A regiodivergent nickel-catalyzed hydrocyanation of 1-aryl-4-silyl-1,3-diynes is reported. When appropriate bisphosphine and phosphine–phosphite ligands are applied, the same starting materials can be converted into two different enynyl nitriles with good yields and high regioselectivities. The DFT calculations unveiled that the structural features of different ligands bring divergent alkyne insertion
Chemoselective Cobalt(I)-Catalyzed Cyclotrimerization of (Un)Symmetrical 1,3-Butadiynes for the Synthesis of 1,2,4-Regioisomers
作者:Sebastian M. Weber、Gerhard Hilt
DOI:10.1021/acs.orglett.9b01281
日期:2019.6.7
The cobalt(I)-catalyzed cyclotrimerization of (un)symmetrical 1,4-disubstituted 1,3-butadiynes is presented. In the case of unsymmetrical 1,3-butadiynes, this reaction can generate eight 1,2,4-substituted and four 1,3,5-substituted isomers. A single 1,2,4-substituted isomer was formed in excellent yields (up to 99%) and exclusive regioselectivities (>99:1) when symmetrical or a 1,3-butadiyne with an
are rare representatives of such species, but few interesting crystal-to-crystal reactions have been recently reported for them. Herein, we present 11 newX-raystructures of 1-halopolyynes, nearly doubling the number of such compounds characterized with the use of single-crystal X-ray diffraction. The influence of an end-group on packing motifs in crystalstructures of the 1-halopolyynes were thoroughly
聚炔是具有两个或多个共轭碳-碳三键的化合物。此类分子通常被视为carbyne的模型-碳的一种假设的一维同素异形形式。1-卤代多炔是此类物种的稀有代表,但最近很少有人报道它们有趣的晶体间反应。在本文中,我们介绍了1-卤代聚炔的11种新X射线结构,几乎使使用单晶X射线衍射表征的此类化合物的数量增加了一倍。彻底检查了端基对1-卤代聚炔的晶体结构中的堆积图案的影响。特别是在理论计算的支持下分析了卤素键强度与聚炔链长的关系。此外,复合CNC 8 I是目前为止最长的1-halopolyyne,其特征是使用Rentgenoostructural analysis。除此之外,化合物NO 2 C 6 Br和MeC(O)C 6 Br是通过X射线单晶衍射表征的第一个1-溴己三炔。
Cobalt-Catalyzed Regio- and Stereoselective Hydrosilylation of 1,3-Diynes To Access Silyl-Functionalized 1,3-Enynes
作者:Hui Leng Sang、Yongyi Hu、Shaozhong Ge
DOI:10.1021/acs.orglett.9b01836
日期:2019.7.5
A regio- and stereoselective hydrosilylation of 1,3-diynes has been developed relying on catalysts generated from bench-stable Co(acac)2 and dppp ligand. A variety of symmetrical and unsymmetrical 1,3-diynes undergo this transformation, yielding the corresponding silyl-functionalized 1,3-enynes in high yields with excellent regioselectivity. Gram-scale reactions and further transformations of the silyl-containing
reaction of terminal 1,3-diynes with 1,1-dichloro-2,2,2-trifluoroethane (CF3CHCl2) using ethanolamine as ligand gave trifluoroethylated unsymmetrical 1,3-diynes in moderate to good yields. The reaction were carried out under mild conditions, and were easy to operate. Aryl groups with weak electron-withdrawing group or electron-donating group, and alkyl substitutents at terminal 1,3-diynes were tolerated