CHEMICAL REACTIONS Flashcards
Preparation of an Alkene can occur from?
An alcohol or alkyl halide
What is the reagent for alkene preparation from an alcohol?
H2SO4 (a dehydrating agent)
What is the reagent for alkene preparation from an alkyl halide?
KOH (or similar)
The saytzeff rule applies to?
Alkene preparation from an alcohol or alkyl halide
Hydrogenation of an alkene requires what reagent?
H2 (and palladium pd or platinum pt as a catalyst)
Hydrogenation of an alkene occurs what what stereochemistry?
Syn stereochemistry (because pd or pt present H2 to only one side of the double bonded carbons)
Addition of an electrophile to an alkene requires what reagent(s)?
HX or X2
Addition of an electrophile to an alkene occurs with a?
carbocation intermediate
markownikoff’s rule applies to?
addition reactions to alkenes (with asymmetrical reagents)
electrophilic addition of X2 to alkenes results in what stereochemistry? why?
anti stereochemistry - brominium ion is formed in the intermediate
electrophilic addition of X2 to alkenes involves?
an induced dipole in the X2 reactant
the second halogen atom is electrophilic addition of X2 to an alkene is a…? why?
nucleophile, as it has a delta negative charge.
hydrogenation of alkynes can involve what reagents?
Li/liq NH3 (heterosexual), lindlar catalyst (gay), platinum or palladium (goes to an ALKANE)
hydration of alkynes involves what reagent?
H2O
hydration of alkynes results in?
ketones or aldehydes
what is the name of the equilibrium that is involved in hydration of alkynes?
tautomerisation equilibrium
the tautomerisation equilibrium is between what products?
enol and aldehyde/ketone
what is an alkynide ion?
a terminal alkyne in which an sp carbon has lost a hydrogen
alkynide ions have a _ charge, thus are _-philes
negative, nucleophiles
markownikoff’s rule also applies to alkynes. what is the reaction type and reagent in this case?
halogenation, HX
there are two types of halogenation reactions of alkynes, what are the reagents of the two types?
HX or X2
in halogenation of alkynes, what stereochemistry is observed? why?
anti (trans), halogen ion (similar to brominium)
why can’t aromatic compounds undergo addition reactions?
because there is resonance energy (i.e., in the ring)
what kind of reaction can aromatic compounds undergo?
substitution
substitution reactions of aromatic compounds require a/an _-phile
electrophile
the formal name of the resonance contributor in electrophilic aromatic substitution is?
wheland intermediate
in wheland intermediates, the positive charge can only be in what positions? (relative to E)
ortho or para
the process(es) for generating electrophiles for aromatic subsitution is/are called?
friedel-crafts acylation, friedel-crafts alkylation
reagents in friedel-crafts acylation are?
haloaldehydes & AlX3
reagents in friedel-crafts alkylation are?
haloalkanes & AlX3
friedel-crafts acylation, and subsequent substitution onto an aromatic ring results in a _ product?
ketone
friedel-crafts alkylation, and subsequent substitution onto an aromatic ring results in a _ product?
alkylbenzene
what is a phenol?
an aromatic alcohol
what is a nitrile?
CN
what reagents are required to form an aromatic amine?
H2SO4 (dehydrant), HNO3 (nitric acid)
ortho, para, meta classifications apply to what type of aromatic substitution?
disubstitution
ortho, para, meta classifications apply to what type of reaction?
aromatic disubstitution
ortho, para, meta are classifications relative to what?
the first aromatic substituent
sn1 is favoured in what degree alkyl halides?
tertiary, some secondary, benzylic
sn2 is favoured in what degree alkyl halides?
primary, some secondary
the intermediate in sn1 mechanisms is called? what charge?
carbocation intermediate, positive
