Novel Methods for the Facile Construction of 3,3-Disubstituted and 3,3-Spiro-2<i>H</i>,4<i>H</i>-benzo[<i>e</i>]1,2-thiazine-1,1-diones: Synthesis of (11<i>S</i>,12<i>R</i>,14<i>R</i>)-2-Fluoro-14-methyl-11-(methylethyl)spiro[4<i>H</i>-benzo[<i>e</i>]- 1,2-thiazine-3,2‘-cyclohexane]-1,1-dione, an Agent for the Electrophilic Asymmetric Fluorination of Aryl Ketone Enolates
作者:Zhaopeng Liu、Norio Shibata、Yoshio Takeuchi
DOI:10.1021/jo0055584
日期:2000.11.1
sultams 8a-h in high yields. The chiral spiro sultams 8g, h were subjected to FClO(3) fluorination to give the N-fluorosultams 11a,b, respectively, which were tested for electrophilic asymmetric fluorination of aryl ketone enolates. As a result, the N-fluorosultam 11a exhibited modest asymmetric inducing abilities with the highest ee, reaching 70% for enantioselective fluorination of the lithium enolate
描述了用于3,3-二取代和3,3-螺2H,4H-苯并[e] [1,2]噻嗪-1,1-二酮8a-h的简便构建的新方法。N-Boc-邻甲苯磺酰胺6的邻甲基锂化反应,然后与多种酮反应,得到相应的甲醇磺酰胺7a-g,将其在酸性(甲磺酸)或中性(NaI / TMSCl / MeCN)条件下环化为可以高产地提供8a-h的苏丹娜。将手性螺合磺酰胺8g,h进行FC10(3)氟化处理,分别得到N-氟磺酰胺11a,b,将其测试为芳基酮烯醇酸酯的亲电不对称氟化。结果,N-氟磺酰胺11a表现出中等的不对称诱导能力,具有最高的ee,对于2-甲基-1-四氢萘酮的烯醇锂的对映选择性氟化达到70%。