Rhodium-Catalyzed Asymmetric Conjugate Alkynylation/Aldol Cyclization Cascade for the Formation of α-Propargyl-β-hydroxyketones
作者:Ken-Loon Choo、Mark Lautens
DOI:10.1021/acs.orglett.8b00153
日期:2018.3.2
A rhodium-catalyzedconjugatealkynylation/aldol cyclization cascade was developed. Densely functionalized cyclic α-propargyl-β-hydroxyketones were synthesized with simultaneous formation of a C(sp)–C(sp3) bond, a C(sp3)–C(sp3) bond, as well as three new contiguous stereocenters. The transformation was achieved with excellent enantio- and diastereoselectivities using BINAP as the ligand. The synthetic
One-Pot, Three-Step Synthesis of Cyclopropylboronic Acid Pinacol Esters from Synthetically Tractable Propargylic Silyl Ethers
作者:Jonathan A. Spencer、Craig Jamieson、Eric P. A. Talbot
DOI:10.1021/acs.orglett.7b01778
日期:2017.7.21
propargylic silyl ethers can be converted to complex cyclopropylboronic acid pinacol esters in an efficient one-pot procedure. Terminal acetylenes undergo a Schwartz’s reagent catalyzed hydroboration; subsequent addition of further Schwartz’s reagent and Lewis acid-mediated activation of neighboring silyl ether allows cyclization to access a range of cyclopropylboronic acid pinacol esters. The scope includes
Palladium(II)-Catalyzed Site-Selective C(sp<sup>3</sup>
)−H Alkynylation of Oligopeptides: A Linchpin Approach for Oligopeptide-Drug Conjugation
作者:Tao Liu、Jennifer X. Qiao、Michael A. Poss、Jin-Quan Yu
DOI:10.1002/anie.201706367
日期:2017.8.28
C(sp3)−H alkynylation of oligopeptides was developed with tetrabutylammonium acetate as a key additive. Through molecular design, the acetylene motif served as a linchpin to introduce a broad range of carbonyl‐containing pharmacophores onto oligopeptides, thus providing a chemical tool for the synthesis and modification of novel oligopeptide–pharmacophore conjugates by C−H functionalization. Dipeptide
以乙酸四丁基铵为关键添加剂,开发了钯 (II) 催化的寡肽 C(sp 3 )−H 炔基化反应。通过分子设计,乙炔基序作为关键,将多种含羰基的药效团引入到寡肽上,从而为通过CH官能化合成和修饰新型寡肽-药效团缀合物提供了化学工具。通过该方法合成了与粪甾烷醇和雌二醇的二肽缀合物,其在向核激素受体过度表达的肿瘤细胞靶向药物递送方面具有潜在的应用。
Enantio- and Diastereodivergent Construction of 1,3-Nonadjacent Stereocenters Bearing Axial and Central Chirality through Synergistic Pd/Cu Catalysis
through synergistic Pd/Cu-catalyzed dynamic kinetic asymmetricallenylation with racemic allenylic esters. The protocol is suitable for a wide range of substrates including the challenging allenylic esters with less sterically bulky substituents and provided chiral allenylic products bearing 1,3-nonadjacent stereocenters with high levels of enantio- and diastereoselectivities (up to >20:1 dr and >99% ee)
Stereospecific Synthesis of <i>E</i>-Alkenes through Anti-Markovnikov Hydroalkylation of Terminal Alkynes
作者:Avijit Hazra、Jason Chen、Gojko Lalic
DOI:10.1021/jacs.9b04800
日期:2019.8.14
We have developed a method for stereospecificsynthesis of E-alkenes from terminal alkynes and alkyl iodides. The hydroalkylation reaction is enabled by a cooperative action of copper and nickel catalysts and proceeds with excellent anti-Markovnikov selectivity. We demonstrate the broad scope of the reaction, which can be accomplished in the presence of esters, nitriles, aryl bromides, ethers, alkyl