The Anomeric Effect and Related Stereoelectronic Effects at Oxygen

Contenu

A. Stereoelectronic Effects on Structure.- 1. Introduction.- 2. The Anomeric Effect.- 3. The Reverse Anomeric Effect.- 4. The Exo-Anomeric Effect.- 5. The Generalised Anomeric Effect.- a. Sulphur Compounds.- b. Transmission through Phosphorus.- c. Transmission through Sulphur.- 6. The Gauche Effect.- B. The Electronic Basis of the Effects.- 1. Introduction.- 2. The Status of Lone Pair Electrons.- a. Evidence from Hydrogen-bonding.- b. Electron Density Measurements.- 3. Calculations on X?Y Systems.- 4. Effects on Bond Lengths and Angles.- 5. Effects in Furanoses.- 6. The Stereoelectronic Basis of the Anomeric Effect.- a. The Structure of CH2F2.- b. Bonding in ROCH2X.- c. Bonding and Restricted Rotation in Dimethoxymethane.- d. The Generalised Anomeric Effect.- e. The Reverse Anomeric Effect.- f. The Exo-Anomeric Effect.- 7. Related Stereoelectronic Effects.- a. The Anomeric Effect at sp2 centres.- b. The Gauche Effect.- C. Stereoelectronic Effects on Reactivity: The Kinetic Anomeric Effect.- 1. Introduction.- a. The Use of sp3-hybrid Lone Pairs.- b. The Stereoelectronic Basis of the Kinetic Anomeric Effect.- 2. Reactions of the Acetal Group.- a. Acetal Hydrolysis.- b. Acetal Formation.- c. Acetal Oxidation.- 3. The Hydrolysis of Orthoesters.- a. Hemiorthoesters.- 4. Carbonyl-Oxygen Exchange Reactions of Esters and Amides.- 5. The Hydrolysis of Imidate Esters: Stereoelectronic Effects at Oxygen and Nitrogen.- 6. Reactions of Phosphate Esters.- 7. Radical Reactions.- 8. Enzyme Reactions.- D. Appendix.- 1. Canonical Lone Pair Description.- 2. Hybrid Lone Pair Description.- E. References.- F. Subject Index.