270 likes | 1.06k Views
Chapter 7 - Stereochemistry. Enantiomers of bromochlorofluoromethane. Non-superimposable mirror images – Enantiomers. YSU. Figure 7.1. 7.12 Optically active molecules of biological importance. YSU. YSU. $100 billion sales worldwide in 2000
E N D
Chapter 7 - Stereochemistry Enantiomers of bromochlorofluoromethane Non-superimposable mirror images – Enantiomers
YSU Figure 7.1
7.12 Optically active molecules of biological importance YSU
YSU $100 billion sales worldwide in 2000 Account for 32% of the $360 billion total drug sales
7.2 The Chirality Center YSU Carbon atom is asymmetricC is a stereogenic center Enantiomers are stereoisomers since the atoms at the stereogenic carbon are arranged differently in space.
7.3 Symmetry in achiral structures YSU Mirror images of chlorodifluoromethane are superimposable Figure 7.2 Achiral i.e. not chiral
7.4 Optical activity Figure 7.4 YSU Typical polarimeter setup : [a]D = 100 x (rotation)/(cell length) x (concentration)
7.8 Enantiomers same physical properties except rotation of plane polarized light one enantiomer positive rotation (+) other negative rotation (-) YSU
Which molecules contain chiral (stereogenic) centers? YSU The stereogenic C must have 4 different groups attached
7.5 Absolute and Relative Configuration YSU Absolute Configuration – Actual arrangement of substituents in space (+)-2-butanol and (-)-2-butanol, but which is which? Relative Configuration - Configuration relative to another compound. Pre-1951, compounds could be related to each other but the absolute configuration was not able to be determined.
7.6 Nomenclature - Use of the Cahn-Ingold-Prelog System YSU (R) and (S) R enantiomer S enantiomer R - Rectus - the clockwise arrangement of groups S - Sinestre - the counterclockwise arrangement of groups
7.7 Fischer projection formulas Figure 7.5 YSU
7.9 Reactions that create a Chirality Center Figure 7.6 YSU
7.10 Chiral molecules with two Chirality Centers Figure 7.7 YSU
7.10 Representations of (2R, 3R)-dihydroxybutanoic acid YSU Figure 7.8 Conversion of “zig-zag” picture to Fischer projection All the same molecule: (a) and (b) differ only by bond rotation ; (b) leads to correct Fischer projection
7.11 Achiral molecules with two Chirality Centers Figure 7.9 YSU
Meso-2,3-butanediol Figure 7.10 YSU
7.12 Stereogenic centers in cholic acid YSU Figure 7.11
7.12 Optically active molecules of biological importance YSU
7.13 Reactions that produce diastereomers Figure 7.12 YSU
7.13 Reactions that produce diastereomers Figure 7.12 YSU
7.14 Resolution of a chiral substance into its enantiomers Figure 7.13 YSU