Insights into the Decomposition of Olefin Metathesis Precatalysts

Abstract

The decomposition of a series of benzylidene, methylidene, and 3-phenylindenylidene complexes has been probed in alcohol solution in the presence of base. Tricyclohexylphosphane-containing precatalysts are shown to yield [RuCl(H)(H2)(PCy3)2] in isopropyl alcohol solutions, while 3-phenylindenylidene complexes lead to η(5)-(3-phenyl)indenyl products. The potential-energy surfaces for the formation of the latter species have been probed using density functional theory studies.

p‐Cymene as Solvent for Olefin Metathesis: Matching Efficiency and Sustainability

“…This is ap articularly challenging reactionb ecause the crossmetathesis may be followed by C=Ci somerization, ap rocess that is detrimentalt og ood yields of the primarily formed cross-metathesis products (Scheme 1). [34][35][36] Remarkable examples are reported in the pharmaceutical development for the ring closing metathesis (RCM) of terminal dienes to produce antiviral macrocycles. In toluene with 2mol %o fH-II ( Figure 1) at 80 8C, the yield of isomerization products reached 54 %.…”

The Future of Ethenolysis in Biobased Chemistry

“…Selectivity decreases owing to the reaction mixture proceeding towards a thermodynamic equilibrium and activity decreases owing to catalyst degradation and product inhibition . Degradation of ruthenium metathesis catalysts is proposed to involve a ruthenium alkylidene species, which is sensitive towards decomposing pathways, such as alcoholysis . Moreover, it is well known that the presence of ethylene in metathesis reactions leads to the unstable ruthenium methylidene (Figure ).…”

The preference for dual-gold(i) catalysis in the hydro(alkoxylation vs. phenoxylation) of alkynes

“…The polarisable continuous model (PCM) was also used in these single-point calculations to model the solvent effects, using chloroform as the solvent. 94,95 The reported free energies in this work include energies obtained at the M06/TZVP level of theory corrected with zero-point energies, thermal corrections and entropy effects evaluated at 298 K and 1 atm (values at 1354 atm can be found Table S1) [96][97][98] with the BP86/SVP method in the gas phase.…”