Alkene Metathesis Catalysis: A Key for Transformations of Unsaturated Plant Oils and Renewable Derivatives

Abstract

-This account presents the importance of ruthenium-catalysed alkene cross-metathesis for the catalytic transformations of biomass derivatives into useful intermediates, especially those developed by the authors in the Rennes (France) catalysis team in cooperation with chemical industry. The cross-metathesis of a variety of functional alkenes arising from plant oils, with acrylonitrile and fumaronitrile and followed by catalytic tandem hydrogenation, will be shown to afford linear amino acid derivatives, the precursors of polyamides. The exploration of crossmetathesis of bio-sourced unsaturated nitriles with acrylate with further catalytic hydrogenation has led to offer an excellent route to a,x-amino acid derivatives. That of fatty aldehydes has led to bifunctional long chain aldehydes and saturated diols. Two ways of access to functional dienes by ruthenium-catalyzed ene-yne cross-metathesis of plant oil alkene derivatives with alkynes and by cross-metathesis of bio-sourced alkenes with allylic chloride followed by catalytic dehydrohalogenation, are reported. Ricinoleate derivatives offer a direct access to chiral dihydropyrans and tetrahydropyrans via ring closing metathesis. Cross-metathesis giving value to terpenes and eugenol for the straightforward synthesis of artificial terpenes and functional eugenol derivatives without C=C bond isomerization are described.Résumé -Catalyse de métathèse d'oléfines : une clé pour des transformations d'huiles végétales insaturées et de substances renouvelables -Cet article présente l'importance de la réaction de métathèse croisée des oléfines par catalyse au ruthénium pour la transformation de dérivés de la biomasse en produits utiles pour l'industrie. Il constitue une revue des principaux travaux réalisés dans ce domaine par les auteurs dans leur équipe de catalyse à Rennes (France) en coopération avec l'industrie chimique. La métathèse croisée d'une variété d'oléfines fonctionnelles issues des huiles végétales avec l'acrylonitrile et le fumaronitrile, suivie d'une hydrogénation tandem conduit à des dérivés d'amino acides linéaires, précurseurs de polyamides par polycondensation. L'exploration de la métathèse croisée de nitriles insaturés bio-sourcés avec des acrylates a conduit à des dérivés d'a,x-amino acides, tandis que les aldéhydes gras ont permis un accès rapide à des aldéhydes bifonctionnalisés à longue chaîne et à des diols saturés. Deux voies d'accès à des diènes conjugués fonctionnels impliquant des réactions de métathèse catalysées par le ruthénium à partir d'oléfines issues de la biomasse sont décrites : l'une par métathèse croisée avec un alcyne, l'autre par métathèse croisée avec un chlorure allylique suivie Dedicated to the memory of Yves Chauvin, a great and inspiring pioneer in organometallic catalysis

Synthesis of New Dehydrodieugenol Derivatives via Olefin Cross Metathesis and In Vitro Evaluation of Their Trypanocidal Activity

“…Indeed, only one stereoisomer was detected and the value of the coupling constant of 15.6 Hz between the two olefinic protons indicated that the cross metathesis was (E)-selective. It is noteworthy that this (E) stereoselectivity is perfectly in line with that observed during cross metathesis of 2a with the monomeric eugenol [42][43][44].…”

“…The synthesis of biseugenol 1 was achieved via the oxidative coupling of eugenol in the presence of K 3 [Fe(CN) 6 ] as oxidant [46], and led to a 36% isolated yield of 1 with high purity after recrystallization (see experimental section). We have previously shown that the cross metathesis of eugenol with acrylates [42][43][44] was efficiently carried out in the presence of the second generation Hoveyda ruthenium catalyst Ru1 [47]. The isomerization of allylbenzene derivatives including 4-hydroxyphenylpropanoids in the presence of ruthenium olefin metathesis catalysts has been extensively described by van Otterlo [48], who suggested that the utilization of an isomerization inhibitor should be recommended to avoid this competing reaction leading to undesired metathesis products.…”

Synthesis of New Dehydrodieugenol Derivatives via Olefin Cross Metathesis and In Vitro Evaluation of Their Trypanocidal Activity

