Multimetallic Ni- and Pd-Catalyzed Cross-Electrophile Coupling To Form Highly Substituted 1,3-Dienes
作者:Astrid M. Olivares、Daniel J. Weix
DOI:10.1021/jacs.7b13601
日期:2018.2.21
synthesis of highly substituted 1,3-dienes from the coupling of vinyl bromides with vinyl triflates is reported for the first time. The coupling is catalyzed by a combination of (5,5'-bis(trifluoromethyl)-2,2'-bipyridine)NiBr2 and (1,3-bis(diphenylphosphino)propane)PdCl2 in the presence of a zinc reductant. This method affords tetra- and penta-substituted 1,3-dienes that would otherwise be difficult
adopted for the synthesis of a natural product containing a 9,10-dihydrophenanthrene skeleton to demonstrate its synthetic utility. One of the extracts from the roots of Salvia hydrangea DC. ex Bentham (Lamiaceae), a 20-norabietane derivative, was selected as the target molecule. The key step forming the 9,10-dihydrophenanthrene skeleton was achieved by the DIBAL-H-promoted cyclization of a silylated
Ligand-Free Iron-Catalyzed Carbon (sp<sup>2</sup>)–Carbon (sp<sup>2</sup>) Oxidative Homo-Coupling of Alkenyllithiums
作者:Zhuliang Zhong、Zhi-Yong Wang、Shao-Fei Ni、Li Dang、Hung Kay Lee、Xiao-Shui Peng、Henry N. C. Wong
DOI:10.1021/acs.orglett.8b03893
日期:2019.2.1
and hexa-substituted 1,3-butadienes. This one-pot procedure involves lithium–iodine exchange to generate the corresponding vinyllithium intermediates. A subsequent iron-catalyzed ligand-free oxidativehomo-coupling eventually led to the formation of 1,3-butadienes in acceptable to excellent isolated yields.
Regioselective Synthesis of Vinyl Halides, Vinyl Sulfones, and Alkynes: A Tandem Intermolecular Nucleophilic and Electrophilic Vinylation of Tosylhydrazones
作者:Devi Prasan Ojha、Kandikere Ramaiah Prabhu
DOI:10.1021/ol503114n
日期:2015.1.2
in tandem at the carbene center to install an electrophile and a nucleophile on the same carbon. This metal-free concept, which is unprecedented, has been illustrated by regioselectivesynthesis of a variety of vinyl halides, vinyl sulfones, and alkyne derivatives.
Nickel‐Catalyzed Conversion of Enol Triflates into Alkenyl Halides
作者:Julie L. Hofstra、Kelsey E. Poremba、Alex M. Shimozono、Sarah E. Reisman
DOI:10.1002/anie.201906815
日期:2019.10.14
A Ni-catalyzed halogenation of enol triflates was developed and it enables the synthesis of a broad range of alkenyl iodides, bromides, and chlorides under mild reaction conditions. The reaction utilizes inexpensive, bench-stable Ni(OAc)2 ⋅4 H2 O as a precatalyst and proceeds at room temperature in the presence of sub-stoichiometric Zn and either 1,5-cyclooctadiene or 4-(N,N-dimethylamino)pyridine
开发了镍催化的烯醇三氟甲磺酸酯卤化反应,能够在温和的反应条件下合成多种烯基碘化物、溴化物和氯化物。该反应使用廉价、实验室稳定的 Ni(OAc)2·4 H2 O 作为预催化剂,并在亚化学计量的 Zn 和 1,5-环辛二烯或 4-(N,N-二甲基氨基) 存在下在室温下进行吡啶。