CH 221 1st Edition Lecture 13 Outline of Last Lecture I. More on EnantiomersII. Naming of EnantiomersOutline of Current Lecture III. Plane Polarized LightIV. Enantiomeric ExcessV. Compounds with Two Asymmetric CentersVI. DiastereomersCurrent LectureIII. Plane Polarized Light- A chiral compound is optically active and rotates the plane of polarization in polar-polarized light- If it rotates the plane clockwise, it is (+) Dextroratory- If it rotates the plane counterclockwise, it is (-) Levoratory- Some R enantiomers are (+) and some are (-)- Some S enantiomers are (+) and some are (-)- Ex. (S)-(+)-lactic acid and (S)-(-)-sodium lactate-[α]λT= αlxc -α = observed optical rotation-c=¿ concentration of solution (g/ml)-l = length of tube in decimetersIV. Enantiomer Excess- tells us how much of an excess of one enantiomer is in a mixture- Enantiomeric excess = observed specific rotationspecific rotation of pure enantiomerx 100 %V. Compounds with Two Asymmetric CentersThese notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.- Ex. 3-chloro-2-butanol- Maximum number of stereoisomers = 2n- n = number of asymmetric centers- When both hydrogens are on the same side of the Fischer model, it is called erythro- When hydrogens are diagonal to each other on the Fischer model, it is called threoVI. Diastereomers are stereoisomers that are not enantiomers- They have different physical and chemical properties - Ex. (2S,
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