orgo ch4

cis

carbons are on same side, are meso

trans

carbons on opposite side, are enantiomers

priority rules

highest atomic number, higher atomic mass, multiple bonds

z

high priority group same side

e

high priority group opposite side

chiral carbon or stereogenci center

a carbon with 4 different groups

enantiomer

pair of stereoisomers that are not super imposable mirror images of each other, exhibiting optical activity

achiral

no plane of symmetry

S

counterclockwise configuration of substituents around chiral center

R

clockwise configuration of substituents around chiral center

diasteromers

stereoisomers of compound that are not mirror images

meso compound

stereoisomer with asymmetric center but achiral cause of internal symmetry

racemic mixture

half and half mixture of two enantiomers, optical rotation zero

enantiomeric excess

observed rotation/ specific rotation of pure isomer times 100

pair of enantiomers

r changes to s, s changes to r

how to know molecules are diastereomers

only few change from r to s and s to r, others stay the same

how to know molecules are meso compounds

the r and s stay don’t change in two compounds