Learning Guide for Chapter 6 - StereochemistryI. Stereoisomers containing C=C p 1II. Introduction to chirality - compounds with one stereoisomer - p 5 Chirality Recognizing chiral compounds Labeling stereocenters as R or SIII. Compounds with two or more stereoisomers - p 9 Diastereomers and meso compounds Fischer projectionsIV. Physical properties of chiral compounds - p 14 Melting point, boiling point, etc Biological environments Optical activity Separation of enantiomers Determination of stereochemical correlationI. Stereoisomers containing C=CWhat do two compounds which are constitutional isomers have in common? How are they different?Give the molecular formula and one constitutional isomer for each of the following compounds.Are these compounds constitutional isomers of each other?What do two compounds which are stereoisomers have in common? How are the different?Draw line structures for two different molecules with the condensed structure shown.CH3CH=CHCH3LG Ch 6 p 2What keeps these two compounds from being the same?Why aren't these two structures the same as the ones above? What relationship do they have?Draw a constitutional isomer, a stereoisomer, and a conformation of the following compound.constitutionalisomerstereoisomerconformationsame formula?same bondingsequence?same shape?same compound?Do all compounds containing a C=C have stereoisomers?How many stereoisomers does the following compound have? Why?How many stereoisomers are possible for a compound containing a C=C?How can you tell if a compound with a C=C will have a stereoisomer?LG Ch 6 p 3Determine whether or not the compounds below will have a stereoisomer, and for those that will, draw it.What is a stereocenter?carbon - switch two substituents, get a new compoundCan a compound containing a C=C have only one stereocenter?LG Ch 6 p 4When can we use cis and trans to label the two stereoisomers?Which of these is cis, and which is trans?Why can't cis and trans be used on the following compound?In the following examples, the #1 substituent has priority over the #2 substituent. Which is E and which is Z?12212121Label the following as E or Z and explain why.ClOHLG Ch 6 p 5II. Introduction to ChiralityWhat does it mean to say that an object is chiral? What about achiral?Many everyday objects are chiral. Consider the following. Are they chiral or achiral? Is the mirror image of the object the same, or different?spoonforkknifesocksshoesglovesstriped quilt trianglesscrewnailscissorsfolding student deskTetris shapeshandDNA helixHow can a molecule be chiral?HBr OHUsing models, make the compound below. Then construct its mirror imageAre they the same (are they superimposable)?LG Ch 6 p 6Construct the compound below, and its mirror image.Are these compounds superimposable?HH OHIs the original compound chiral?What is the relationship between these two compounds?HBr OHHOHBrDoes the original compound have an enantiomer?Are the central carbon atoms stereocenters?How can you determine if a molecule is chiral?1) Is the mirror image superimposable?OHOHLG Ch 6 p 72) Is there a plane of symmetry in the molecule?OH OH3) How many asymmetric carbons are in the molecule?OHOHOHOHOH OHOHClOBrWhich of the following molecules are chiral? Which have planes of symmetry? Where are the asymmetric carbons? Where are the stereocenters?LG Ch 6 p 8How are enantiomers labeled?OHOHOHCl ONH2BrBrPractice:How is this label included in the name?LG Ch 6 p 9III. Compounds with two or more stereocentersConsider the following compound. How many stereocenters does it have? How many stereoisomers could it have?OHClWhich stereoisomers are enantiomers?Which stereoisomers are diastereomers?BrBrNext, consider the following compound. How many stereocenters does it have? How many stereoisomers does it have?Enantiomers? Diastereomers?LG Ch 6 p 10What is the difference between the following compounds?BrBrBrConsider the following compound. How many stereocenters does it have? How many stereoisomers does it have?Enantiomers?Diastereomers?LG Ch 6 p 11Isomersconstitutional isomers stereoisomersdiastereomersenantiomersAll of the isomers we have seen so far can be related as follows:OH OHOHOHOHOHOH OHOH OHOH OHOHOHOH OHOHOHOHOHOH OHOHOHOHOHOH OHOHOHClassify the following compounds as identical, enantiomers, diastereomers, meso, or constitutional isomers.OHOHOH OHLG Ch 6 p 12Fischer ProjectionsWhen are Fischer projections useful?Draw a Fischer projection of the following molecule:OOHOHlacticacidConvert the following Fischer projection to a line structure.CHOH OHH OHOHH OHriboseWhich shows the relationship between the stereocenters better?Which is the more stable conformation?Why are the OH's all on the right in the Fischer projection, but some up and some down on the line structure?What is the relationship between the following molecules?CHOH OHH OHCH2OHCHOHHOHHOCH2OHCHOH OHHO HCH2OHCHOHHOHHOCH2OHLG Ch 6 p 13CH2OHH OHH OHCH2OHCH2OHHO HH OHCH2OHCH2OHOHHHHOCH2OHCH2OHHHOHHOCH2OHLabel each stereocenter as R or S:COOHH2N HCH3CH3Br HH BrCH3Label each of the following molecules as D or L:CHOH OHHO HH OHH OHCH2OHCHOHHOOHHHHOHHOCH2OHCHOHO HHO HH OHH OHCH2OHCHOOHHOHHHHOHHOCH2OHWhat is the relationship between the first two molecules? What about the second two? What about the middle two?Since D and L only give the stereochemistry of one stereocenter, how can you tell what the rest are?LG Ch 6 p 14IV. Physical Properties of Chiral CompoundsRegular physical propertiesWhat are some of the physical properties that we regularly talk about with organic compounds?How are the properties of enantiomers related?How are these properties of diastereomers related?What is the relationship of the pairs of compounds below? What would you predict about their physical properties?OHOHOHOHCHOH BrBr HCH2OHHBrCHOHBrCH2OHWhy is the odor of a compound an exception to this?OOWhat areas of chemistry are strongly influenced by stereochemistry? Why?LG Ch 6 p 15Optical ActivityHow is plane polarized light different from ordinary light?How do you obtain plane polarized light?Why do polarizing sunglasses work?What would happen if you put two polarizing filters together and then turned them at right angles?What happens when polarized light passes through a solution containing chiral molecules?What is this called?How is it measured?What factors affect the optical rotation? Which is the most useful? How do we eliminate the effect of other