Ground and excited state 1,4-addition reactions of some carbohydrate enones

Fraser‐Reid, Bert; Holder, N. L.; Yunker, Mark B.

doi:10.1039/c39720001286

Cited by 38 publications

(14 citation statements)

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“…Electrophilic carbon radicals similarly undergo addition to 4/,5'-unsaturated uracilnucleotides [46]. Fraser-Reid [47] has prepared C-2-and C-4-branched sugars by the photochemically induced addition of methanol to the endocyclic enone acceptors 56 and 57, respectively. The use of endocylic enone levoglucosenone 29 as a suitable acceptor for the preparation of C-disaccharides [34] has been discussed.…”

Section: Synthesis Of Branched-chain Sugarsmentioning

confidence: 99%

Radicals in Carbohydrate Chemistry

Pearce¹,

Mallet²,

Sînaÿ³

2001

Radicals in Organic Synthesis

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Radical methods are of central importance in organic synthesis [ 11. These reactions are performed under mild and neutral conditions, which usually avoids competing ionic side reactions. Carbon-centered radicals are compatible with a range of functional groups (e.g. aliphatic alcohols, amines, ketones, esters) and also show high chemoselectivity under carefully controlled reaction conditions. Furthermore, reactions involving loss of stereochemistry at the non-radical center are not problematic, and hence radical methods are emerging as a powerful synthetic tool in the field of carbohydrate chemistry.In this article we provide a broad overview of the application of radical methods in carbohydrate chemistry, including typical examples classified by the type of bond formed. The factors controlling the stereoselectivity of inter-and intramolecular C-C bond formation are now well understood and have been exploited in the synthesis of C-glycosides [2]. Intramolecular C-C bond formation using carbohydratebased chiral templates also provides a powerful route to branched-chain sugars [ 3 ] and carbocycles [4]. Finally, we include synthetically useful processes involving key carbon-heteroatom and C-H bond formation. Intermolecular Carbon-Carbon Bond Formation Synthesis of C-GlycosidesA powerful strategy for the formation of C-glycosides is the intermolecular addition of an anomeric radical to n-systems [2]. Anomeric pyranosyl radicals are readily generated by a variety of standard methods and are nucleophilic in character because of interaction of the SOMO with the non-bonding electron pair of the adjacent ring oxygen. Anomeric radicals therefore undergo addition to n-systems when the high-lying SOMO can interact with a low-lying LUMO as in electron-deficient Radicals in Organic Synthesis Edited

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Section: Synthesis Of Branched-chain Sugarsmentioning

confidence: 99%

Radicals in Carbohydrate Chemistry

Pearce¹,

Mallet²,

Sînaÿ³

2001

Radicals in Organic Synthesis

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“…The photoinduced addition of alcohols to -enones was not a popular reaction in 1972, although it dated back to 1957 when, in connection with a synthesis of terebic acid, Schenck and co-workers added isopropanol to maleic acid [65]. We found this process to be a promising method for carbon-carbon bond formation in carbohydrate chemistry, and also found that reaction with substrate 74 proceeded with complete regio-and stereoselectivity [66,67,68] (Scheme 20a-e). This methodology proved its flexibility with photoinduced addition of bifunctional alcohols (Scheme 20f), acetals [69] (Scheme 20g) and aldehydes [70,71] (Scheme 20h).…”

Section: Photochemically Induced Addition To Hex-2-enopyranosid-4-ulosesmentioning

confidence: 85%

Unsaturated Sugars: A Rich Platform for Methodological and Synthetic Studies

Fraser‐Reid¹,

López²

2009

COC

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“…Electron-transfer reactions between amines and excited-state ketones have been extensively studied. [67,68] The first report employing AQs as photosensitizers was described by Das and coworkers for the formation of CÀ C bonds between α,βunsaturated nitriles or esters and amines via PET processes. [69] The addition of α-aminoalkyl groups to methyl methacrylate (76) and subsequent 1,5-hydrogen abstraction gave polyaddition product 77 (Scheme 19) .…”

Section: Pyrrolizidones and Spirolactam Derivativesmentioning

confidence: 99%

“…Electron‐transfer reactions between amines and excited‐state ketones have been extensively studied . The first report employing AQs as photosensitizers was described by Das and coworkers for the formation of C−C bonds between α,β‐unsaturated nitriles or esters and amines via PET processes .…”

Section: Applications Of Aqs In Organic Synthesismentioning

confidence: 99%

Anthraquinones: Versatile Organic Photocatalysts

et al. 2020

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Anthraquinones (AQs) constitute the largest group of natural pigments, are commonly found in dyes, and are widely used in the textile industry due their photostability. They combine high absorptivity in the visible region with high excited‐state reduction potentials, making them effective acceptors of electrons and hydrogen atoms. AQs can be employed as organic catalysts in photooxidation reactions as well to produce reactive oxygen species (ROS). All these methods feature green chemistry aspects such as avoiding heavy metals, reducing waste, using inexpensive reagents, employing environmentally low‐impact solvents, and oxidizing with O2. This review covers the application of AQs in photoredox catalysis.

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Ground and excited state 1,4-addition reactions of some carbohydrate enones

Cited by 38 publications

References 0 publications

Radicals in Carbohydrate Chemistry

Radicals in Carbohydrate Chemistry

Unsaturated Sugars: A Rich Platform for Methodological and Synthetic Studies

Anthraquinones: Versatile Organic Photocatalysts

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