K<sub>3</sub>PO<sub>4</sub>-KOH Mixture as Efficient Reagent for the Deprotection of 4-Aryl-2-methyl-3-butyn-2-ols to Terminal Acetylenes
作者:Alexey Smeyanov、Andreas Schmidt
DOI:10.1080/00397911.2012.744841
日期:2013.10.18
Abstract A mixture of potassium hydroxide and potassium phosphate was found to be an active reagent mixture for the cleavage of 2-hydroxypropyl-protected acetylenes. The reaction was performed in toluene at reflux temperature and gave terminal acetylenes in good to excellent yields within very short periods of time. Numerous other functional groups are tolerated. Supplementary materials are available
We have developed highly enantioselective synthesis of functionalized helically chiral molecules via a Rh-catalyzed [2 + 2 + 2] cycloaddition and synthesis of ladder-type molecules via an unprecedented Rh-catalyzed formal [2 + 1 + 2 + 1] cycloaddition involving C−C triple bond cleavage.
Organocatalytic Enantioselective Construction of Axially Chiral Sulfone-Containing Styrenes
作者:Shiqi Jia、Zhili Chen、Nan Zhang、Yu Tan、Yidong Liu、Jun Deng、Hailong Yan
DOI:10.1021/jacs.8b03211
日期:2018.6.13
describe herein an organocatalytic enantioselective approach for the construction of axially chiral sulfone-containing styrenes. Various axially chiral sulfone-containing styrene compounds were prepared with excellent enantioselectivities (up to >99% ee) and almost complete E/ Z selectivities (>99% E/ Z). Furthermore, the axially chiral sulfone-containing styrenes could be easily converted into phosphonic
diastereomeric atropisomers in good yield and nearly 1:1 ratios. Facile chromatographic separation of the naphthyl tetrahydroisoquinolines gave access to both pure and stable diastereomeric atropisomers. The deprotection and direct functionalization of the methyl- or methoxymethyl-protected 2-naphthyl position of the atropisomers were investigated. The configuration of the formed atropisomers was assigned
在热和光化学条件下,通过 CoI-烯烃配合物催化的关键 [2+2+2] 环加成反应步骤,新型、手性、脯氨酸基萘二炔与不同腈的反应以良好的收率和接近 1:1 的比例得到非对映异构阻转异构体比率。萘基四氢异喹啉的简便色谱分离提供了纯的和稳定的非对映阻转异构体。研究了阻转异构体的甲基或甲氧基甲基保护的 2-萘基位置的脱保护和直接官能化。根据 X 射线研究和圆二色光谱的结果确定形成的阻转异构体的构型。
One-Step Construction of Five Successive Rings by Rhodium-Catalyzed Intermolecular Double [2+2+2] Cycloaddition: Enantioenriched [9]Helicene-Like Molecules
Enantioenriched fluorenone‐containing [9]helicene‐likemolecules have been successfully synthesized through the formation of five successive rings by rhodium‐catalyzed intermolecular double [2+2+2] cycloadditions of 2‐naphthol‐linked tetraynes with dialkynylketones (see scheme; cod=cycloocta‐1,5‐diene). Their unique crystal structures and photophysical properties have also been determined.