Ethenolysis: A Green Catalytic Tool to Cleave Carbon–Carbon Double Bonds

Abstract

Remarkable innovations have been made in the field of olefin metathesis due to the design and preparation of new catalysts. Ethenolysis, which is cross-metathesis with ethylene, represents one catalytic transformation that has been used with the purpose of cleaving internal carbon-carbon double bonds. The objectives were either the ring opening of cyclic olefins to produce dienes or the shortening of unsaturated hydrocarbon chains to degrade polymers or generate valuable shorter terminal olefins in a controlled manner. This Review summarizes several aspects of this reaction: the catalysts, their degradation in the presence of ethylene, some parameters driving their productivity, the side reactions, and the applications of ethenolysis in organic synthesis and in potential industrial applications.

The Future of Ethenolysis in Biobased Chemistry

“…The CAAC catalysts show the highest TONs reported with these ethylene purities; however, the margin with the Grubbs 1 st generation catalysts is small with TONs of 35 000 and 26 000 for Ru11 and Ru17 (Table , entries 1 and 2) and 24 800 and 22 300 for Ru1 and Ru3 (Table , entries 3 and 4). It has been noted before that the CAAC catalysts appear to be by far the most efficient ones; however, when the ethylene purity is taken into account the improvement over traditional catalysts is small.…”

“…This makes substrate purity an important factor to reach high TONs when low loading is used. However, the extent of the influence of substrate purity was not investigated, which made comparison of reported results difficult . The use of ethenolysis on biobased substrates has not yet been thoroughly reviewed.…”

Bis(Cyclic Alkyl Amino Carbene) Ruthenium Complexes: A Versatile, Highly Efficient Tool for Olefin Metathesis

“…Those complexes show, in the majority of cases, a low level of degenerate (unproductive) metathesis and low stability of ruthenium methylidenes. This characteristic makes them practically useless in the industrially important cross‐metathesis of unsaturated fatty acid derivatives such as methyl oleate (MO, 7 ) with ethylene, commonly referred to as ethenolysis 14. Linear α‐olefins (LAOs, for example 8 and 9 , Scheme 1), obtained as a result of ethenolysis, can be easily transformed to higher added‐value products 15.…”

Recent Advancements in Stereoselective Olefin Metathesis Using Ruthenium Catalysts

“…However, any CM is in equilibrium with the back reaction, ethenolysis, which is the cleavage of an internal olefin to generate two terminal olefins. Furthermore, ethenolysis of internal olefins has received attention as a method to access materials and fuels from renewable sources such as seed oil derivatives [50][51][52][53][54][55]. It was postulated that 6 could be employed in a Z-selective ethenolysis as a method to purify E-olefins.…”