Alkenes Flashcards
Can methene exist
no
List all the alkenes from 2C to 6
Ethene
Propene
Butene-1
Pentena-1
Hexene-1
a double bond is composed of what bonds
1 sigma bond
1 pi bond
what does the double bond of carbon result in
sigma bond results in overlapping sp2 hybrid orbitals
pi bond results in overlapping p orbitals
do double bonds rotate at room temperature
no so steroisomers must be observed because in organic chem if you wanna identify you gotta do this
what are the steps for E-Z designation
- Atoms of higher atomic number have higher priority.
- If the first atoms are similar, higher priority is assigned to the group that has an atom with a higher atomic number at the first point of difference.
- If atoms are all the same type, the group that contains a higher number of atoms will be given higher priority.
what is a Z configuration
If the two groups with higher priority are on the same side of the double bond
what is an E configuration
If the two groups with higher priority are on the opposite side of the double bond = E configuration
*Easy way to remember: E is for enemy, which are in opposition to each other in battle
what type of alkene is more stable - trans or cis alkene?
transalkene
why is a cis-alkene less stable than a trans-alkene
cis alkene will produce greater steric strain, as the higher priority groups are closer to each other than when in trans configuration
how can you make an alkene more stable in general
become more substituted
why are substituted alkenes more stable
due to the delocalisation of electron density that produces a stabilising effect
what do all elimination reactions involve
transfer of a proton and the loss of a leaving group
what are the two steps of an elimination reaction
- concerted process [e2]
- stepwise process [e1]
what are the two types of elimination reaction
E1
E2
