Organic Chemistry 1 Flashcards
sp2
trigonal planar or bent
120°
sp3
tetrahedral, trigonal pyramidal, bent
109.5°
sp3d
trigonal bipyramidal, seesaw, t-shaped, linear
90°/120° or 180°
sp3d2
octahedral, square pyramidal, square planar
90°
octet rule exceptions
hydrogen and helium: stable with 2 e- in valence shell
boron and beryllium: stable with 6 e- in valence shell
atoms from third period or higher can accept more than 8 e-
amine
aldehyde
alkoxy
gem/vic
mesyl/tosyl
amide
anhydride
aryl
benzyl
hydrazine
vinyl
allyl
nitrile
epoxide
enamine/imine
acyl
sulphone
nitro
acetal/ketal
hemiacetal/hemiketal
conformational isomers
differ by rotation around a single bond
*** not true isomers
structural isomers
same formula, different bond-bond connectivity
enantiomer
same bond-bond connectivity, non-identical, non-superimposable mirror images
contain at least one chiral center
1) have opposite R/S configuration at every chiral center
2) rotate plane-polarized light to same degree, but in different directions
3) have all same physical properties except for:
a. how they rotate plane polarized light
b. the products they form when reacted with another chiral compound
diastereomers
same bond-bond connectivity, non-identical, not mirror images
- geometric isomers
- epimers
- anomers
geometric isomers
diastereomer → cis/trans
cis: usually have a dipole moment, often experience steric hindrance = higher energy molecule
epimers
diastereomer → differentiations only at one chiral center
*** many pairs of carbohydrates are epimers
anomers
diastereomer → differentiations only in spatial orientation at anomeric carbon of a ring structure
α = OH/OR same side as CH2OH β = OH/OR opposite side as CH2OH
meso compounds
two or more chiral centers that contain a plane of symmetry
bases
abstract protons
e- dense and have full or partial negative charge
strongest base → forms strongest, most stable bond with hydrogen (acid/base equilibrium prefers the conjugate acid)
nucleophiles
attack carbons
e- dense and have full or partial negative charge
best nucleophile → reacts the fastest with an available electrophile
leaving groups
take both e- from the bond with them
best leaving groups → most stable after they leave
E1
carbocation formed + methyl/hydride shifts
product = planar
favored by → weak bases, 3° C only, polar protic solvents
SN1
carbocation formed + methyl/hydride shifts
product = racemic mixture
favored by
→
poor nucleophiles,
3° C only, polar protic solvents
E2
no carbocation + no methyl/hydride shifts
product = planar
favored by → strong and/or bulky bases
SN2
no carbocation formed + no methyl/hydride shifts
product = inversion of relative configuration
favored by → strong and/or bulky bases, methyl/1°/2° C
melting point / boiling point
↑ bp + ↑ mp = ↑ chain length/molecular weight
↓ bp = ↑ branching
***straight chain alkanes have highest mp, among branched alkanes → increased branching = ↑ mp
alkenes
nucleophiles + weakly e- withdrawing
stability: tetrasubstituted > trisubstituted > disubstituted > mono substituted > unsubstituted
ethers
very non-reactive + weakly polar
most non-polar species are soluble in ethers
low boiling point → no H bonding
***make excellent solvents
basicity
function of thermodynamics → describes how much the molecule wants to react, not how quickly
nucleophilicity
function of kinetics → describes how easily/readily a molecule will react, but not how stable the new bond will be
basicity vs nucleophilicity
steric hindrance → favors basicity
reactivity (low stability) → favors basicity
carbocations
mechanisms will always proceed through the most stable carbocation (unless peroxide is present)
stability: 3° > 2° > 1°
polar protic
capable of H bonding
favor SN1
water, methanol, ethanol, ammonia, acetic acid
formal charge
= (valence e-) - (non-bonding valence e- in lone pairs) - (# of bonds)
sp
linear
180°
alcohols
less acidic than water
acidity: 3° > 2° > 1°
polar aprotic
cannot form H bonds
favor SN2
tetrahydrofuran (THF), acetone, dimethylforamide (DMF), acetonitrile (MeCN), dimethylsulfoxide (DMSO)
alcohol oxidation
1° alcohol → aldehyde → carboxylic acid
2° alcohol → ketone
3° alcohol → cannot be oxidized further
oxidizing agents: O3, Cr2O7, CrO4, KMnO4, Jones, Collins, PCC, PDC
alcohol reduction
NaBH4 → can only reduce aldehydes and ketones
LiAlH4 and H2/pressure → can reduce aldehydes, ketones, carboxylic acids, esters
