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