Rate enhancement of the Meerwein-Ponndorf-Verley-Oppenauer reaction in the presence of proton acids

Kow, Ronald; Nygren, Robert; Rathke, Michael W.

doi:10.1021/jo00425a011

Cited by 29 publications

(19 citation statements)

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“…For instance aluminium tri-isopropoxide is commonly used in the polymer chemistry, e.g. the ring opening polymerisation of cyclic anhydrides [2], e-caprolactone [3] and lactides [4] as well as a catalyst of the Meerwein-Ponndorf-Verley reduction [5] and in the conversion of aldehydes into esters (Claisen-Tishchenko) [6]. We recently reported that this bulk aluminium alkoxide can be also used as a catalyst in the copolymerisation of cyclohexene oxide with carbon dioxide [7].…”

Section: Introductionmentioning

confidence: 99%

Synthesis, structural characterisation of new oligomeric alkyl aluminium (2,2′-methylene-p-chloro-bisphenoxides) and application as catalysts in polymerisation reactions involving cyclohexene oxide

Zevaco

Sypien

Janssen

et al. 2007

Journal of Organometallic Chemistry

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Section: Introductionmentioning

confidence: 99%

Synthesis, structural characterisation of new oligomeric alkyl aluminium (2,2′-methylene-p-chloro-bisphenoxides) and application as catalysts in polymerisation reactions involving cyclohexene oxide

Zevaco

Sypien

Janssen

et al. 2007

Journal of Organometallic Chemistry

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“…Since the alans are known to form stable dimers, 11,19 our model reaction describes the alan dimer formation first, then the ketone adduct formation. The ketone-alan adducts are assumed to be formed with monomeric alans which are dissociated from the alan dimers.…”

Section: Resultsmentioning

confidence: 99%

“…Aluminum alkoxides (Al(OR) 3 ) are known to form aggregates and the carbonyl substrates have to be inserted to the aggregate to form complexes with Al in the reduction process. 19 In the same sense, DIBAL(X) may form dimers or higher aggregates with bridging X. And one can consider a role of electrophilic aluminum of DIBAL(X), which forms either dimers or adducts with carbonyl compounds.…”

Section: 4mentioning

confidence: 99%

Relative Reactivity of Various Al-substituted-dialkylalans in Reduction of Carbonyl Compounds: A Theoretical Study on Substituent Effect

Nahm

Soon²

2013

Bulletin of the Korean Chemical Society

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Relative reactivity of various Al-substituted dialkylalans (AlR 2 (X)) in reduction of acetone has been studied with density functional theory and MP2 method. Formation of the alan dimers and the alan-acetone adduct, and the transition state for the Meerwein-Ponndorf-Verley (MPV) type reduction of the adduct were calculated to figure out the energy profile. Formation of dimeric alans is highly exothermic. Both the relative free energies for acetone-alan adduct formation and the TS barriers for the MPV type reduction with respect to alan dimers and acetone were calculated and they show the same trend. Based on these energetic data, relative reactivity of alans is expected to be; AlR 2 (Cl) > AlR 2 (OTf) > AlR 2 (O 2 CCF 3 ) > AlR 2 (F) > AlR 2 (OMs) > AlR 2 (OAc) > AlR 2 (OMe) > AlR 2 (NMe 2 ). The energy profile is relatively well correlated with the experimental order of the reactivity of Al-substituted dialkylalans. It is noted that the substituents of alans have initial effects on the relative free energies for the carbonyl-adduct formation. Therefore, an AlR 2 (X) which forms a more stable carbonyl-adduct is more reactive in carbonyl reduction.

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“…In general, electronegativity and resonance effect of the substituent Y, and the interaction between carbonyl oxygen electrons and Lewis acids exert powerful effect to the reactivity. 8 Since DIBAL(X) is known to form a stable dimer and the dimer is not reactive in reduction, 9 the carbonyl-alan adduct formation could be an important factor in the reduction. Another factor is a TS barrier of the MPV-type hydride transfer of the adduct.…”

Section: Dibal(x) Which Is Easily Derived From Dibalh (Diisobutylalumentioning

confidence: 99%

MPV-Reduction of C=O bond with Al-substituted-dialkylalan; A Theoretical Study on Relative Reactivity of Various Carbonyl Substrates

Nahm

2014

Bulletin of the Korean Chemical Society

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Relative reactivity of various carbonyl and acid derivatives in MPV-type (Meerwein-Ponndorf-Verley) reduction with an DIBAL(F) model has been studied via DFT and MP2 methods. Free energies of initial adduct formation (G add ) of DIBAL(F) model and carbonyls are in the order of amide < ester < aldehyde < ketone < acid chloride; in the alan-amide adduct, the developed positive charge at carbonyl carbon is expected to be stabilized by amide resonance, but in the acid chloride adduct it is destabilized by inductive effect of chloride. However the TS barrier energies (G TS ) for the MPV-type hydride reduction of the carbonyl adducts are in the order of aldehyde < ketone < acid chloride << ester < amide; presumably decreasing order of electrophilicity of carbonyl carbon at adducts, which is well correlated with experimental data. It is noted that the relative reactivity of carbonyl derivatives in MPV-type reduction with DIBAL(X) is not governed by the alan-adduct formation energies, but follows the order of electrophilicity of carbonyl carbon of transition states.

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Rate enhancement of the Meerwein-Ponndorf-Verley-Oppenauer reaction in the presence of proton acids

Cited by 29 publications

References 0 publications

Synthesis, structural characterisation of new oligomeric alkyl aluminium (2,2′-methylene-p-chloro-bisphenoxides) and application as catalysts in polymerisation reactions involving cyclohexene oxide

Synthesis, structural characterisation of new oligomeric alkyl aluminium (2,2′-methylene-p-chloro-bisphenoxides) and application as catalysts in polymerisation reactions involving cyclohexene oxide

Relative Reactivity of Various Al-substituted-dialkylalans in Reduction of Carbonyl Compounds: A Theoretical Study on Substituent Effect

MPV-Reduction of C=O bond with Al-substituted-dialkylalan; A Theoretical Study on Relative Reactivity of Various Carbonyl Substrates

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