- Micellar Catalysis for Sustainable Hydroformylation
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It is here reported a fully sustainable and generally applicable protocol for the regioselective hydroformylation of terminal alkenes, using cheap commercially available catalysts and ligands, in mild reaction conditions (70 °C, 9 bar, 40 min). The process can take advantages from both micellar catalysis and microwave irradiation to obtain the linear aldehydes as the major or sole regioisomers in good to high yields. The substrate scope is largely explored as well as the application of hydroformylation in tandem with intramolecular hemiacetalization thus demonstrating the compatibility with a broad variety of functional groups. The reaction is efficient even in large scale and the catalyst and micellar water phase can be reused at least 5 times without any impact in reaction yields. The efficiency and sustainability of this protocol is strictly related to the in situ transformation of the aldehyde into the corresponding Bertagnini's salt that precipitates in the reaction mixture avoiding organic solvent mediated purification steps to obtain the final aldehydes as pure compounds.
- Calamante, Massimo,Dei, Filippo,Maramai, Samuele,Migliorini, Francesca,Petricci, Elena
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p. 2794 - 2806
(2021/05/03)
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- Binuclear Pd(I)-Pd(I) Catalysis Assisted by Iodide Ligands for Selective Hydroformylation of Alkenes and Alkynes
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Since its discovery in 1938, hydroformylation has been thoroughly investigated and broadly applied in industry (>107 metric ton yearly). However, the ability to precisely control its regioselectivity with well-established Rh- or Co-catalysts has thus far proven elusive, thereby limiting access to many synthetically valuable aldehydes. Pd-catalysts represent an appealing alternative, yet their use remains sparse due to undesired side-processes. Here, we report a highly selective and exceptionally active catalyst system that is driven by a novel activation strategy and features a unique Pd(I)-Pd(I) mechanism, involving an iodide-assisted binuclear step to release the product. This method enables β-selective hydroformylation of a large range of alkenes and alkynes, including sensitive starting materials. Its utility is demonstrated in the synthesis of antiobesity drug Rimonabant and anti-HIV agent PNU-32945. In a broader context, the new mechanistic understanding enables the development of other carbonylation reactions of high importance to chemical industry.
- Zhang, Yang,Torker, Sebastian,Sigrist, Michel,Bregovi?, Nikola,Dydio, Pawe?
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supporting information
p. 18251 - 18265
(2020/11/02)
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- Rhodium/Phosphine catalysed selective hydroformylation of biorenewable olefins
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This work reports rhodium catalyzed selective hydroformylation of natural olefins like eugenol, estragole, anethole, prenol and isoprenol using biphenyl based Buchwald phosphine ligands (S-Phos (L1), t-Bu XPhos (L2), Ru-Phos (L3), Johnphos (L4) and DavePhos (L5). Ru-Phos (L3) ligand exhibited high impact on the hydroformylation of eugenol providing high selectivity (90%) of linear aldehyde as major product. In addition, internal natural olefins like anethole and prenol provided moderate to high selectivity (65% and 85% respectively) of branched aldehydes as a major products. The various reaction parameters such as influence of ligands, P/Rh ratio, syngas pressure, temperature, time and solvents have been studied. A high activity and selectivity gained on the way to the linear aldehydes it may be due to the bulky, steric cyclohexyl and isopropoxy groups present in L3 phosphine ligand. Moreover, this catalytic system was smoothly converting natural olefins into corresponding linear and branched aldehydes with higher selectivity under the mild reaction conditions.
- Jagtap, Samadhan A.,Bhanage, Bhalchandra M.
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- Rhodium-catalyzed one-pot hydroformylation-cyclization of allylbenzene derivatives: Simple and efficient route to 5,6-dihydronaphthalenes
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The one-pot hydroformylation-cyclization of allylbenzene derivatives by the catalyst system Rh(CO)2acac/ultranox626/CO/H2/CH2Cl2 led chemoselectively to 5,6-dihydronaphthalene derivatives 5a-d in good yields. The addition of a catalytic amount of H3PO4 enhanced in situ the cyclization process via the nucleophilic attack on the carbonyl group of the linear aldehyde, and finally the elimination of alcohol. The type of substitution on phenyl group of the allylbenzene is of great importance in enhancing the cyclization process.
- Alhaffar, Mouheddin,Suleiman, Rami,Ali, Bassam El
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experimental part
p. 778 - 782
(2010/07/06)
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- Thermoregulated microemulsions by cyclodextrin sequestration: A new approach to efficient catalyst recovery
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The use of imidazolium surfactants with cyclodextrins (CDs) as a control element in the thermoregulated olefin hydroformylation was reported. The 1-alkyl-3-methylimidazolium salts was used as surfactants for the rhodium-catalyzed hydroformylation reaction
- Leclercq, Loic,Lacour, Matthieu,Sanon, Samantha H.,Schmitzer, Andreea R.
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supporting information; experimental part
p. 6327 - 6331
(2010/03/03)
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- Bidentate ligands by self-assembly through hydrogen bonding: A general room temperature/ambient pressure regioselective hydroformylation of terminal alkenes
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The 6-DPPon (1)/rhodium catalyst allows for the first time a room temperature/ambient pressure regioselective hydroformylation of terminal alkenes with low catalyst loadings in good activity. The generality of this catalyst under these conditions was demonstrated for a wide range of structurally diverse alkenes equipped with many important functional groups. Thus, this practical and highly selective hydroformylation protocol, which omits the need for special pressure equipment, should find wide application in organic synthesis.
- Seiche, Wolfgang,Schuschkowski, Alexander,Breit, Bernhard
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p. 1488 - 1494
(2007/10/03)
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