7. Substitution Reactions
Substitution Comparison
75PRACTICE PROBLEM
The specific rotation of a pure (R)-2-bromobutane solution is -23.1°. When this solution is treated with radioactive bromine, 20% of the bromine in 2-bromobutane is replaced with the radioactive isotope. The resulting 2-bromobutane has a specific rotation of -13.86°, indicating a 60% enantiomeric excess of (R)-2-bromobutane. Based on this information, what can you deduce about the reaction mechanism?
The specific rotation of a pure (R)-2-bromobutane solution is -23.1°. When this solution is treated with radioactive bromine, 20% of the bromine in 2-bromobutane is replaced with the radioactive isotope. The resulting 2-bromobutane has a specific rotation of -13.86°, indicating a 60% enantiomeric excess of (R)-2-bromobutane. Based on this information, what can you deduce about the reaction mechanism?