Chapter 9 Flashcards
dehydrogenation
name given to an E2 reaction of an alkyl halide. A strong base removes a hydrogen and halogen to get a pi bond.
vicinal
on the same side of the molecule (1,2)
(in the vicinity of each other)
geminal
on the same carbon (1,1)
(gemini - twins)
double dehydrohalogenation
two reactions occur to make an alkyne
when you have a geminial dihalide what do you need to ensure during a double dehydrohalogenation?
that there are 2 hydrogens to move
terminal alkynes can be deprotonated with a strong base usually ________ or ________ to create strong nucleophiles called sodium alkynide
NaH or NaNH2
terminal alkyne
a triple bond with a hydrogen on the end, they are uniquely acidic due to the hybridization effect
is a carbonyl carbon an electrophile?
yes! the carbon is positive and the oxygen is negative
nucleophilic addition
a carbonyl carbon reacts to make a substituted alcohol
hydrogenation of alkynes
there are three methods commonly used to saturate double and triple bonds
hydrogenation of alkynes: full saturation
- hydrogenation (H2 / Ni, Pd, or Pd-C)
- Wilkonson’s catalyst (H2 / Rh(PPh3)3Cl)
hydrogenation of alkynes: partial saturation
- dissolving metal reduction
- lindlar’s catalyst
in the hydrogenation of alkynes, in partial summation, what type of stereochemistry does a dissolving metal reduction product have?
anti addition (trans product)
in the hydrogenation of alkynes, in partial summation, what type of stereochemistry does a lindlar’s catalyst product have?
syn addition (cis products)
alkyne halogenation: product
tetrahalide
alkyne hydrohalogenation
alkynes react with some addition reagents IN EXCESS to produce double addition products
vinyl carbocations
the + is directly on the double bond and cannot easily rearrange
alkyne hydrohalogenation: product
markovnikov gem-dihalide
vinyl alcohols are uniquely reactive due to a phenomenon called _____________________
tautomerization
another name for the intermediate of a vinyl alcohol
enol
tautomerization
they reversibly swap the positions of a hydrogen and a pi bond
another name for the product of alkyne hydration
keto
alkyne hydroboration: product
aldehyde
alkyne hydroboration: mark or anti-mark OH
anti-mark OH
oxymercuration of alkynes: mark or anti-mark OH
mark
alkyne oxidative cleavage =
carboxylic acid and carbon dioxide
when naming molecule with an alkene and alkyne (enyne) where do you start numbering?
start neared to the first multiple bond, whether alkene and alkyne
how do you write the root when you have an alkene and alkyne within the molecule?
root-#-ene-#-yne
what is the most common alkyne?
H-C-(triple bond)-C-H
what occurs when an alkyne is catalyzed with a poisoned catalyst?
cannot continue to reduce so it will end with a double bond
when triple bonds have cleaving reactions what are the products?
carboxylic acids
when double bonds have cleaving reactions what are the products?
ketones
when alkynes react with KMnO4 (cold) what are the products?
double bonded O’s replace the triple bond
when alkynes react with KMnO4 (hot) what are the products?
double bonded O with OH to replace the double bond
