Chiral aminoalcohol promoted one-pot addition of zinc alkynylides to α-keto esters and kinetic resolution of the resulting tertiary propargylic alcohols was developed. The reaction provided us an alternative approach to access optically activetertiary α-hydroxy-β-ynyl esters with enantiomeric excesses up to 98%.
A novel class of chiral N-sulfonyl oxaziridines is introduced for use as structurally modifiable chiral oxidants. These oxaziridines are readily prepared from N-sulfonyl α-imino esters in a highly enantioenriched form by oxidation with hydrogen peroxide using L-isoleucine-derived triaminoiminophosphorane as a catalyst. The distinct advantage of their structural modularity is demonstrated through the
Stable α-alkynylacetic acid derivatives related to cis-enediyne were synthesized and the rate of decarboxylative cycloaromatization of 3,5-difluoro derivative 7c was found to be much faster than that of the corresponding phenyl derivative 7a. The cycloaromatization reaction mechanisms of 7c under various conditions were investigated.
Aryl Halides as Halogenation Reagents in the Bromination and Iodination of Arene-Tethered Diols
作者:Fucheng Yin、Yifan Chen、Zhongwen Luo、Shang Li、Lingyi Kong、Xiaobing Wang
DOI:10.1021/acs.orglett.2c02358
日期:2022.9.16
class of building blocks that are commonly used in organicsynthesis. In this study, we demonstrate usage of aryl bromides and aryl iodides in C–Br or C–I bond formation. Methyl 2-bromobenzoate and 2-nitrophenyl iodides were developed as mild and effective bromination and iodination reagents for functionalization of arene-tethered diols. This efficient cascaded catalysis can be applied to the total syntheses
芳族卤化物构成了有机合成中常用的一类有价值的结构单元。在这项研究中,我们展示了芳基溴化物和芳基碘化物在 C-Br 或 C-I 键形成中的使用。开发了 2-溴苯甲酸甲酯和 2-硝基苯基碘化物作为温和有效的溴化和碘化试剂,用于芳烃束缚二醇的官能化。这种高效的级联催化可应用于天然产物 Mafaicheenamine A 和 Claulamine A 的全合成。
First Iridium-Catalyzed Highly Enantioselective Hydrogenation of β-Nitroacrylates
The first highly chemo- and enantioselective hydrogenation of beta-nitroacrylates was accomplished with an iridium catalyst (Ir-4) with yields and enantioselectivities of up to 96% and 98% ee, respectively. The resulting alpha chiral beta-nitro propionates are attractive building blocks for the synthesis of chiral beta(2)-amino acids, which are the core scaffolds of bioactive natural products, pharmaceuticals, and beta-peptides.