Palladium-Catalyzed Asymmetric Ring Expansion of Allenylcyclobutanols: An Asymmetric Wagner−Meerwein Shift
作者:Barry M. Trost、Jia Xie
DOI:10.1021/ja0602501
日期:2006.5.1
In this study, we developed a palladium-catalyzed atom economic asymmetricWagner-Meerweinshift of allenylcyclobutanol substrates. It is an excellent method for creating functionalized cyclopentanones with an alpha-chiral O-tertiary center by ring expansion of allenylcyclobutanols. This reaction was initiated by hydropalladation and afforded excellent enantioselectivity as well as atom economy. This
[(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。
Rhodium catalysed synthesis of illudalanes
作者:S.J. Neeson、P.J. Stevenson
DOI:10.1016/s0040-4020(01)85134-6
日期:1989.1
A short, regiospecific route to pterosin Z and calomelanolactone is presented in which the key step is a rhodiumcatalysed intramolecular cycloaddition.
Palladium-Catalyzed Diastereo- and Enantioselective Wagner−Meerwein Shift: Control of Absolute Stereochemistry in the C−C Bond Migration Event
作者:Barry M. Trost、Jia Xie
DOI:10.1021/ja7111299
日期:2008.5.1
Inducing absolute stereochemistry in Wagner-Meerwein shifts was examined in a ring expansion protocol. Initiated by generation of a pi-allylpalladium intermediate by hydropalladation of allenes, the ring expansion of allenylcyclobutanol substrates proceeded with excellent diastereo- and enantioselectivities. The results demonstrate that, during the C-C bond migration process, our chiral catalysts can control the stereochemistry of both the pi-allylpalladium intermediate and the corresponding migration bond. Moreover, the stereochemical outcome of the reaction can be rationalized very well with the working model of the chiral catalyst. The method provides an efficient way to synthesize highly substituted cyclopentanones with an alpha-chiral O-tertiary center which has various synthetic applications.
Indium(III)-Catalyzed Hydrative Cyclization of 1,7-Diynyl Ethers
作者:Amanda L. Gibeau、John K. Snyder
DOI:10.1021/ol201624b
日期:2011.8.19
A new hydrative cyclization of 1,7- and 1,8-diynyl ethers is reported. Using catalytic InI(3) and p-TSA as a cocatalyst, several 2,2-disubstituted tetrahydrofurans with exocyclic enone appendages were prepared. Reaction optimization and scope, mechanistic insight, and further transformation to a C-nucleoside analog are presented.