Recent Advances and Prospects in the Tishchenko Reaction

Dhanya, Raju; Shilpa, Thomas; Saranya, Salim; Anilkumar, Gopinathan

doi:10.1002/slct.201902776

Cited by 13 publications

(11 citation statements)

References 88 publications

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“…The Tishchenko reaction (or the Claisen–Tishchenko reaction), which has been known for more than a century, is a most atom-efficient and waste-free strategy to synthesize symmetric carboxylic esters by the dimerization of aldehydes . To date, a number of metal catalysts including aluminum alkoxides, alkali and alkaline earth metal oxides, transition metals, and actinide complexes have been developed for this reaction.…”

Section: Resultsmentioning

confidence: 99%

“…The Tishchenko reaction (or the Claisen−Tishchenko reaction), which has been known for more than a century, is a most atom-efficient and waste-free strategy to synthesize symmetric carboxylic esters by the dimerization of aldehydes. 16 To date, a number of metal catalysts including aluminum alkoxides, 17 alkali and alkaline earth metal oxides, 18 transition metals, 19 and actinide complexes 20 have been developed for this reaction. To the best of our knowledge, a limited number of rare-earth metal complexes are proven to be useful in the dimerization of aldehydes, such as and the low efficiency in the case of heteroaromatic and aliphatic aldehydes limited their further application.…”

Section: ■ Results and Discussionmentioning

confidence: 99%

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Synthesis and Characterization of N,N,C and N,N,O Tridentate β-Diketiminato Rare-Earth Metal Alkyl Complexes and Their Catalytic Performances on the Dimerization of Aldehydes or Terminal Alkynes

et al. 2022

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Three β-diketiminato proligands incorporating a thiophene or tetrahydrofuran heterocyclic group, H2 L1 , H2 L2 , and HL3 (MeC(NDipp)CHC(Me)N(CH2)n-2-(HCG), HCG = C4H2S, n = 2, L1 ; n = 1, L2 ; HCG = C4H7O, n = 1, L3 ; Dipp = 2,6- i Pr2C6H3), have been developed. Unusual N,N,C tridentate β-diketiminato rare-earth metal monoalkyl complexes L1 RE(CH2SiMe3)(thf) (RE = Y (1a), Er (1b), Yb (1c), Lu (1d), thf = tetrahydrofuran) and L2 Yb(CH2SiMe3)(thf) (2c) were achieved unexpectedly by the reactions of RE(CH2SiMe3)3(thf)2 with H2 L1 and H2 L2 , respectively. In this process, the C–H bond activation of the thiophene ring occurred. In sharp contrast, the treatment of RE(CH2SiMe3)3(thf)2 with a tetrahydrofuran-functionalized β-diketiminato proligand HL3 , under the same conditions, gave five-coordinate N,N,O tridentate β-diketiminato rare-earth metal dialkyl complexes L3 RE(CH2SiMe3)2 (RE = Y (3a), Er (3b), and Yb (3c)). In addition, their unique catalytic performances have been described. The monoalkyl complexes exhibited high efficiency toward the dimerization of various aldehydes, providing a wide range of carboxylic esters in good to high yields under mild conditions. The dialkyl complexes could promote the head-to-head dimerization of terminal alkynes to afford conjugated 1,4-disubstituted enynes with excellent regio- and stereoselectivity (up to 100% Z-selectivity). More importantly, a rare type of rare-earth metal complexes [{L 3RE(μ-CCPh)}2(μ-η2:η2-PhCCCCPh)] (RE = Y (6a), Er (6b)) containing two bridging alkynyl groups and a Z-butatrienediyl fragment were isolated and characterized by the reaction of N,N,O tridentate rare-earth metal dialkyls with phenylacetylene, which is unarguably responsible for the outcome of Z-configured enynes during alkyne dimerization.

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Section: Resultsmentioning

confidence: 99%

Section: ■ Results and Discussionmentioning

confidence: 99%

Synthesis and Characterization of N,N,C and N,N,O Tridentate β-Diketiminato Rare-Earth Metal Alkyl Complexes and Their Catalytic Performances on the Dimerization of Aldehydes or Terminal Alkynes

et al. 2022

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“…Known for about 130 years, the Tishchenko reaction has been viewed as a promising candidate for a universal, atom efficient method of preparing esters, though it has long been plagued with selectivity issues when combining two distinct aldehyde species, with four possible products from each two‐aldehyde combination [99–101] . Catalysis of this reaction by Lewis acids and transition metals has been well documented, and recently its scope has been expanded to include several s‐block metal catalysts, which show that this method of ester formation can also be carried out by simple alkali metal tert ‐butoxides, hydrides or amides [102–104] . Relevant to the research reported herein is that among these new main group Tishchenko catalysts is work by Hill showing alkaline earth metal pre‐catalysts bearing NacNac ligands [105] .…”

Section: Resultsmentioning

confidence: 99%

Crystallographic Characterisation of Organolithium and Organomagnesium Intermediates in Reactions of Aldehydes and Ketones

