Exam 3 Flashcards
Compounds containing both double and triple bonds are called
-enynes
When naming a compound that has both an alkene and alkyne, which one takes priority
Alkene
Ex)1-nonen-8-yne
1=Alkene on first carbon
What is the exception for an alkyne being a higher priority over Alkene
If a lower number can be assigned to the alkyne instead of the Alkene then the alkyne take priority
What is the exception if the Alkene and alkyne are equidistant
The whichever one is closest to the substituent is higher priority
CH3CH2CH2CH2
Butyl
1-Butenyl
CH3CH2CH=CH
1-Butynyl
CH3CH2C-=C
(Triple bond)
Vic in Al dihalides are prepared by
Addition of X2 to an Alkene
Add one H and a Hlogen to each carbon connected to the Alkene
Final product= alkane
How to prepare an alkyne (typically from alkane)
Strong base reagents: KOH or NaNH2
For halgenation: 1eq of X2 will produce
A trans Alkene
Halogenating reagents
Cl2 or Br2
CH3CO2H
Reagents for acid catalyzed Hydration
- HgSO4
- H2SO4, H2O
Produces. Ketone
Heats of hydrogenation shows
First step of this reaction is more exothermic than the second step
-176 kj/mol vs -137kj/Mol which is more exothermic
-176kj/mol
Describe connect break off method
A method for terminal alkynes to make a hydrocarbon
(Slide 1 of 9.2 slides)
Relationship between terminal alkynes and alkenes/alkanes
Terminal alkynes are more acidic than alkenes or alkanes
Which base should I choose to create sodium acetylene: NaOH or NaNH2
Explain why
For deprotanation of an terminal alkyne we need the strongest base out of the two. NaNH2 is the strongest bc it has a stronger conjugate acid than NaOH
SN1 step 1 reaction
Leaving group leaves and carbocation is formed
For an inversion SN2 reaction what carbon changes it’s stereochemistry
The carbon bearing the leaving group is invented, meaning it changes stereochemistry
For an SN2 reaction has a strong nucleophile it’s attacks from
The back and inversion of stereochemistry occurs
