Asymmetric Organocatalytic Efficiency of Synthesized Chiral β-Amino Alcohols in Ring-Opening of Glycidol with Phenols

Aral, Tarık; Karakaplan, Mehmet; Hoşgören, Halil

doi:10.1007/s10562-012-0814-4

Cited by 16 publications

(9 citation statements)

References 40 publications

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“…By examining various β-amino primary and secondary alcohols as the organocatalyst, pyridine derived secondary C 2 -symmetric βamino alcohols were found to exhibit better reactivities and stereoselectivities. 86 However, the reaction was applied to a limited number of substrates.…”

Section: Stereoselective Ring Opening Of Epoxy Alcoholsmentioning

confidence: 99%

“…A chiral β-amino alcohol-based organocatalyst enables the desired epoxide ring opening with phenols in moderate to high yields and enantioselectivities (Scheme ). By examining various β-amino primary and secondary alcohols as the organocatalyst, pyridine derived secondary C 2 -symmetric β-amino alcohols were found to exhibit better reactivities and stereoselectivities . However, the reaction was applied to a limited number of substrates.…”

Section: Hydroxy-directed Asymmetric Reactionsmentioning

confidence: 99%

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Substrate Directed Asymmetric Reactions

2018

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Historically, reagent controlled reactions (mechanism controlled reactions) have played a significant role in the asymmetric synthesis of complex structures. In contrast, today's asymmetric synthesis is greatly dependent on substrate directed approaches. In this approach, a polar functional group, namely, a "directing group", in the vicinity of the reactive site inside the substrate has been documented to preassociate with the chiral catalyst, which exerts stereodirecting influence by directing the reacting partner toward one of the enantiotopic faces of the reaction center. Those reactions usually proceed through exceptionally ordered transition states and result in extraordinary levels of stereoselection. Within the last four decades, the substrate directed approach has become an indispensible tool for the preparation of complex chiral frameworks starting directly from relatively simple achiral substrate molecules via asymmetric induction or various resolution techniques or both. Likewise, the substrate directed approach has been applied to functionalize enantiopure substrates bearing pre-exisiting stereocenters into complex structures as a single diastereomer. A classical example is Sharpless asymmetric epoxidation of allylic alcohols in which the free hydroxy function acts as an active anchor to a dimeric Ti-catalyst that controls the stereochemical outcome of the epoxidation process by transferring the oxidant enantioselectively. The principal aim of the present review is to give a general overview of substrate directed asymmetric transformations, a topic that has not yet been documented in the form of a concise review of recently developed approaches. Due to the large number of related applications, only recent advances that have been documented within the last two decades have been reviewed. Furthermore, in the current review, we have mainly highlighted asymmetric reactions that are controlled by abundant and frequently used directing groups such as hydroxy, amide, and sulfonamide groups. In addition, selected examples of a few important substrate-directed chemo-, regio-, and diastereoselective reactions have also been included in this review.

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Section: Stereoselective Ring Opening Of Epoxy Alcoholsmentioning

confidence: 99%

Section: Hydroxy-directed Asymmetric Reactionsmentioning

confidence: 99%

Substrate Directed Asymmetric Reactions

2018

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“…

AF e III -triflate complex, bearing ab is-thioether-di-phenolate [OSSO]-type ligand,w as discovered to promote the ring-opening of glycidol with alcohols under mild reaction conditions (0.05 mol %c atalysta nd 80 8C). [8][9][10][11] Among oxiranes,g lycidol (GLY) has attracted much attention, not only because it can act as cornerstone for the synthesis of more complexm olecules, but also because the presence of ah ydroxy group profoundly influences its reactivity. This synthetic approacha llows the conversion of ag lycerol-derived platform molecule (i.e.,g lycidol)t oh igh-value-added products by using an Earth-crust abundantmetal-based catalyst.

The regioselective ring-opening of epoxides hasb een intensively investigated during the last two decades.

