Intramolecular Cine Substitution on Carbohydrates
The reactions of C-radical systems with a -ester group are considered of great interest since migration resulting products could be obtained. These processes involve a cation-radical intermediate which could be trapped inter- or intramolecularly by a nucleophile in an ipso or cine way. In this sense, intramolecular processes offer the possibility to synthesize interesting cyclic products from acyclic structures. However, to this moment only a few examples of intramolecular cine substitution applied to cyclic starting materials has been reported, and no studies of the probable influence of the stereoelectronic nature of the leaving group (LG) over the mechanism, have been developed. Herein, we describe an intramolecular cine substitution on conformationally restricted carbohydrate systems to show some light over the stereoelectronic requirements of the LG to promote the cine mechanism against others. We have studied the evolution of 1-glycosyl and 4-glycosyl radicals, with proper adyacent LGs, resulting from a 1,5-Hydrogen Atom Transfer (HAT) process to obtain spiroacetalic and dioxabicyclic compounds respectively.
Main Authors: | , , , , |
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Other Authors: | |
Format: | Comunicación oral presentada en 29th International Carbohydrate Symposium biblioteca |
Language: | English |
Published: |
2018-07-15
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Subjects: | carbohydrate, |
Online Access: | http://hdl.handle.net/10261/342606 |
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Summary: | The reactions of C-radical systems with a -ester group are considered of great interest since
migration resulting products could be obtained. These processes involve a cation-radical intermediate
which could be trapped inter- or intramolecularly by a nucleophile in an ipso or cine way.
In this sense, intramolecular processes offer the possibility to synthesize interesting cyclic products
from acyclic structures.
However, to this moment only a few examples of intramolecular cine substitution applied to cyclic
starting materials has been reported, and no studies of the probable influence of the
stereoelectronic nature of the leaving group (LG) over the mechanism, have been developed.
Herein, we describe an intramolecular cine substitution on conformationally restricted carbohydrate
systems to show some light over the stereoelectronic requirements of the LG to promote the cine
mechanism against others.
We have studied the evolution of 1-glycosyl and 4-glycosyl radicals, with proper adyacent LGs,
resulting from a 1,5-Hydrogen Atom Transfer (HAT) process to obtain spiroacetalic and dioxabicyclic
compounds respectively. |
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