Atmospheric oxygen was used for the first time as an oxidant in metal-catalyzed homocoupling of Grignard reagents. These manganese- or iron-catalyzed reactions are efficient, cheap, and eco-friendly. They are applicable to the large-scale synthesis of symmetrical conjugated compounds.
A Simple Nickel Catalyst Enabling an
<i>E</i>
‐Selective Alkyne Semihydrogenation
作者:Niklas O. Thiel、Benyapa Kaewmee、Trung Tran Ngoc、Johannes F. Teichert
DOI:10.1002/chem.201903850
日期:2020.2.3
Stereoselective alkyne semihydrogenations are attractive approaches to alkenes, which are key building blocks for synthesis. With regards to the most atom‐economic reducing agent dihydrogen (H2), only few catalysts for the challenging E‐selectivealkyne semihydrogenation have been disclosed, each with a unique substrate scope profile. Here, we show that a commercially available nickel catalyst facilitates
立体选择性炔烃半氢化是制备烯烃的有吸引力的方法,烯烃是合成的关键组成部分。对于最具原子经济性的还原剂二氢(H 2 ),仅公开了少数用于具有挑战性的E-选择性炔烃半氢化的催化剂,每种催化剂都具有独特的底物范围特征。在这里,我们表明,市售的镍催化剂促进了多种取代内炔的E-选择性炔烃半氢化。这产生了一个简单且广泛适用的整体方案,用于使用 H 2立体选择性地访问E-烯烃,这可以作为通用的合成方法。
Electrochemical C−H/N−H Functionalization for the Synthesis of Highly Functionalized (Aza)indoles
their prevalence in nature and their broad utility in pharmaceutical industry. Reported herein is an unprecedented noble‐metal‐ and oxidant‐free electrochemical method for the coupling of (hetero)arylamines with tethered alkynes to synthesize highly functionalized indoles, as well as the more challenging azaindoles.
Hydrophosphorylation of Alkynes Catalyzed by Palladium: Generality and Mechanism
作者:Tieqiao Chen、Chang-Qiu Zhao、Li-Biao Han
DOI:10.1021/jacs.8b00550
日期:2018.2.28
H-phosphonates disfavored the addition. For H-phosphinates and secondary phosphine oxides, Pd/dppe/Ph2P(O)OH was the catalyst of choice, which led to highly regioselective formation of the Markovnikov adducts. By using Pd(PPh3)4 as the catalyst, hypophosphinic acid added to terminal alkynes to give the corresponding Markovnikov adducts. Phosphinic acids, phosphonic acid, and its monoester were not applicable
An efficient base-catalyzed double addition of H-phosphine oxides to alkynes
作者:Aya Yoshimura、Yuta Saga、Yuki Sato、Akiya Ogawa、Tieqiao Chen、Li-Biao Han
DOI:10.1016/j.tetlet.2016.06.079
日期:2016.7
An efficient base-catalyzed double addition of H-phosphine oxides to alkynes is developed. In the presence of a catalytic amount of a base, the addition of various H-phosphine oxides to both aromatic and aliphatic alkynes took place efficiently to produce the corresponding bisphosphoryl compounds in excellent yields. This method provides an easy direct way to prepare bisphosphine oxides that are of