N′‐tetramethylethylenediamine) or InCl3 (0.33 equiv) with [Li(tmp)] (tmp=2,2,6,6‐tetramethylpiperidino; 1.5 or 1.3 equiv, respectively) were compared with the previously described mixture of ZnCl2⋅TMEDA (0.5 equiv) and [Li(tmp)] (1.5 equiv) for their ability to deprotonate anisole, benzothiazole, and pyrimidine. [(tmp)3CdLi] proved to be the best base when used in tetrahydrofuran at room temperature, as demonstrated
benzothiazole, benzo[b]thiophene, benzo[b]furan, N-Boc-protected indole and pyrrole, and N-phenylpyrazole using an in situ mixture of ZnCl2·TMEDA (0.5 equiv) and lithium 2,2,6,6-tetramethylpiperidide (1.5 equiv) in THF at room temperature is described. The reaction was evidenced by trapping with iodine, regioselectively giving the expected functionalized derivatives in 52−73% yields. A mixture of mono- and disubstituted
苯并恶唑,苯并噻唑,苯并[脱质子b ]噻吩,苯并[ b ]呋喃,Ñ -Boc保护的吲哚和吡咯和Ñ -phenylpyrazole在氯化锌的混合物原位使用2 ·TMEDA(0.5当量)和2,2-锂描述了室温下在THF中的1,6,6-四甲基哌啶(1.5当量)。通过捕获碘,区域选择性地以52-73%的收率选择性地提供了预期的官能化衍生物,证明了该反应。从噻唑开始获得单取代和二取代的衍生物的混合物。2-金属化苯并[ b ]噻吩与苯并[ b ]的交叉偶联反应在钯催化下,用杂芳族氯化物制备呋喃是可行的。考虑到对基本混合物进行的NMR和DFT研究,提出了一种溶液中存在的酰胺化锂和二酰胺化锌协同作用的反应途径。
<i>t</i>-BuONa-mediated direct C–H halogenation of electron-deficient (hetero)arenes
作者:Xia Liu、Xin Zhao、Fushun Liang、Baoyi Ren
DOI:10.1039/c7ob03081a
日期:——
An efficient halogenation of electron-deficient (hetero)arenes is described. The reaction utilizes common t-BuONa as a catalyst (for iodination) or a promoter (for bromination and chlorination), and perfluorobutyl iodide, CBr4 or CCl4 as the readily-available halogenating agents, respectively. The protocol features broad scope, high efficiency, mild conditions and gramscalability. An ionic pathway
Synthesis of Stannylthiazoles and Mixed Stannylsilylthiazoles and their Use for a Convenient Preparation of Mono- and Bis-halothiazoles
作者:A. Dondoni、A. R. Mastellari、A. Medici、E. Negrini、P. Pedrini
DOI:10.1055/s-1986-31766
日期:——
Stannylthiazoles and stannyl-silylthiazoles have been prepared and employed as thiazolyl carbanion equivalents in reactions with halogens to give mono- and mixed bis-halothiazoles in good yields.