orgo chem Flashcards
geminal diols what
spontaneously dehydrate (lose water molec) to produce carbony comounds
diols with hydroxyl groups on the same carbon are called _____, and diols with hydroxyl groups on adjacent carbons are called ___
geminal (hydrates)
vicinal
diols
alcohols with two hydroxyl groups are called what
diols
or glycols
esters are what
carboxylic acid derivatives
____ isomers are the least similar of all isomers
structural
what do structural isomers share?
molecular formual - molecular weight is the same
physical properties
characteristics of processes that dont change the composition of matter,s uch as melting point, boiling point, soubility, odor, colour and density
chemical properties
reactivity of molecule with other molecules and result in changes in chemical composition
in organic chem, this is mostly in functional groups
stereoisomers share what
atomic connectivity - same structural backbone
conformational isomers
differ in rotation around single bonds
configurational isomers
can be interconverted only by breaking bonds
anti conformation
staggered - two largest groups are antiperiplanar (same plane, opposite sides) - most energetically favourable type of staggered conformation (lowest energy state)
gauche
two largest groups are 60 degrees apart
totally eclipsed is what energy state?
highest
ring strain factors
angle strain, torsional strain, and nonbonded strain (steric strain)
angle strain
results when bond angles deviate from their ideal values by being stretched or compressed
torsional strain
cyclic molecules must assume conformations that have eclipsed or gauche interactions
nonbonded strains (vdw)
nonadjacent atoms or groups compete for same space
dominant source of steric strain in flagpole interactions
cyclohexane three main conformaions
chair
boat
twist (skew boat)
hydrogen atoms that are perpendicular to plane of ring
axial
hydrogen atoms that are parallel
equatorial
chiral if wht
mirror image cannot be superimposed on original object
enantiomers have nearly identical ______ proerites and chemical peoperties, but they rotate ________ light in opposite directions and react differently in chiral environments
physical
plane polarized light
d- or + to refer to _______ rotation, l- and - to refer to ______ rotation
clockwise
counterclockwise
racemic mixture displays ____ optical activity
no
meso compound
a molec with chiral centers that has an internal plane of symmetry
two halves that are mirror images - thus as a whole they are not optically active
relative configuration of chiral molecule
configuration in relation to another chiral molecule
absolute conformation of chiral molec
exact spatial arrangement of these atoms or gruops - independent of other molecules
priority in e and z formation / designation is assigned based on what
atom bonded to double bonded carbosn - higher the atomic number, higher the priority
alkene is named _____, if the two highest priority substients on each carbon are the same side of the double bond,
Z
if two highest priority substituents are on opposite sides, they are named ___
E
when drawing the circle for r and s, if the roation is counterclockwise, then it is called what and what if it is clockwise
S
R
s and p orbital shapes
s - spherical and symmetrical centered around nucleu
p - composed of two lobes located symmaetrically about the nucleus and contains a node - area where probability of finding an e- is zero
if the signs of the wae functions are the same, a lower energy more stable ____ orbital is produced, and if they are different, a higher energy (less stable) ____ orbital is prodcued
bonding
antibonding
how are sigma bonds formed?
head-to-head or tail-to-tail overlap of atomic orbitals - most common bond in organic compounds and on MCAT
single bonds are what kind of bond
sigma bonds
pi bond formation how
when two p orbitals line up in a parallel fashion - e- cloud overlaps
what forms a double and triple bond
double is pi on top of sigma
tripe is sigma and two pi
which is weaker pi or sigma?
pi bonds are weaker
strength is additive though - double and triple bonds are stronger than single
conjugation requires alternating single and multiple bonds because this pattern __________ down the backbone of the molecule
aligns a number of unhybridized p orbitals
____ electrons can delocalize through p-orbital system, adding ___ to the molec
pi
stability
lewis acid is what
e- acceptor
lewis base is what
e- donor
bronsted lowry acid
e- donor
bronsted lowry base
e- acceptor
nucleophiles tend to have ______ or ____ bonds that can be used to form covalent bonds to electrophiles
lone pairs
pi
how can you identify nucleophiles (most)
carbon, hydrogen, oxygen, or nitrogen (CHON) with a minus sign or lone pair
nucleophilicity is determined by four major factors which are
charge - nucleophilicity increases with increasing electron density - more negative charge
electronegativity - nucleophilicity decreases as EN increases because these atoms are less likely to share e- density
steric hindrance - bulkier molecues are less nucleophilic
solvent - protic solvents can hinder nucleophilicity by protonating the nucleophile or through hydrogen bonding
leaving groups
molecular fragments that retain e- after heterolysis
nucleophilic attack will only occur when
if the reactants are more reactive than the products
steric hindrance
describes prevention of rxns at particular location within molecule due to size of substuent groups
primary secondary tertiary alcohols being oxidized to what
primary - aldehydes
secondary - ketons
tertiary - cannot be oxidized bc they are already as oxidized as they can be without breaking a carbon-carbon bond
jones oxidation
chromium trioxide Cro3 - dissolved with dilute sulfuric acid in acetone
treatment of phenols with oxidizing agents produces compounds called what
quinones
hydroxyquinone vs hydroquinone`
contains two carbonyls and a variable number of hydroxyl groups
benzene ring with two hydroxyl groups
electron withdrawing groups like oxygen stabilize what and what destabilizes th same ting
organic anions
electron donating groups like alkyl groups
ketones are slighltly less likely to reat with nucleophiles because what
extra alkyl group destabilizes the carbanion and increase steric hindrance
are carboxylic acids polar
yesc
carboxylic acid acidity is due to what
resonance stabilization and can be enhanced by addition of electronegative groups or greater ability to delocalize charge
which hydrogen is the most acidic proton on a carboxylic acid?
hydroxyl hydrogens
protonating the c=o makes electrophilic carbon what
even more ripe for nucleophilic attack
conjugated molex
molecs with unhybridized p orbitals
UV spectroscopy is most useful for what
studyign compounds containing double bondns or heteroatoms with lone pairs that create conjugated systems
in proton nmr, each peak or group of peaks that are part of a mulitplet represents what
single group of equivalent protons
splitting of a peak in proton nmr represents what
the number of adjacent hydrogens
peak will be split into n+1 subpeaks where n is number of adjacent hydrogens
proton nmr is good for what
determining relative no. of protons and their relative chemical elements
showing how many adjacent protons thera re by splitting patterns
inferring certain functional groups
solubility based extraction procedures
extraction
filtration
recrystallization
amides are formed how
condensation reaction of other carboxylic acid derivatives and ammonia or an amine
cyclic amides are called what
lactams
esters are formed how
by the condensation reaction of carboxylic acids or anhydrides with alcohols
anhydrides are formed how
by condenstation reaction of two carboxylic acids
steric hindrance
when a reaction doesn’t proceed due to the size of the substituents