Mulvey

Lynch

Kennedy

et al. 2022

Helvetica Chimica Acta

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We report reactions of LiNacNac and NacNacMg(TMP) with common organic substrates (TMP=2,2,6,6‐tetramethylpiperidide). Using bulky β‐diketiminate compound NacNac (Me, Dipp), we have trapped metalated intermediates amenable to X‐ray crystallographic study. LiNacNac and acetone produced the NacNac‐free hexameric diacetone alkoxide [{LiO(MeC(=O)CH2C(Me)2}6]; whereas pinacolone gave the simple monomeric donor–acceptor complex [Li{(MeCN‐2,6‐iPr2C6H3)2CH}{O=C(Me)tBu}]. Benzaldehyde produced dimeric [Li{(MeCN‐2,6‐iPr2C6H3)2CC(=O)Ph}{O=C(Ph)OCH2Ph}]2, where one benzaldehyde molecule has inserted in to the γ‐carbon position of the NacNac ligand, with a molecule of benzyl benzoate derived from a Tishchenko reaction of the aldehyde acting as a terminal donor to lithium. Tetranuclear, mixed dimer [{LiO(MeCN‐2,6‐iPr2C6H3)2CH‐CH(Ph)}2{LiO(PhC(=O)}2] containing the same modified NacNac ligand was the fortuitous product from repeating the reaction of LiNacNac and benzaldehyde in a solution presumably contaminated with benzoic acid. Combining NacNacMg(TMP) with pinacolone affords monomeric heteroleptic [Mg{(MeCN‐2,6‐iPr2C6H3)2CH}{OC(tBu)(Me)CH2C(=O)tBu}] with an aldolate constituting the second anion. Completing the set is dimeric [Mg{(MeCN‐2,6‐iPr2C6H3)2CH}{O(C=CH2)Ph}2], where the enolate derived from acetophenone bridges the magnesium centres.

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“…Given that the initial molar ratio of methanol to ethanol in the prereaction mixture is 14.4:1, it appears that the specific mixture of solid carboxylate formed is simply a function of the molar ratio of starting alcohols. Such solids are well-known as side products in Guerbet catalysis (even if they are not always reported) and form via the Cannizzaro or Tishchenko reaction from formaldehyde or acetaldehyde. , Any formate produced can be further dehydrogenated to sodium carbonate, which is detected by 13 C NMR spectroscopy. This dehydrogenation also produces hydrogen, which leads to a buildup of pressure within the autoclave over the course of the reaction. , It seems that this rhenium catalyst has a particular propensity to form such solids in comparison to analogous manganese or ruthenium catalysts.…”

Section: Resultsmentioning

confidence: 99%

“…Such solids are well-known as side products in Guerbet catalysis (even if they are not always reported) and form via the Cannizzaro or Tishchenko reaction from formaldehyde or acetaldehyde. 33,34 Any formate produced can be further dehydrogenated to sodium carbonate, which is detected by 13 C NMR spectroscopy. This dehydrogenation also produces hydrogen, which leads to a buildup of pressure within the autoclave over the course of the reaction.…”

Section: ■ Results and Discussionmentioning

confidence: 99%

Rhenium Complexes Bearing Tridentate and Bidentate Phosphinoamine Ligands in the Production of Biofuel Alcohols via the Guerbet Reaction

et al. 2021

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We report a variety of rhenium complexes supported by bidentate and tridentate phosphinoamine ligands and their use in the formation of the advanced biofuel isobutanol from methanol and ethanol. Rhenium pincer complexes 1−3 are effective catalysts for this process, with 2 giving isobutanol in 35% yields, with 97% selectivity in the liquid fraction, over 16 h with catalyst loadings as low as 0.07 mol %. However, these catalysts show poorer overall selectivity, with the formation of a significant amount of carboxylate salt solid byproduct also being observed. Production of the active catalyst 1d has been followed by 31 P NMR spectroscopy, and the importance of the presence of base and elevated temperatures to catalyst activation has been established. Complexes supported by diphosphine ligands are inactive for Guerbet chemistry; however, complexes supported by bidentate phosphinoamine ligands show greater selectivity for isobutanol formation over carboxylate salts. The novel complex 7 was able to produce isobutanol in 28% yield over 17 h. The importance of the N−H moiety to the catalytic performance has also been established, giving further weight to the hypothesis that these catalysts operate via a cooperative mechanism.

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Recent Advances and Prospects in the Tishchenko Reaction

Cited by 13 publications

References 88 publications

Synthesis and Characterization of N,N,C and N,N,O Tridentate β-Diketiminato Rare-Earth Metal Alkyl Complexes and Their Catalytic Performances on the Dimerization of Aldehydes or Terminal Alkynes

Synthesis and Characterization of N,N,C and N,N,O Tridentate β-Diketiminato Rare-Earth Metal Alkyl Complexes and Their Catalytic Performances on the Dimerization of Aldehydes or Terminal Alkynes

Crystallographic Characterisation of Organolithium and Organomagnesium Intermediates in Reactions of Aldehydes and Ketones

Rhenium Complexes Bearing Tridentate and Bidentate Phosphinoamine Ligands in the Production of Biofuel Alcohols via the Guerbet Reaction

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