| Abstract
| - The factors controlling the highly α-selective C-glycosylation of ribose derivatives were determinedby examining the stereoselective reactions of 18 ribose analogues differing in substitution at C-2, C-3, andC-4. The lowest energy conformers of the intermediate oxocarbenium ions display the C-3 alkoxy group ina pseudoaxial orientation to maximize electrostatic effects. To a lesser extent, the C-2 substituent prefersa pseudoequatorial position, and the alkyl group at C-4 has little influence on conformational preferences.In all cases, the product was formed by stereoelectronically preferred inside attack on the lowest energyconformer.
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