KYSE-520，IC50=0.89±0.13μM）具有较高的抗癌效力，分别。
