Jiang Shimin, Liang Meng, Bai Jiang, Yang Ruchun, Chen Xi, Huang Haiyang, Ding Hai-Xin, Luo Mu-Jia, Song Xian-Rong, Xiao Qiang
Institute of Organic Chemistry, Jiangxi Science & Technology Normal University, Key Laboratory of Organic Chemistry, Nanchang, Jiangxi 330013, China.
J Org Chem. 2024 May 3;89(9):6416-6427. doi: 10.1021/acs.joc.4c00443. Epub 2024 Apr 14.
A novel conversion of 1,5-diynols into sulfonylated benzo[]fluorenes is reported by a TFA-promoted cascade cyclization with sodium sulfinates under mild conditions. This strategy provides an efficient and practical approach for accessing various sulfonated benzo[]fluorenes in moderate to excellent yields under metal-free conditions. On the basis of the control experimental results and density functional theory calculations, a possible cascade transformation mechanism consisting of the dehydration of propargylic alcohols, sulfonylation, allenylation, and Schmittel-type cyclization is proposed. It is worth noting that TFA played an important role in this cascade cyclization, which promoted C-SOR bond cleavage in a propargylic sulfone intermediate to form allenyl sulfones, followed by Schmittel-type cyclization to give the target product.
据报道，在温和条件下，通过三氟乙酸（TFA）促进的与亚磺酸钠的串联环化反应，可实现1,5 - 二炔醇向磺酰化苯并[]芴的新型转化。该策略为在无金属条件下以中等至优异产率获得各种磺酰化苯并[]芴提供了一种高效且实用的方法。基于对照实验结果和密度泛函理论计算，提出了一种可能的串联转化机制，该机制包括炔丙醇的脱水、磺酰化、烯丙基化和施密特尔型环化。值得注意的是，TFA在该串联环化反应中起重要作用，它促进炔丙基砜中间体中的C - SOR键断裂以形成烯丙基砜，随后通过施密特尔型环化得到目标产物。
