SN2 reaction of 2-substituted 3-piperidinol mesylate with retention of configuration: application to the asymmetric synthesis of (2R,3S)-CP-99,994

Liu, Liangxian; Huang, Pei‐Qiang

doi:10.1016/j.tetasy.2006.12.009

Cited by 18 publications

(5 citation statements)

References 53 publications

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“…The use of neighboring-group participation to control stereochemistry has proven to be an effective strategy for a number of transformations. − Carbohydrate chemistry, in particular, has benefited from the application of anchimeric assistance in glycosylation reactions. , Sulfur-, , iodine-, , and acetoxy-substituted , glycosyl donors undergo highly trans-selective reactions, which have been postulated to involve nucleophilic ring-opening reactions (S N 2) of onium ion intermediates (Scheme ) . For example, Boons and co-workers recently demonstrated the utility of neighboring-group participation in their elegant method for the synthesis of α-glycosides .…”

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confidence: 99%

C-Glycosylation Reactions of Sulfur-Substituted Glycosyl Donors: Evidence against the Role of Neighboring-Group Participation

2008

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Nucleophilic substitution reactions of C-4 sulfur-substituted tetrahydropyran acetals revealed that neighboring-group participation does not control product formation. Spectroscopic evidence for the formation of an intermediate sulfonium ion is provided, as are data from nucleophilic substitution reactions demonstrating that products are formed from oxocarbenium ion intermediates. The selectivity was not sensitive to solvent or to which Lewis acid was employed. The identity of the heteroatom at the C-4 position also did not significantly impact diastereoselectivity. Consequently, neighboring-group participation was not responsible for the formation of either the major or the minor products. These studies implicate a Curtin-Hammett kinetic scenario in which the formation of a low-energy intermediate does not necessitate its involvement in the product-forming pathway.

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confidence: 99%

C-Glycosylation Reactions of Sulfur-Substituted Glycosyl Donors: Evidence against the Role of Neighboring-Group Participation

2008

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“…It is now important to also show that after successful hydration, the auxiliary sulfonamide can be removed from the amino alcohol. The cleavage of sulfonamides is in most cases carried out under reductive conditions, but none of the common reducing reagents worked for our system. , However, upon N -acylation, reductive cleavage with Mg was feasible, as documented for the transformation of 2ab . Thus, N -acetylation followed by O -benzoylation leading to 15 and subsequent treatment with magnesium in methanol under sonication afforded the N -benzoylated amino alcohol 16 in 70% overall yield and complete stereospecifity.…”

Section: Results and Discussionmentioning

confidence: 91%

Intramolecular Radical Oxygen-Transfer Reactions Using Nitroarenes

et al. 2023

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Intramolecular atom and group transfers are common steps in radical cascade reactions that have been utilized in various transformations. These types of radical translocations (group shifts) are reported for, but not limited to, alkenyl, alkynyl, aryl, cyano, chalcogenyl, and boryl groups. However, the intramolecular radical transfer of an oxygen atom is barely known. Herein, we disclose a radical transformation that allows intramolecular oxygen atom transfer to alkenes, utilizing the nitro functionality in nitroarenes as an oxygen donor. Reactions proceed via iron-catalyzed metal hydrogen atom transfer to alkenes with subsequent oxygenation resulting in alkene hydration. As compared to the intermolecular radical oxygenation, which is well investigated, the intramolecular variant offers advantages, particularly considering diastereoselective radical hydration of conformationally flexible alkenes. The aryl moiety connecting the reactive NO2-functionality to the alkene substrate can be cleaved after oxygen transfer, yielding products that derive from a formal diastereoselective intermolecular alkene hydration. On the other hand, the aniline entity resulting after oxygen transfer can be used for construction of nitrogen-containing heterocycles.

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“…51 The reaction is both stereospecific and regiospecific when the 2substituent is phenyl but not when it is methyl. The cis-stereoisomer is thought to be de formed in a direct S N 2 displacement of the mesylate group that competes with the formation of the aziridine ring intermediate.…”

Section: Aziridines and Other Small Ring Substitutionsmentioning

confidence: 99%

Nucleophilic Aliphatic Substitution

Westaway

2010

Organic Reaction Mechanisms · 2006

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SN2 reaction of 2-substituted 3-piperidinol mesylate with retention of configuration: application to the asymmetric synthesis of (2R,3S)-CP-99,994

Cited by 18 publications

References 53 publications

C-Glycosylation Reactions of Sulfur-Substituted Glycosyl Donors: Evidence against the Role of Neighboring-Group Participation

C-Glycosylation Reactions of Sulfur-Substituted Glycosyl Donors: Evidence against the Role of Neighboring-Group Participation

Intramolecular Radical Oxygen-Transfer Reactions Using Nitroarenes

Nucleophilic Aliphatic Substitution

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