Ruthenium‐Catalyzed Isomerization of Terminal Olefins: Applications to Synthesis

Abstract

In, out, olefin about: A ruthenium hydride complex derived from the Grubbs second‐generation metathesis catalyst has proven to be an efficient catalyst for the selective isomerization of terminal olefins to the corresponding propenyl derivatives (see scheme). This methodology has been applied in a number of syntheses to enable access to complex natural products. Cy=cyclohexyl, Mes=mesityl, MOM=methoxymethyl.

Aromatic Enamide/Ene Metathesis toward Substituted Indoles and Its Application to the Synthesis of Indomethacins

“…[7] An isomerization/RCMbased strategy [8] and RCM/isomerization [9] have also been reported. Therefore, we decided to explore our enamide/ene metathesis in much more detail and establish a flexible method for the synthesis of 2,3-disubstituted indoles with a variety of substituents under mild conditions.…”

New Insights on Kinetic Versus Thermodynamic Ratios in Catalyzed Alkene Isomerization

“…Alkene isomerization is an atom economical process, which has been useful in transformations such as those of allyl alcohols to the corresponding carbonyl analogues [1,2], allyl ethers to enol ethers [3], allyl amines to enamines [4], and most recently in the migration of double bonds in synthetic application using a modified version Grubbs' metathesis catalyst [5,6]. Isomerization catalysts using a plethora of metals and ligands have shown a wide variety of reactivity, however an obstacle in transition metal catalyzed isomerization of alkenes is the selective formation of cis-or trans-olefin products, rather than mixtures of the two [7,8], in some cases along with starting material.…”

(Enantio)selective Hydrogen Autotransfer: Ruthenium‐Catalyzed Synthesis of Oxazolidin‐2‐ones from Urea and Diols

“…In this case, reduction of the terminal C = Cb ond was also observed, providing the saturated oxazolidin-2-one 3g in 65 %y ield (entry 8). Thew ell-known ability of ruthenium complexes to promote the isomerization or reduction of multiple bonds [11] implies that the hydrogen extracted in the first step is used in both imine and C=Cb ond reduction.…”