“…Indeed, only one stereoisomer was detected and the value of the coupling constant of 15.6 Hz between the two olefinic protons indicated that the cross metathesis was (E)-selective. It is noteworthy that this (E) stereoselectivity is perfectly in line with that observed during cross metathesis of 2a with the monomeric eugenol [42][43][44].…”

“…The synthesis of biseugenol 1 was achieved via the oxidative coupling of eugenol in the presence of K 3 [Fe(CN) 6 ] as oxidant [46], and led to a 36% isolated yield of 1 with high purity after recrystallization (see experimental section). We have previously shown that the cross metathesis of eugenol with acrylates [42][43][44] was efficiently carried out in the presence of the second generation Hoveyda ruthenium catalyst Ru1 [47]. The isomerization of allylbenzene derivatives including 4-hydroxyphenylpropanoids in the presence of ruthenium olefin metathesis catalysts has been extensively described by van Otterlo [48], who suggested that the utilization of an isomerization inhibitor should be recommended to avoid this competing reaction leading to undesired metathesis products.…”

Preparation of Musk‐Smelling Macrocyclic Lactones from Biomass: Looking for the Optimal Substrate Combination

“…[11] In the next experiment (entry 4) the addition of TFQ was tested and an increaseofthe RCM selectivity was observed. As expected, [24,25] in more concentrated solutiona ni ncreased production of the oligomeric products was observed. Finally,d ifferentd iene concentrations (3 and 7.5 mm)w ere used.…”

“…Finally,d ifferentd iene concentrations (3 and 7.5 mm)w ere used. As expected, [24,25] in more concentrated solutiona ni ncreased production of the oligomeric products was observed. Finally,t he following conditions were selected as optimal (Scheme 3): toluene, c = 1.5 mm,5 0 8C, 5h,2mol % Scheme1.Twop ossible paths in the synthesis of am acrocyclicmusk from biomass and potential advantages and disadvantages associatedw ith both paths.…”

Accessing Monomers, Surfactants, and the Queen Bee Substance by Acrylate Cross‐Metathesis of Long‐Chain Alkenones

“…As shown, the reaction gave 99% conversion after 30 min which is a similar time frame observed for the previous 2-butene/alkenone cross-metathesis (99.5% after 30 min) [18], despite the significant electronic differences between 2-butene and methyl acrylate which can greatly influence olefin metathesis reactivity [48]. The rate of conversion for our alkenone metathesis is also identical to that reported for the same reaction with methyl oleate under similar conditions [19,20], suggesting that lipid alkene geometry (trans for alkenones vs. cis for methyl oleate) is not limiting in this respect.…”

Synthesis of New Dehydrodieugenol Derivatives via Olefin Cross Metathesis and In Vitro Evaluation of Their Trypanocidal Activity

“…Indeed, only one stereoisomer was detected and the value of the coupling constant of 15.6 Hz between the two olefinic protons indicated that the cross metathesis was (E)-selective. It is noteworthy that this (E) stereoselectivity is perfectly in line with that observed during cross metathesis of 2a with the monomeric eugenol [42][43][44].…”

“…The synthesis of biseugenol 1 was achieved via the oxidative coupling of eugenol in the presence of K 3 [Fe(CN) 6 ] as oxidant [46], and led to a 36% isolated yield of 1 with high purity after recrystallization (see experimental section). We have previously shown that the cross metathesis of eugenol with acrylates [42][43][44] was efficiently carried out in the presence of the second generation Hoveyda ruthenium catalyst Ru1 [47]. The isomerization of allylbenzene derivatives including 4-hydroxyphenylpropanoids in the presence of ruthenium olefin metathesis catalysts has been extensively described by van Otterlo [48], who suggested that the utilization of an isomerization inhibitor should be recommended to avoid this competing reaction leading to undesired metathesis products.…”

Preparation of Musk‐Smelling Macrocyclic Lactones from Biomass: Looking for the Optimal Substrate Combination

