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The mixture of the R and (R)-RNH₂ (S)-RNH₂ S enantiomers of the amine is reacted with the (S)-RCOOH S enantiomer of 2-chloropropanoic acid to + - produce a mixture of (R)-RNH₃ (S)-RCOO diastereomers of the salt. + (S)-RNH₃ (S)-RCOO Since diastereomers have different physical Separate properties, the mixture can be separated by conventional separation + + techniques. (R)-RNH₃ (S)-RCOO (S)-RNH₃ (S)-RCOO Each of the pure NaOH NaOH diastereomers of the salt is then treated with a strong base to regenerate (R)-RNH₂ (S)-RNH₂ the pure enantiomers of the amine. 7.26 a) The DU of X = 1. Therefore X has one ring or one pi bond. b) Unknown X must have a double bond because it reacts with H₂ to form a saturated compound, Y, with DU = 0. c) Compound X has a chirality center because it rotates plane polarized light. Compound Y is achiral, so hydrogenation of the double bond destroys the chirality center by converting the double bond group into an alkyl group that is the same as another alkyl group on the chirality center. CH₂CH₃ CH₂CH₃ C H₂ H C H CH₃ catalyst CH₃CH₂ CH₃ X (or enantiomer) Y 104