Stereochemistry Two major categories Carvones Enantiomers differ in enantiomers non super imposable mirror images o Only differ in odor and polarimetry diastereomers very different chemical properities 02 12 2015 Odor tests by seeing if they smell different o But we have to have proper sniffing technique wafting Small percent of the population that can t distinguish between the two enantiomers It s a genetic issue Polarimetry o Polarized light will rotate a certain number of degrees Either to the right or to the left o They are visual and very sensitive The enantomiers should be equal and opposite however they are very sensitive and can detect very slight differences such as a scratch or impurity on the test tube It s okay if the numbers aren t exactly the same Geometric isomers Find the mechanism o What happened one functional group rotated 180 degrees o Can that happen without any help No because of the double bond Energy comes form light o E plancks constant frequency of the light o ultraviolet But there s not enough ultraviolet radiation from a lab light bulb for the reaction to work by itself You need Br2 How much energy to break a bromine bond 46 kcal to break That s about 600 nm which is in the visible light light spectrum Since light is involved it s probably going to be homolyctic cleavage Radicals are very reactive o It s sole purpose is to find another electron o The pi bond in the carbon carbon double bond o Will break the carbon carbon double bond Rules o No mysterious chemicals can come in o Carbons can only have four bonds o Follow arrow convention o No really weird species Safety Bromine Br be careful it is painful o Switch out your gloves 02 12 2015 02 12 2015