STEREOCHEMISTRY OF COMPOUNDS WITH Csp3 STEREOCHEMISTRY OF COMPOUNDS WITH Csp3 (1S,2R)- 2-Methylcyclobutanol STEREOCHEMISTRY OF COMPOUNDS WITH Csp3 (R) (R) (1R,2R)-2-amino-5-chloro-1-methylcyclopentanol STEREOCHEMISTRY OF COMPOUNDS WITH Csp3 (S) (S) (1S,2S)-2-methylcyclohexanol STEREOCHEMISTRY OF COMPOUNDS WITH Csp3 Stereochemical nomenclature of compound according with older rules (used mostly in older literature and biology) When the compound is placed in Fisher projection according with all the rules, that is the carbon atom in highest oxidation state at the top and the main carbon atoms chain perpendicular, then when the group with higher priority is located right , the compound is D- isomer; when the group with higher priority is located left, the compound is L-isomer. Compound at this Fischer formula is D-alanin = (R) -2-aminopropanoic acid All a-aminoacids forming protein structures have got configuration L-. D-glyceraldehyde D-butane-2-ol Physical properties molecules in connection with their stereochemistry Enantiomers differ in the direction they rotate the polarized light only, other physical properties as melting point, boiling point, spectral properties, solubility etc. are the same. a - measured value I - lenght of the polarimetric tube [dm] d - concentration [g/mL] c - concentration [g/100mL] Values of specific rotation are dependent upon temperature and wave length of the light enantiomers have the same value of the specific rotation, but they differ by the sense of rotation D = D line of sodium lamp l = 589 nm Physical properties molecules in connection with their stereochemistry Mixtures of enantiomers: Racemic mixture is formed by 50% of both enantiomers – the measured specific rotation is zero. Mixtures of enantiomers in another ratio than 1 : 1 are optical active Optical purity gives us information about excess of one isomer over the other % optical purity Physical properties molecules in connection with their stereochemistry Stereochemistry of compounds with more stereogenic centers Number of stereoisomers with the number n of stereogenic centers is 2n One half of them are enantiomers DIASTEREOMERS DIASTEREOMERS DIASTEREOMERS ENANTIOMERS ENANTIOMERS Physical properties molecules in connection with their stereochemistry Stereochemistry of compounds with two similar stereogenic centers mesocompounds [2R, 3S] - tartaric acid mesotartaric acid [2S,3S] – tartaric acid [2R,3R] – tartaric acid racemate D-tartaric acid L-tartaric acid PROPERTIES: m.p. density [g/cm2] solubility Interaction of chiral molecule with a active center (SCHEME) ACTIVE INACTIVE Interaction chiral molecules with a substrate and their activity Interaction chiral molecules with a substrate and their activity OVERVIEW OF PROPER ACIDS AND BASES FOR SEPARATION OTHER SOURCES OF CHIRALITY HELICITY AXIAL CHIRALITY ATROPOISOMERIE