Acetylene gas has been applied as a feedstock under transition-metal catalysis and photo-redox conditions to produce important chemicals including terminal alkynes, fulvenes, and fluorinated styrene compounds. The reaction discovery process was accelerated through the use of “stop-flow” micro-tubing reactors. This reactor prototype was developed by joining elements from both continuous micro-flow and
C−H Bond Activation for the Synthesis of Heterocyclic Atropisomers Yields Hedgehog Pathway Inhibitors
作者:Gang Shan、Jana Flegel、Houhua Li、Christian Merten、Slava Ziegler、Andrey P. Antonchick、Herbert Waldmann
DOI:10.1002/anie.201809680
日期:2018.10.22
pronounced bioactivity, and methods for their efficient synthesis have gained widespread attention. However, enantioselective synthesis of axially chiral 4‐arylisoquinolones by means of C−Hactivation has not been reported to date. Described here is a rhodium (III)‐catalyzed C−Hbondactivation and annulation for the atroposelective synthesis of axially chiral 4‐arylisoquinolones. The method employs
The catalytic enantioselective [2+2] cycloaddition between quinones and fulvenes was achieved, for the first time, by the use of a chiral copper(II) complex catalyst. The transformation afforded a series of enantiomerically enriched [6,4,5]-tricyclic cyclobutane derivatives in good yields with excellent regio- and stereoselectivities. Furthermore, the [2+2] adducts could be easily converted into formal
Highly Enantioselective Catalytic [6+3] Cycloadditions of Azomethine Ylides
作者:Marco Potowski、Jonathan O. Bauer、Carsten Strohmann、Andrey P. Antonchick、Herbert Waldmann
DOI:10.1002/anie.201204394
日期:2012.9.17
Under control: Highly functionalized chiral annulated piperidines with eight stereocenters are efficiently obtained by means of a highlyenantioselective one‐pot [6+3]/[4+2] sequence. This sequence included the first enantioselective [6+3] cycloaddition of azomethineylides with fulvenes.
metallocene structure with two cyclopentadienyl ligands and two chlorides coordinated to niobium in the oxidation state IV. Chlorides and the centroids of the η5‐bonded cyclopentadienyl rings define a distorted tetrahedron. The cytotoxicity study has demonstrated that substitution with methoxybenzyl groups can lead to highly active species, but the activity strongly varies with the number and positions
一系列新的环官能niobocene二氯化化合物(RCH 2 ç 5 ħ 4)2 NbCl 2(R = MeOCH 2,(CH 2)5 NCH 2,2-MeOC 6 H ^ 4,3-MeOC 6 H ^ 4,4 -MeOC 6 ħ 4,2,4-(MEO)2 C ^ 6 ħ 3,3,4-(MEO)2 C ^ 6 ħ 3,2,4,6-(MEO)3 c ^ 6 ħ 2,3,4- ,5‐(MeO)3c ^ 6 ħ 2,4-FC 6 H ^ 4,4-ME 2 NC 6 H ^ 4)的合成和表征通过电子顺磁共振。通过X射线衍射分析确定了三个结构,揭示了预期的弯曲茂金属结构,其中两个环戊二烯基配体和两个氯化物在氧化态IV下与铌配位。氯化物和η的质心5键合的环戊二烯基环定义为扭曲的四面体。细胞毒性研究表明,用甲氧基苄基取代可产生高活性物种,但活性随苯环中甲氧基的数量和位置而有很大变化。研究中最活跃的物质– 2