Participation of Alkoxy Groups in Reactions of Acetals: Violation of the Reactivity/Selectivity Principle in a Curtin–Hammett Kinetic Scenario

Garcia, Angie; Sanzone, Jillian R.; Woerpel, K. A.

doi:10.1002/ange.201503525

Cited by 5 publications

(3 citation statements)

References 35 publications

(48 reference statements)

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“…The participation by an alkoxy group can also lead to control of stereoselectivity in acetal substitution reactions. 116 The selectivities in many cases were high, and depended upon the reactivity of the nucleophile (Scheme 56 ). The trend in selectivity also corresponds to the trend in rate acceleration: acetals that hydrolyzed more rapidly reacted with higher stereoselectivity (Schemes 54 and 56).…”

Section: Neighboring-group Participation Is Not As Simple As It Seemsmentioning

confidence: 99%

Acetal Substitution Reactions: Stereoelectronic Effects, Conformational Analysis, Reactivity vs Selectivity, and Neighboring-Group Participation

Woerpel,

Chun,

Luu

2024

Synlett

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Acetal substitution reactions can proceed by a number of mechanisms, but oxocarbenium ion intermediates are involved in many of these reactions. Our research has focused on understanding the conformational preferences, structures, and reactions of these intermediates. This account summarizes our observations that electrostatic effects play a significant role in defining the preferred conformations, and that torsional effects determine how those intermediates react. Neighboring-group effects are not as straightforward as they might seem, considering that oxocarbenium ion intermediates are in equilibrium with structures that involve stabilization by a nearby substituent.1 Introduction2 Unexpected Stereoselectivities3 Determining Conformational Preferences of Oxocarbenium Ions4 Structures of Carbocations by NMR Spectroscopy and X-ray Crystallography5 Stereoelectronic Models for Reactions Involving Other Oxocarbenium Ions6 Stereoselectivity and Reactivity: When They Correlate, When They Do Not7 Neighboring–Group Participation Is Not as Simple as It Seems8 What Is True for Carbocations Is True for Carbonyl Compounds9 Stereoelectronic and Torsional Effects in Reactions of Enolates10 Summary of Expected Selectivities for Reactions of Cyclic Acetals11 Conclusion

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Section: Neighboring-group Participation Is Not As Simple As It Seemsmentioning

confidence: 99%

Acetal Substitution Reactions: Stereoelectronic Effects, Conformational Analysis, Reactivity vs Selectivity, and Neighboring-Group Participation

Woerpel,

Chun,

Luu

2024

Synlett

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“…In addition, over the recent years there has been a noticeable shift in focus of the mechanistic glycosylation chemistry field toward studying stereoelectronics and conformation of the starting material and key reaction intermediates. 74,75,77,79,80,82,84,91,100,172,223,277–290 While the stereoelectronic and conformational effects on reactivity have been studied extensively, the impact of these effects on stereoselectivity remains elusive. Although some model studies helped to establish general trends, 75,82,277–280,290,291 practical application of the conformational factors to stereocontrol of glycosylation is still limited.…”

Section: Traditional Manual Synthesis Of Oligosaccharidesmentioning

confidence: 99%

“…74,75,77,79,80,82,84,91,100,172,223,277−290 While the stereoelectronic and conformational effects on reactivity have been studied extensively, the impact of these effects on stereoselectivity remains elusive. Although some model studies helped to establish general trends, 75,82,[277][278][279][280]290,291 practical application of the conformational factors to stereocontrol of glycosylation is still limited. Reagent-or additive-controlled glycosylations and reactions with reagent-dependent switchable selectivity are becoming active areas of research.…”

Section: Chemical Reviewsmentioning

confidence: 99%

Automated Chemical Oligosaccharide Synthesis: Novel Approach to Traditional Challenges

et al. 2018

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Advances in carbohydrate chemistry have certainly made common oligosaccharides much more accessible. However, many current methods still rely heavily upon specialized knowledge of carbohydrate chemistry. The application of automated technologies to chemical and life science applications such as genomics and proteomics represents a vibrant field. These automated technologies also present opportunities for their application to organic synthesis, including that of the synthesis of oligosaccharides. However, application of automated methods to the synthesis of carbohydrates is an underdeveloped area as compared to other classes of biomolecules. The overarching goal of this review article is to present the advances that have been made at the interface of carbohydrate chemistry and automated technology.

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Bromine‐Promoted Glycosidation of Conformationally Superarmed Thioglycosides

Panza

Civera

Yasomanee

et al. 2019

Chemistry A European J

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Presented herein is a study of the conformation and reactivity of highly reactive thioglycoside donors. The structural studies have been conducted using NMR spectroscopy and computational methods. The reactivity of these donors has been investigated in bromine‐promoted glycosylations of aliphatic and sugar alcohols. Swift reaction times, high yields, and respectable 1,2‐cis stereoselectivity were observed in a majority of these glycosylations.

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Participation of Alkoxy Groups in Reactions of Acetals: Violation of the Reactivity/Selectivity Principle in a Curtin–Hammett Kinetic Scenario

Cited by 5 publications

References 35 publications

Acetal Substitution Reactions: Stereoelectronic Effects, Conformational Analysis, Reactivity vs Selectivity, and Neighboring-Group Participation

Acetal Substitution Reactions: Stereoelectronic Effects, Conformational Analysis, Reactivity vs Selectivity, and Neighboring-Group Participation

Automated Chemical Oligosaccharide Synthesis: Novel Approach to Traditional Challenges

Bromine‐Promoted Glycosidation of Conformationally Superarmed Thioglycosides

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