Organic I Flashcards
method for finding isomers for an alkene
label each C group according to groups attached
count all possible different adjacent pairs, a-b = b-a
this is the number of possible isomers
define constitutional isomer
same molecular formula, different structural formula
define conformational stereoisomer
can be interconverted without breaking bonds
free rotation about C-C bond
sufficient energy at room temp to rapidly interconvert
eg. butane, rotation about C2-C3
why do double bonds restrict rotation?
double bonds have 1 sigma, 1 pi bond
e- in pi bonds are ‘above’ and ‘below’ the axis of rotation
on rotation, p-p overlap reduced to 0
this bond breaking requires more energy than available at room temp
define E-Z
assign priorities
higher priority on the Same side = Z
Opposite = E
amide functional group and naming
CONH2
with double bond O from C
-amide
aldehyde functional group and name
-CHO
O double bonded to C, an end Carbon
-al
ketone functional group and name
C=O not at terminal C
-one
Ester functional group and name
RCO2R
double bond O
-oate
The chain with the double bonded O is the main, the other branch is the -yl group
ether functional group
R-OR
acyl chloride functional group and name
RCOCl
one C=O
-oyl chloride
nitrile functional group
RCN
C triple bonded to N
what groups take priority in numbering of chains?
the amide, aldehyde and carboxylic acid functional groups (all terminal)
formula of the phenyl substituent
C6H5
what are the 3 pairs of functional group isomers?
CnH(2n)O2: esters, RCOOR’, and carboxylic acids, RCOOH
CnH(2n+2)H: ethers, ROR, and alcohols, ROH
CnH(2n)O: ketones and aldehydes
what are the carboxylic acid derivatives?
carboxylic acid, acidic H swapped –> ester
-OR’ of ester swapped for NH2, –> amide
swapped for Cl –> acyl chloride
systematically drawing isomers
start with linear branches then consider chains from shortest to longest
place functional groups on DIFFERENT atoms
monovalent (OH, Cl) replace 1H
divalent (=O) replaces 2H
split chains into 2 parts for esters and ethers
(eg. 5C –> 1C and 4C, or 2C and 3C)
amino acid group
compounds with amine and carbonyl
-NH2 and =O
what element has the lowest electronegativity of common organic elements?
H
hence O-H is very polar (high e- density)
e- density at O singly bonded vs doubly bonded to C
e- density at O singly bonded is LOWER than O doubly bonded
C-O < C=O
what are temporary intermolecular forces?
induced temporary dipoles: attractive forces due to temporary distortion of e- clouds when molecules approach each other from any direction
larger C chain = larger attractive force = higher bp
what organic compounds have hydrogen bonding?
where N-H or O-H bonds are present
alcohols, carboxylic acids, amines, amides
what organic molecules have permanent dipoles?
=O group
ketones, aldehydes …
what is halogenation of alkanes?
possible products?
making haloalkanes by reacting halogen with alkane is the presence of UV light
hydrocarbon in excess, only 1 X substituted
Halogen in excess –> polyhalogenated product, mixture of products