II. Minimizing Steric Interactions: The Least-Hindered Pathway
- Page ID
- 23958
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As mentioned in the previous section, stereoselectivity in reactions of carbohydrate radicals depends on the location of the radical center. When a radical is centered on a carbon atom adjacent to a ring oxygen atom a combination of stereoelectronic, conformational, and steric effects determines stereoselectivity, but reactions of radicals centered on other carbon atoms are controlled primarily by steric effects. For the latter group the major stereoisomer in a bimolecular reaction is the one produced by a molecule and a radical approaching each other along the least-hindered pathway.