Half-Sandwich Ruthenium Carbene Complexes Link<i>trans</i>-Hydrogenation and<i>gem</i>-Hydrogenation of Internal Alkynes
作者:Alexandre Guthertz、Markus Leutzsch、Lawrence M. Wolf、Puneet Gupta、Stephan M. Rummelt、Richard Goddard、Christophe Farès、Walter Thiel、Alois Fürstner
DOI:10.1021/jacs.8b00665
日期:2018.2.28
E-alkenes are formed by trans-delivery of the two H atoms of H2. A combinedexperimental and computational study now provides a comprehensive mechanistic picture: a metallacyclopropene (η2-vinyl complex) is primarily formed, which either evolves into the E-alkene via a concerted process or reacts to give a half-sandwich ruthenium carbene; in this case, one of the C atoms of the starting alkyne is converted
<i>trans</i>
‐Hydroboration of Propargyl Alcohol Derivatives and Related Substrates
作者:Lauren E. Longobardi、Alois Fürstner
DOI:10.1002/chem.201902228
日期:2019.8
in good to excellent levels of regio‐ as well as stereoselectivity, provided that the triple bond bears one linear and one singly‐branched substituent. In such cases, the reaction follows an unusual trans‐addition mode and places the boron entity distal to the branching point. The resulting alkenyl boronates, which are difficult to make otherwise, can be engaged in numerous enabling downstream processes
Formation of Ruthenium Carbenes by<i>gem</i>-Hydrogen Transfer to Internal Alkynes: Implications for Alkyne<i>trans</i>-Hydrogenation
作者:Markus Leutzsch、Larry M. Wolf、Puneet Gupta、Michael Fuchs、Walter Thiel、Christophe Farès、Alois Fürstner
DOI:10.1002/anie.201506075
日期:2015.10.12
trans‐hydrogenation of internalalkynes catalyzed by Cp*Ru} complexes were gained by para‐hydrogen (p‐H2) induced polarization (PHIP) transfer NMR spectroscopy. It was found that the productive trans‐reduction competes with a pathway in which both H atoms of H2 are delivered to a single alkyne C atom of the substrate while the second alkyne C atom is converted into a metal carbene. This “geminal hydrogenation”
Hydrogenative Cycloisomerization and Sigmatropic Rearrangement Reactions of Cationic Ruthenium Carbenes Formed by Catalytic Alkyne
<i>gem</i>
‐Hydrogenation
作者:Tobias Biberger、Stephan N. Hess、Markus Leutzsch、Alois Fürstner
DOI:10.1002/anie.202113827
日期:2022.2.14
unprecedented hydrogenation reactions are disclosed, commencing with geminal delivery of both H-atoms of H2 to the triple bond of a propargyl alcohol derivative. When catalyzed with cationicrutheniumcomplexes, the resulting pianostool carbenes are so “hot” that they are readily intercepted by tethered nucleophiles, resulting in cycloisomerization or [2,3]-sigmatropic rearrangement reactions.
Efficient Transformation of Methyl Propargyl Ethers into α,β-Unsaturated Ketones
作者:Yukitoshi Fukuda、Kiitiro Utimoto
DOI:10.1246/bcsj.64.2013
日期:1991.6
Methyl propargyl ethers, obtained from carbonyl compounds by successive treatment with an acetylide and MeI, were easily converted to the corresponding α,β-unsaturated ketone by regioselective hydration of acetylenic moiety followed by elimination of methanol under the catalytic action of Au(III).
通过用乙炔和 MeI 连续处理从羰基化合物中获得的甲基炔丙基醚,通过炔部分的区域选择性水合,然后在 Au(III) 的催化作用下消除甲醇,很容易转化为相应的 α,β-不饱和酮。