activated N-heterocyclic carbene-Ni(0) as a catalyst and R3SiH as silane (IPrCl, syn- : anti-selectivity from up to 98 : 2 to 7 : 93 by Z = O, NH vs. NMs, R1 = n-pentyl). Heterocycles bearing homoallylsilane rather than vinylsilane was obtained chemoselectively. The undesired yet highly competitive reactivity was suppressed, like direct hydrosilylation of alkene and alkyne concurrently. Optionally, the
[(NHC)Ni
<sup>II</sup>
H]‐Catalyzed Cross‐Hydroalkenylation of Cyclopropenes with Alkynes: Cyclopentadiene Synthesis by [(NHC)Ni
<sup>II</sup>
]‐Assisted C−C Rearrangement
作者:Jian‐Qiang Huang、Chun‐Yu Ho
DOI:10.1002/anie.201901255
日期:2019.4.16
achieved for the first time by using new [(NHC)Ni(allyl)]BArF catalysts (NHC=N‐heterocyclic carbenes). By controlling the (NHC)NiIIH relative insertion reactivity with cyclopropene and alkyne, a broad scope of cyclopentadienes was obtained with highly selectively. The structural features of the new (NHC)NiII catalyst were important for the success of the reaction. The mild reaction conditions employed may
通过使用新的[(NHC)Ni(烯丙基)] BAr F催化剂(NHC = N杂环卡宾),首次使用环丙烯和炔烃作为底物对实现了交叉氢烯基化/重排级联反应(HARC )。通过控制(NHC)Ni II H与环丙烯和炔烃的相对插入反应性,可以高度选择性地获得宽范围的环戊二烯。新型(NHC)Ni II催化剂的结构特征对于反应成功至关重要。所采用的温和反应条件可以作为探索(NHC)Ni II辅助的乙烯基环丙烷重排反应性的入口。
作者:Xuefeng Yong、Elvis Wang Hei Ng、Zibo Zhen、Xiulian Lin、Weiwei Gao、Chun‐Yu Ho
DOI:10.1002/adsc.202000718
日期:2020.10.6
NHC‐Nickel(0) catalyzed 1,3‐ and 1,4‐diastereodivergenthydroacylative heteroenyne cyclization with aldehydes was achieved (Syn‐:Anti‐, switchable from up to 1:99 to 98:2). Both sets of heterocyclic diastereomers are accessible via this route, with a high γ‐:α‐enone structure ratio. Preliminary DFT investigations indicated that the manipulation of the N‐substituent exerts a direct influence on the
作者:Daniela Kampen、Arnaud Ladépêche、Gerrit Claßen、Benjamin List
DOI:10.1002/adsc.200800036
日期:2008.5.5
Aldehydes react with silyl ethers or the corresponding alcohols and allylsilanes in the presence of catalytic amounts of 2,4-dinitrobenzenesulfonic acid (DNBA) to provide a wide range of homoallylic ethers in moderate to high yields.
Ruthenium dihydride complexes as enyne metathesis catalysts
作者:Martin A. Dolan、Alexandre D.C. Dixon、John D. Chisholm、Daniel A. Clark
DOI:10.1016/j.tetlet.2018.11.016
日期:2018.12
Ruthenium–catalyzedenyne metathesis is a reliable and efficient method for the formation of 1,3-dienes, a common structural motif in synthetic organic chemistry. The development of new transition-metal complexes competent to catalyze enyne metathesis reactions remains an important research area. This report describes the use of ruthenium (IV) dihydride complexes with the general structure RuH2Cl2(PR3)2