19: Compounds With Carbon–Carbon Multiple Bonds II: Cyclization Reactions
- Page ID
- 24618
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The structural requirements for a molecule destined to undergo radical cyclization are that it contain a substituent from which a radical (almost always a carbon-centered one) can be generated and that it have a properly positioned multiple bond. Carbohydrates that meet these requirements include unsaturated iodides, bromides, thionocarbonates, cyclic thionocarbonates, xanthates, and phenyl selenides. Ring formation in the reactions of these compounds usually is regiospecific and often highly stereoselective.