Term
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Definition
| a molecule that is not superimposable on its mirror image |
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Definition
| each isomer of the image-mirror image pair |
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Definition
| compounds having structures that are superimposable on their mirror images; in contrast with chiral molecules |
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Term
| asymmetric atom/stereocenter |
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Definition
| an atom that is connected to four different substituent groups |
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Term
| molecules with one stereocenter are always _____ |
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Definition
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Term
| the only criterion for chirality is _____ |
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Definition
| the nonsuperimposable nature of object & mirror image |
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Term
| plane of symmetry (AKA mirror plane) |
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Definition
| one that bisects the molecule so that the part of the structure lying on one side of the plane mirrors the part on the other side |
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Term
| chiral molecules cannot have _____ |
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Definition
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Definition
| an enantiomer that rotates the plane of light in a clockwise sense as the viewer faces the light source; compound is referred to as the (+) enantiomer |
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Definition
| the enantiomer that effects counterclockwise rotation of light; called the (-) enantiomer |
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Definition
| the special interaction with light of dextrorotatory and levorotatory molecules |
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Term
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Definition
| enantiomers involved in optical activity |
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Term
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Definition
| the plane in which the one resulting beam of light oscillates after ordinary light is passed through a polarizer which filters away all but one light wave |
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Term
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Definition
| a rotation of the plane of polarization resulting from an interaction between the different electric fields of the left & right halves of a chiral molecule and a beam of plane-polarized light |
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Term
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Definition
| an instrument that measures optical rotations |
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Term
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Definition
| the actual spatial arrangement of the substituent groups on a molecule |
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Term
| there is no straightforward correlation between the sign of rotation and the _____ |
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Definition
| structure of the particular enantiomer |
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Term
| 3 sequence rules to assign priorities to substituents |
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Definition
1. first look at the atoms attached directly to the sterocenter; a substituent atom of a higher atomic number takes precedence over one of lower atomic number; in regard to isotopes, the atom of higher atomic mass receives higher priority
2. when two substituents have the same rank when considering the atoms directly attached to the stereocenter, proceed along the two substituent chains until a point of difference is reached
3. double and triple bonds are treated as if they were single; the atoms in them are duplicated or triplicated at each end by the atom bonded to it |
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Term
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Definition
| a simplified way of depicting tetrahedral carbon atoms & their substituents in two dimensions |
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Term
| in a Fischer projection, the horizontal lines signify bonds directed ______ the viewer |
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Definition
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Term
| in a Fischer projection, the vertical lines are pointing _____ |
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Definition
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Term
| if you rotate a Fischer projection by 90 degrees, does the result depict the spatial arrangement of the original molecule? |
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Definition
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Term
| any _____ exchange of substituent groups on a molecule turns on enantiomer into its mirror image |
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Definition
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Term
| 3 steps to assign absolute configurations to Fischer projections |
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Definition
1. draw the molecule as any Fischer projection
2. rank all the substituents in accord with the sequence rules
3. place group d on top by a double exchange if necessary |
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Term
| is "R" associated with clockwise or counterclockwise? |
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Definition
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Term
| is "S" associated with clockwise or counterclockwise? |
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Definition
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Term
| the Fischer stencil represents an _____ conformation & therefore does not depict the molecule in its most stable form, which is _____ |
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Definition
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Term
| to make stereochemical assignments, one treats each stereocenter ______ |
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Definition
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Term
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Definition
| stereoisomers that are not related as object & mirror image & therefore are not enantiomers |
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Term
| how are diastereomers different from enantiomers? |
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Definition
| diastereomers are not mirror images of each other |
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Term
| do daistereomers have the same or different physical & chemical properties? |
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Definition
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Term
| what is the relationship between the number of stereocenters a compound has & its maximum number of stereoisomers? |
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Definition
| a compound with "n" stereocenters can have a maximum 2^n stereoisomers |
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Term
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Definition
| a compound that contains two (or even more than two) stereocenters but is superimposable with its mirror image |
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Term
| a characteristic feature of a meso compound is the presence of ______ |
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Definition
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Term
| the formation of chiral compounds from achiral reactants yields _____ |
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Definition
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Term
| optically inactive starting materials furnish _____ products |
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Definition
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Term
| halogenation at the stereocenter leads to a _____ mixture |
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Definition
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Term
| the formation of a second stereocenter gives rise to _____ |
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Definition
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Term
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Definition
| a reaction that leads to the predominant formation of one of several possible stereoisomeric products |
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