organic chemistry Flashcards
what is the formula of isobutyl
CH3CH(CH3)CH2
what is the formula of sec-butyl
CH3CH2CHCH3
what is the formula of tert-butyl
CH3CH(CH3)CH3
boiling point increases with
more carbons
less branching
polarity
more halides (less F though)
weight
melting point increases with
compact molecules (odd #c chains are less compact than even #c)
what is a conformational isomer/conformer
different spacial arrangement of atoms as a result of the rotation about a single bond
anti vs gauche bonds
anti 180
gauche 60
between adjacent carbons in staggered conformation
what is torsional strain
repulsion between aligned electron pairs in eclipsed bonds
what is steric strain/van der waals strain
atoms are too close together and destabilizing this compound
what is angle strain and when does it happen
happens in cycloalkanes
distortion of bond angles from normal values as a result from a weak bond/poor overlap of orbitals
what are stereoisomers
same atom connection but different arrangement in space (cis vs trans)
chiral vs achiral
chiral: mirror images but not superimposable
achiral: superimposable mirror images and potentially a line of symmetry
what is an enantiomer
chiral stereoisomers
in newman projections where the Y is upside down the left side and right side are dashes or wedges
left are wedges and right are dashes
conditions for optical activity
substance must be chiral
one enantiomer has to be present more than the other
molecules that rotate in light clockwise vs counterclockwise are called what and have what charge
clockwise: dextrorotatory and +
counterclockwise: levorotatory and -
enantiomers rotate opposite directions
specific rotation formula
[a] = a (observed rotation) / length (dm) x concentration (g/mL)
three formulas relating to enantiomeric excess
ee = observed specific rotation / a of pure enantiomer
ee % = % major - % minor
100% = % major + % minor
what are diastereomers
stereoisomers that are not mirror images
one chiral center stays the same
cis and trans are diastereomers
what is a meso compound
achiral molecule with chiral centers (plane of symmetry)
optically inactive
when adding halogens to alkenes what stereoisomers are formed based on cis/trans conformation
cis: stereoisomers are (S,S) and (R,R)
trans: stereoisomers are (R,S) and (S,R)
what do Sn and E reactions give as products
Sn2: single product (inverted con.)
Sn1: single product unless halogen is bonded to chiral center then its enantiomers (R and S)
E2: E and Z isomers unless only one beta carbon has H then only one product (E is m.p.)
E1: E and Z isomers are formed (E is m.p.)
what does anticoplanar mean
atoms that are 180 degrees apart
adjacent axial atoms are anticoplanar
product distribution formula
p.d. = (number of Hs)(relative reactivity) / sum of relative amount of all products