…”

mentioning

confidence: 99%

Regioselective Ring‐Opening of Glycidol to Monoalkyl Glyceryl Ethers Promoted by an [OSSO]‐Fe^III Triflate Complex

et al. 2019

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AF e III -triflate complex, bearing ab is-thioether-di-phenolate [OSSO]-type ligand,w as discovered to promote the ring-opening of glycidol with alcohols under mild reaction conditions (0.05 mol %c atalysta nd 80 8C). The reactionp roceeded with high activity (initial turnover frequency of 1680 h À1 for EtOH) and selectivity( > 95 %) toward the formation of twelve monoalkyl glyceryl ethers (MAGEs) in ar egioselective fashion (84-96 %y ield of the non-symmetric regioisomer). This synthetic approacha llows the conversion of ag lycerol-derived platform molecule (i.e.,g lycidol)t oh igh-value-added products by using an Earth-crust abundantmetal-based catalyst.The regioselective ring-opening of epoxides hasb een intensively investigated during the last two decades. [1][2][3][4][5][6][7] In particular, since the discoveryo fm anyu seful synthetic strategies that have given access to aw ide variety of chiral epoxides, this reaction has becomeani mportant entry in the toolbox of organic synthesis for obtaining enantiopure molecules. [8][9][10][11] Among oxiranes,g lycidol (GLY) has attracted much attention, not only because it can act as cornerstone for the synthesis of more complexm olecules, but also because the presence of ah ydroxy group profoundly influences its reactivity. [12][13][14] We have recentlys hown that GLYc an be conveniently obtained as a value-added product from biobasedepichlorohydrin (ECH) productionp lants (EPICEROL process, Solvay), [15] thereby enhancing the environmental sustainability of the entireE CH chain as well as interest towards GLYc onversiont ov aluable chemicals such as polymers, [16] drugs, [17] diols, [18][19][20] solketal, [21,22] and organic carbonates. [12,13] Among the possible products that can be obtained by nucleophilic ring-opening of GLY, monoalkyl glyceryl ethers (MAGEs) are ar elevant class of molecules, not only because they represent one of the most successful examples of glycerol valorizationb ut also because they find application in many significant industrial areas. [23] Unfortunately,t he direct synthesis of MAGEs form GLYi sa ffectedb ym any drawbacks (high temperature, low chemo-and regioselectivity,h igh catalystl oading) rendering thiss ynthetic strategy inconvenient for industrial implementation. [24,25] Nevertheless, such as ynthesis was recently accomplished both under basic conditions [26] and in the presence of acidic heterogeneous (i.e.,A mberlyst IRA-400a nd Nafion NR50) [27,28] and homogenous( metal triflates) [29,30] catalytic systems. [31] Since the first efforts, both synthetic strategies have been optimized towards milder reaction conditions and larger substrate scope (Scheme 1).Pires and co-workers reported the selectivep reparation of MAGEsf rom GLYa nd alcohols in the presence of 20 mol % KOH as basic homogeneous catalyst with good yields. [26] Herein,g lycidol was added dropwise to the reaction medium to improvet he selectivity to MAGEs by inhibiting oligomerization side reactions.H owever,t he regioselectivity strongly dependedo nt he alcoholics ...

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“…The authors proposed that the catalyst activated both the glycidol ring and phenol by hydrogen bond formation. 44…”

Section: Miscellaneousmentioning

confidence: 99%

Organocatalysis in synthesis and reactions of epoxides and aziridines

2013

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Asymmetric Organocatalytic Efficiency of Synthesized Chiral β-Amino Alcohols in Ring-Opening of Glycidol with Phenols

Cited by 16 publications

References 40 publications

Substrate Directed Asymmetric Reactions

Substrate Directed Asymmetric Reactions

Regioselective Ring‐Opening of Glycidol to Monoalkyl Glyceryl Ethers Promoted by an [OSSO]‐Fe^III Triflate Complex

Organocatalysis in synthesis and reactions of epoxides and aziridines

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Asymmetric Organocatalytic Efficiency of Synthesized Chiral β-Amino Alcohols in Ring-Opening of Glycidol with Phenols

Cited by 16 publications

References 40 publications

Substrate Directed Asymmetric Reactions

Substrate Directed Asymmetric Reactions

Regioselective Ring‐Opening of Glycidol to Monoalkyl Glyceryl Ethers Promoted by an [OSSO]‐FeIII Triflate Complex

Organocatalysis in synthesis and reactions of epoxides and aziridines

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Regioselective Ring‐Opening of Glycidol to Monoalkyl Glyceryl Ethers Promoted by an [OSSO]‐Fe^III Triflate Complex