“…[11] In the next experiment (entry 4) the addition of TFQ was tested and an increaseofthe RCM selectivity was observed. As expected, [24,25] in more concentrated solutiona ni ncreased production of the oligomeric products was observed. Finally,d ifferentd iene concentrations (3 and 7.5 mm)w ere used.…”

“…Finally,d ifferentd iene concentrations (3 and 7.5 mm)w ere used. As expected, [24,25] in more concentrated solutiona ni ncreased production of the oligomeric products was observed. Finally,t he following conditions were selected as optimal (Scheme 3): toluene, c = 1.5 mm,5 0 8C, 5h,2mol % Scheme1.Twop ossible paths in the synthesis of am acrocyclicmusk from biomass and potential advantages and disadvantages associatedw ith both paths.…”

Accessing Monomers, Surfactants, and the Queen Bee Substance by Acrylate Cross‐Metathesis of Long‐Chain Alkenones

“…As shown, the reaction gave 99% conversion after 30 min which is a similar time frame observed for the previous 2-butene/alkenone cross-metathesis (99.5% after 30 min) [18], despite the significant electronic differences between 2-butene and methyl acrylate which can greatly influence olefin metathesis reactivity [48]. The rate of conversion for our alkenone metathesis is also identical to that reported for the same reaction with methyl oleate under similar conditions [19,20], suggesting that lipid alkene geometry (trans for alkenones vs. cis for methyl oleate) is not limiting in this respect.…”

Synthesis of New Dehydrodieugenol Derivatives via Olefin Cross Metathesis and In Vitro Evaluation of Their Trypanocidal Activity

“…Indeed, only one stereoisomer was detected and the value of the coupling constant of 15.6 Hz between the two olefinic protons indicated that the cross metathesis was (E)-selective. It is noteworthy that this (E) stereoselectivity is perfectly in line with that observed during cross metathesis of 2a with the monomeric eugenol [42][43][44].…”

“…The synthesis of biseugenol 1 was achieved via the oxidative coupling of eugenol in the presence of K 3 [Fe(CN) 6 ] as oxidant [46], and led to a 36% isolated yield of 1 with high purity after recrystallization (see experimental section). We have previously shown that the cross metathesis of eugenol with acrylates [42][43][44] was efficiently carried out in the presence of the second generation Hoveyda ruthenium catalyst Ru1 [47]. The isomerization of allylbenzene derivatives including 4-hydroxyphenylpropanoids in the presence of ruthenium olefin metathesis catalysts has been extensively described by van Otterlo [48], who suggested that the utilization of an isomerization inhibitor should be recommended to avoid this competing reaction leading to undesired metathesis products.…”

Preparation of Musk‐Smelling Macrocyclic Lactones from Biomass: Looking for the Optimal Substrate Combination

“…[11] In the next experiment (entry 4) the addition of TFQ was tested and an increaseofthe RCM selectivity was observed. As expected, [24,25] in more concentrated solutiona ni ncreased production of the oligomeric products was observed. Finally,d ifferentd iene concentrations (3 and 7.5 mm)w ere used.…”

“…Finally,d ifferentd iene concentrations (3 and 7.5 mm)w ere used. As expected, [24,25] in more concentrated solutiona ni ncreased production of the oligomeric products was observed. Finally,t he following conditions were selected as optimal (Scheme 3): toluene, c = 1.5 mm,5 0 8C, 5h,2mol % Scheme1.Twop ossible paths in the synthesis of am acrocyclicmusk from biomass and potential advantages and disadvantages associatedw ith both paths.…”

Accessing Monomers, Surfactants, and the Queen Bee Substance by Acrylate Cross‐Metathesis of Long‐Chain Alkenones

“…As shown, the reaction gave 99% conversion after 30 min which is a similar time frame observed for the previous 2-butene/alkenone cross-metathesis (99.5% after 30 min) [18], despite the significant electronic differences between 2-butene and methyl acrylate which can greatly influence olefin metathesis reactivity [48]. The rate of conversion for our alkenone metathesis is also identical to that reported for the same reaction with methyl oleate under similar conditions [19,20], suggesting that lipid alkene geometry (trans for alkenones vs. cis for methyl oleate) is not limiting in this respect.…”