We report the conversion of 2,3‐dihydrobenzo[b][1,4]dioxine‐2‐carboxamides, (derived from 2,3‐dihydrobenzo[b][1,4]dioxine‐2‐carboxylic acid and 2‐haloanilines) to 3‐oxoquinolin‐2(1H)‐one motifs using catalytic amounts of Pd(OAc)₂, PPh_3, BINOL and Cs₂CO₃ (1.5 equiv). This conversion occurred via the less common formal 6‐endo‐trig cyclization and chelation‐controlled β‐arylation (Heck‐type reaction) pathways. Initially, a base‐mediated ring‐opening of the 2,3‐dihydrobenzo[b][1,4]dioxine moiety generates an acrylamide intermediate in situ, which then undergoes a formal 6‐endo‐trig cyclization‐involved Heck‐type reaction to afford 3‐oxoquinolin‐2(1H)‐one motif. The proposed acrylamide intermediate was isolated, characterized by the X‐ray structure analysis and then, it was also treated under the experimental conditions, which afforded the expected 3‐oxoquinolin‐2(1H)‐one; thus, providing a strong support for the proposed mechanism. Various 3‐oxoquinolin‐2(1H)‐one motifs were synthesized in moderate to good yields. Representative 3‐oxoquinolin‐2(1H)‐one motifs were characterized by X‐ray analysis.

中文翻译：

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通过开环和正式的6-内-trig-环化涉及的Heck反应将2,3-二氢苯并[b] [1,4]二恶英-2-羧酰胺转化为3-氧喹啉-2（1H）-一

我们报道了2,3-二氢苯并[ b ] [1,4]二恶英-2-羧酰胺的转化（（衍生自2,3-二氢苯并[ b ] [1,4]二恶英-2-羧酸和2-卤代苯胺） ）催化量的Pd（OAc）₂，PPh _3， BINOL和Cs ₂ CO ₃（1.5当量）合成3-氧代喹啉-2（1 H）-基序。这种转化是通过不太普遍的形式化的6-内-trig环化和螯合控制的β-芳基化（Heck型反应）途径发生的。最初，2,3-二氢苯并[ b ] [1,4]二恶英部分的碱介导的开环反应原位生成丙烯酰胺中间体，然后进行正式的6-内-trig环化涉及Heck型反应，得到3-氧代喹啉-2（1 H）-one基序。分离出所提出的丙烯酰胺中间体，通过X射线结构分析对其特征进行表征，然后在实验条件下进行处理，从而获得了预期的3-氧代喹啉-2（1 H）-酮；因此，为建议的机制提供了有力的支持。合成了各种3-氧代喹啉-2（1 H）-基序，产量中等至良好。代表性的3-氧代喹啉-2（1H）-1基序通过X射线分析表征。