A Simple and Efficient Two-Step Synthesis of 1,2,3-Triiodoarenes via Consecutive C–H Iodination/ipso-Iododecarboxylation Strategy: A Potential Application towards ortho-Diiodoarenes by Regioselective Metal–Iodine Exchange Reaction
Base- and Additive-Free Ir-Catalyzed <i>ortho</i>-Iodination of Benzoic Acids: Scope and Mechanistic Investigations
作者:Elis Erbing、Amparo Sanz-Marco、Ana Vázquez-Romero、Jesper Malmberg、Magnus J. Johansson、Enrique Gómez-Bengoa、Belén Martín-Matute
DOI:10.1021/acscatal.7b02987
日期:2018.2.2
A protocol for the C–H activation/iodination of benzoic acids catalyzed by a simple iridium complex has been developed. The method described in this paper allows the ortho-selective iodination of a variety of benzoic acids under extraordinarily mild conditions in the absence of any additive or base in 1,1,1,3,3,3-hexafluoroisopropanol as the solvent. The iridium catalyst used tolerates air and moisture
products from the genus Selaginella with unusual alkynyl phenol skeletons and extensive biological activities. Previous structural simplification of these natural compounds afforded a series of diaryl acetylene derivatives with hypoxia-inducible factor 1 (HIF-1) inhibitory activity. In this study, we synthesized thirty compounds by stepwise optimization using methyl 3-(4-methoxylphenyl ethynyl)-[4′-methoxyl-1
2-(2H-Tetrazol-2-yl)benzoicacid 1 and analogs were prepared via Cu(I) catalyzed C–N coupling of 2-iodo or 2-bromo benzoicacids with 5-(ethylthio)-1H-tetrazole followed by reductive cleavage of the thioether bond. The C–N coupling was regioselective toward the N2-position on tetrazole. The scope of this methodology was demonstrated on a series of 2-halobenzoic acid substrates in moderate yields.
An extremely concise total synthesis of a potent phosphodiesterase-4 inhibitory natural product, selaginpulvilin D, is reported. The synthesis features a one-pot, 3-fold electrophilic aromatic substitution sequence to assemble a 9,9-diarylfluorene core. The approach allows access to useful quantities of a selaginpulvilin natural product for the first time.
Stereoretentive Intramolecular Glycosyl Cross-Coupling: Development, Scope, and Kinetic Isotope Effect Study
作者:Duk Yi、Feng Zhu、Maciej A. Walczak
DOI:10.1021/acs.orglett.8b01927
日期:2018.8.3
A series of cyclic C-glycosides were synthesized using the palladium-catalyzed stereoretentive intramolecular glycosylation of aryl iodides by employing a bulkyphosphine ligand. A variety of functional groups are tolerated in the reaction, and enantioenriched anomeric nucleophiles could be coupled without erosion of optical purity. This study offers a unified method to access both cis- and trans-fused
通过使用庞大的膦配体,使用钯催化的芳基碘的立体保留分子内糖基化合成了一系列环状C-糖苷。反应中允许使用多种官能团,并且对映体富集的异头亲核试剂可以在不损害光学纯度的情况下偶联。这项研究提供了一种通过利用 Stille 反应的立体保持性来访问顺式和反式稠环的统一方法。此外,分子间和分子内交叉偶联的竞争实验显示,二次 KIE 分别为 1.43 和 0.81,表明在过渡态存在截然不同的空间拥塞。