A broadly applicable and practical oligomeric (salen)Co catalyst for enantioselective epoxide ring-opening reactions

White, David E.; Tadross, Pamela M.; Lü, Zhe; Jacobsen, Eric N.

doi:10.1016/j.tet.2014.03.043

Cited by 75 publications

(41 citation statements)

References 145 publications

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“…Jacobsen and his group described highly enhanced reactivity and enantioselectivity by employing cyclic multimeric cobalt‐salen complexes. While using their monomeric Co(OTs)‐complex at 4 °C, 80 % conversion could be reached after three days and the diol was isolated with 64 % ee; the oligomeric species allowed increasing both the activity (>99 % conversion after 11 h) and the selectivity (96 % ee) ,,. In our case, an adjustment of the reaction conditions was necessary to obtain a complete conversion into (1 R ,2 R )‐cyclohexane‐1,2‐diol.…”

Section: Resultsmentioning

confidence: 77%

Calix[8]arene as New Platform for Cobalt‐Salen Complexes Immobilization and Use in Hydrolytic Kinetic Resolution of Epoxides

et al. 2018

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Eight cobalt‐salen complexes have been covalently attached to a calix[8]arene platform through a flexible linker by a procedure employing Click chemistry. The corresponding well‐defined catalyst proved its efficiency in the hydrolytic kinetic resolution (HKR) of various epoxides through an operative bimetallic cooperative activation, demonstrating highly enhanced activity when compared to its monomeric analogue. As an insoluble complex, this multisite cobalt‐salen catalyst could be easily recovered and reused in successive catalytic runs. Products were isolated by a simple filtration with virtually no cobalt traces and without requiring a prior purification by flash chromatography.

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Section: Resultsmentioning

confidence: 77%

Calix[8]arene as New Platform for Cobalt‐Salen Complexes Immobilization and Use in Hydrolytic Kinetic Resolution of Epoxides

et al. 2018

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“…Such a process was pioneered by Jacobsen et al . by preparing a cyclic oligomeric Co(OTf)‐salen complex as practical catalyst for enantioselective epoxide ring‐opening reactions with different nucleophiles . The catalyst, which was synthetized from commercially available precursors, delivered higher activity and ee values than the related monomer, by favoring the necessary cooperativity due to the established bimetallic mechanism .…”

Section: Macrocyclic Salen Complexesmentioning

confidence: 99%

Chiral Salen Complexes for Asymmetric Heterogeneous Catalysis: Recent Examples for Recycling and Cooperativity

2019

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Chiral salen complexes are privileged and versatile catalysts used in a wide variety of enantioselective transformations. Researches for their use in multicatalysis, including cooperative as well as tandem processes, are more recent, but many reports already highlight the important effect of the salen ligand structure on reaction rates and/or selectivities. This review article thus outlines the literature covering last five years, on the current developments of chiral polymetallic salen complexes used in asymmetric heterogeneous catalysis; their preparation, their efficiency as catalysts in various reactions and their recyclability are highlighted according to the immobilization procedures involved for their heterogenization. These methods include grafting on organic or inorganic supports insuring easy recovery by simple filtration. Polymerization processes are also part of recent research, leading to high densities of catalytic sites to favor their cooperativity. Combination of salen complexes via non covalent interactions or their introduction on MOFs and COFs networks is currently in full expansion, with examples of highly functionalized and enantioenriched products issued from tandem catalysis.

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“…In 1990s, Jacobsen et al demonstrated the exceptional catalytic performance of Cr(III)-salen complexes in the kinetic resolution of racemic terminal monosubstituted and 2,2-disubstituted epoxides by TMSN 3 , which occurred with complete regioselectivity for the terminal position and very high stereoselectivity factors of up to 280 [107]. Later, these authors reported enhanced reactivity by using dimeric catalyst 124 in hydrolytic kinetic resolution of terminal epoxides (Scheme 50) [108]. A recent synthetic application of kinetic resolution using primary alcohols was illustrated by the same authors in the total synthesis of (+)-reserpine via intermediate enone 125 [109].…”

Section: Kinetic Resolutions Of Racemic Epoxides As Key Stepsmentioning

confidence: 99%

Applications of Chiral Three-membered Rings for Total Synthesis: A Review

Dalpozzo¹,

Lattanzi

Pellissier

2017

COC

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This review updates recent applications of asymmetric aziridination, azirination, thiirination, epoxidation, and cyclopropanation in the total synthesis of biologically active compounds, including natural products, using chiral substrates or chiral catalysts, covering the literature since 2000. The interest towards these synthetic methodologies of chiral three-membered rings has increased in the last decade, dictated either by the biological activities that display many naturally occurring products bearing a three-membered unit or by the ring strain of three-membered rings making them useful precursors of many more complex interesting molecules. Classic as well as modern protocols in asymmetric aziridinations, azirinations, epoxidations, thiirinations, and cyclopropanations have been widely applied as key steps of a number of syntheses of important products. Although the use of chiral substrates and auxiliaries is still highly employed particularly in asymmetric aziridination and cyclopropanation, the development of enantioselective catalytic methodologies has witnessed exponential growth during the last decade. The present review is subdivided into three parts, dealing successively with the use of chiral nitrogen-containing three-membered rings, chiral epoxides and thiiranes, and chiral cyclopropanes in total synthesis.

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A broadly applicable and practical oligomeric (salen)Co catalyst for enantioselective epoxide ring-opening reactions

Cited by 75 publications

References 145 publications

Calix[8]arene as New Platform for Cobalt‐Salen Complexes Immobilization and Use in Hydrolytic Kinetic Resolution of Epoxides

Calix[8]arene as New Platform for Cobalt‐Salen Complexes Immobilization and Use in Hydrolytic Kinetic Resolution of Epoxides

Chiral Salen Complexes for Asymmetric Heterogeneous Catalysis: Recent Examples for Recycling and Cooperativity

Applications of Chiral Three-membered Rings for Total Synthesis: A Review

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