ChemInform Abstract: Practical and Robust Method for Regio‐ and Stereoselective Preparation of (E)‐Ketene tert‐Butyl TMS Acetals and β‐Ketoester‐Derived tert‐Butyl (1Z,3E)‐1,3‐Bis(TMS)dienol Ethers.

Okabayashi, Tomohito; Iida, Akira; Takai, Kenta; Nawate, Yuuya; Misaki, Tomonori; Tanabe, Yoo

doi:10.1002/chin.200807051

Cited by 2 publications

(3 citation statements)

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“…46 Stereoselective Preparation of (E)-Ketene Trimethylsilyl Acetals (KSAs) in CPME. Okabayashi et al in 2007, investigated the synthesis of ketene silyl acetals (KSAs), 47 a highly demanding ester employed as a reactive precursor in various organic reactions such as Mukaiyama aldol and Michael reactions, Ireland−Claisen rearrangement, Diels− Alder reaction, etc. Following this, tert-butyl ester has been enolized with lithium diisopropylamide (LDA) at 0−5 °C followed by trapping with TMSCl in ether solvent (Scheme 18).…”

Section: ■ Introductionmentioning

confidence: 99%

“…42 The solvent screening effect concludes that the best result was obtained by CPME with regards to both yield (80%) and regioselectivity (>97:3), whereas the use of Et 2 O, THF, dioxane, and DME resulted in poor regioselectivity with the formation of undesirable C-silylation (B). 47 To be noted that the use of a bulky tert-butyl group also promotes stereoselectivity.…”

Section: ■ Introductionmentioning

confidence: 99%

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Unconventional Ethereal Solvents in Organic Chemistry: A Perspective on Applications of 2-Methyltetrahydrofuran, Cyclopentyl Methyl Ether, and 4-Methyltetrahydropyran

Bijoy

Agarwala

Roy

et al. 2021

Org. Process Res. Dev.

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Solvents are crucial platforms in organic synthesis. Thereby, the choice of a solvent is critical in order to develop sustainable eco-friendly synthetic methodologies. Hence, the present consensus is to employ environmentally friendly solvents which have broad applications in fine chemical syntheses, especially from the context of large-scale industrial preparations. In this review, we provide several examples for the utilization of 2-MeTHF, CPME, and 4-MeTHP in several organic reactions pertaining to organometallic-, organo-, and biocatalysis and highlight their potential use as benign alternatives to conventional ether solvents. These solvents have favorable physical and chemical characteristics, such as low toxicity and high chemical and thermal stabilities, which make them promising media for a large breadth of synthetic chemistry and triggers development of reactions with green chemistry protocols.

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Section: ■ Introductionmentioning

confidence: 99%

Section: ■ Introductionmentioning

confidence: 99%

Unconventional Ethereal Solvents in Organic Chemistry: A Perspective on Applications of 2-Methyltetrahydrofuran, Cyclopentyl Methyl Ether, and 4-Methyltetrahydropyran

Bijoy

Agarwala

Roy

et al. 2021

Org. Process Res. Dev.

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show abstract

“…The reactions were conducted under mild conditions, 0−5 °C, 2.5 h and produced both (E)-KSAs and 1,3bis(TMS)-KSAs, see Scheme 71. 359 α-Oxygen and α -nitrogensubstituted t-butyl esters were also shown to be compatible with this methodology. During solvent screening for reaction condition optimization, it was shown that other ethereal solvents such as diethyl ether, THF, 1,4-dioxane, and dimethoxyethane led to poor regioselectivity and C-silylation, whereas CPME by comparison outperformed all of these solvents.…”

Section: Amide Bond Formationmentioning

confidence: 90%

Replacement of Less-Preferred Dipolar Aprotic and Ethereal Solvents in Synthetic Organic Chemistry with More Sustainable Alternatives

et al. 2022

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Dipolar aprotic and ethereal solvents comprise just over 40% of all organic solvents utilized in synthetic organic, medicinal, and process chemistry. Unfortunately, many of the common “go-to” solvents are considered to be “less-preferable” for a number of environmental, health, and safety (EHS) reasons such as toxicity, mutagenicity, carcinogenicity, or for practical handling reasons such as flammability and volatility. Recent legislative changes have initiated the implementation of restrictions on the use of many of the commonly employed dipolar aprotic solvents such as dimethylformamide (DMF) and N -methyl-2-pyrrolidinone (NMP), and for ethers such as 1,4-dioxane. Thus, with growing legislative, EHS, and societal pressures, the need to identify and implement the use of alternative solvents that are greener, safer, and more sustainable has never been greater. Within this review, the ubiquitous nature of dipolar aprotic and ethereal solvents is discussed with respect to the physicochemical properties that have made them so appealing to synthetic chemists. An overview of the current legislative restrictions being imposed on the use of dipolar aprotic and ethereal solvents is discussed. A variety of alternative, safer, and more sustainable solvents that have garnered attention over the past decade are then examined, and case studies and examples where less-preferable solvents have been successfully replaced with a safer and more sustainable alternative are highlighted. Finally, a general overview and guidance for solvent selection and replacement are included in the Supporting Information of this review.

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ChemInform Abstract: Practical and Robust Method for Regio‐ and Stereoselective Preparation of (E)‐Ketene tert‐Butyl TMS Acetals and β‐Ketoester‐Derived tert‐Butyl (1Z,3E)‐1,3‐Bis(TMS)dienol Ethers.

Cited by 2 publications

References 1 publication

Unconventional Ethereal Solvents in Organic Chemistry: A Perspective on Applications of 2-Methyltetrahydrofuran, Cyclopentyl Methyl Ether, and 4-Methyltetrahydropyran

Unconventional Ethereal Solvents in Organic Chemistry: A Perspective on Applications of 2-Methyltetrahydrofuran, Cyclopentyl Methyl Ether, and 4-Methyltetrahydropyran

Replacement of Less-Preferred Dipolar Aprotic and Ethereal Solvents in Synthetic Organic Chemistry with More Sustainable Alternatives

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