Hydrophobic amplification of noncovalent organocatalysis

Kleiner, Christian M.; Schreiner, Peter R.

doi:10.1039/b605850g

Cited by 149 publications

(75 citation statements)

References 31 publications

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“…Avery similar and meanwhile accepted idea is to direct organic synthesis through hydrophobic interactions [168] by carrying out reactions in water. [169] In such situations,t ransition states are favored in which the hydrophobic interactions are maximized.…”

Section: Dispersion Effects On Chemical Reactivitymentioning

confidence: 99%

London Dispersion in Molecular Chemistry—Reconsidering Steric Effects

2015

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London dispersion, which constitutes the attractive part of the famous van der Waals potential, has long been underappreciated in molecular chemistry as an important element of structural stability, and thus affects chemical reactivity and catalysis. This negligence is due to the common notion that dispersion is weak, which is only true for one pair of interacting atoms. For increasingly larger structures, the overall dispersion contribution grows rapidly and can amount to tens of kcal mol(-1) . This Review collects and emphasizes the importance of inter- and intramolecular dispersion for molecules consisting mostly of first row atoms. The synergy of experiment and theory has now reached a stage where dispersion effects can be examined in fine detail. This forces us to reconsider our perception of steric hindrance and stereoelectronic effects. The quantitation of dispersion energy donors will improve our ability to design sophisticated molecular structures and much better catalysts.

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Section: Dispersion Effects On Chemical Reactivitymentioning

confidence: 99%

London Dispersion in Molecular Chemistry—Reconsidering Steric Effects

2015

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“…85 The catalyst was designed to mimic the active site components of the enzyme epoxide hydrolase. Comparison of the reaction in dichloromethane and in water showed a prominent effect of the latter on the yield of the opening reaction.…”

Section: On Water Reactionsmentioning

confidence: 99%

Organic Synthesis “On Water”

2009

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“…[32] Thus, two different N,N'-disubstituted urea compounds (10 and 11) were added to the reaction mixture in the presence of the monomeric catalyst 2·OTs (Table 3). Both urea additives decreased the reaction rate in the HKR of rac-epichlorohydrin.…”

Section: Hydrolytic Kinetic Resolutionmentioning

confidence: 99%

Self‐Assembly Approach toward Chiral Bimetallic Catalysts: Bis‐Urea‐Functionalized (Salen)Cobalt Complexes for the Hydrolytic Kinetic Resolution of Epoxides

Park

Lang

Abboud

et al. 2011

Chemistry A European J

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A series of novel bis-urea-functionalized (salen)Co complexes has been developed. The complexes were designed to form self-assembled structures in solution through intermolecular urea-urea hydrogen-bonding interactions. These bis-urea (salen)Co catalysts resulted in rate acceleration (up to 13 times) in the hydrolytic kinetic resolution (HKR) of rac-epichlorohydrin in THF by facilitating cooperative activation, compared to the monomeric catalyst. In addition, one of the bis-urea (salen)Co(III) catalyst efficiently resolves various terminal epoxides even under solvent-free conditions by requiring much shorter reaction time at low catalyst loading (0.03-0.05 mol %). A series of kinetic/mechanistic studies demonstrated that the self-association of two (salen)Co units through urea-urea hydrogen bonds was responsible for the observed rate acceleration. The self-assembly study with the bis-urea (salen)Co by FTIR spectroscopy and with the corresponding (salen)Ni complex by (1)H NMR spectroscopy showed that intermolecular hydrogen-bonding interactions exist between the bis-urea scaffolds in THF. This result demonstrates that self-assembly approach by using non-covalent interactions can be an alternative and useful strategy toward the efficient HKR catalysis.

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Hydrophobic amplification of noncovalent organocatalysis

Abstract: The effects of hydrogen-bonding organocatalysts and water for the acceleration of epoxide openings with a variety of nucleophiles are additive and lead to excellent yields of the catalyzed reactions in water.

Cited by 149 publications

References 31 publications

London Dispersion in Molecular Chemistry—Reconsidering Steric Effects

London Dispersion in Molecular Chemistry—Reconsidering Steric Effects

Organic Synthesis “On Water”

Self‐Assembly Approach toward Chiral Bimetallic Catalysts: Bis‐Urea‐Functionalized (Salen)Cobalt Complexes for the Hydrolytic Kinetic Resolution of Epoxides

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