5. Carbon-Carbon bond synthesis Flashcards
nucleophiles are
electron pair donors
they react with atoms that don’t have enough electrons (electrophiles)
carbon carbon bond synthesis is used to
extend the carbon chain
cyanide ions (CN-) are nucleophiles because they contain
a negativley charged carbon atom
Cyanide ions (CN-) reac with carbon centres that have a
slight positive charge to create a new carbon-carbon bond
when a Cyanide ion reacts with a carbon the compound initially produced is a
nitrile
you can increase the length of a carbon chain by reacting
an organic compound that contains a slightly positive carbon centre with a cyanide reagent such as potassium cyanide KCN, sodium cyanide NaCN or hydrogen cyanide HCN
cyanide ions CN- react with haloalkanes by what reaction
nucleophillic substitution
why is the carbon electron deficient (electrophile) in a haloalkane
contain polar carbon-halogen bond
halogen generally more elctronegative than the carbon
conditins needed for cyanide ions to react with haloalkanes forming a nitrile
reflux haloalkane with pottassium/sodium cyanide in ethanol
cyanide ions will react with haloalkane by nucleophilic substitution to form a nitrile (C2H5CN)
how do you form a hydroxynitrile? RRCOHCN
mic a carbonyl compound (aldehyde/ketone) with hydrogen cyanide
cyanide ion reacts with positiv carbon centre to form a hydroxynitrile
nucleophillic addition
why is it easy to convert a nitrile into a new functional group
nitrile groups are very reactive
nitriles can be reduced to form
prmary amines
how to reduce a nitrile to a primary amine
use lithium aluminium hydride LiAlH4 (strong reducing agent)
followed by dilute acid
hydroxynitriles can be reduced to form
primary amine
how to reduce hydroxynitrile to a primary amine
use lithium aluminium hydride LiAlH4 (strong reducing agent)
followed by dilute acid
other reducing agents to reduce a nitrile or hydroxynitrile into a primary amine (other than lithium aluminium hydride )
sodium metal and ethanol
in industry why aren’t LiAlH4 and sodium not used to reduce nitriles and hydroxynitriles (forming primary amines)
too expensive
in indusrty what is used to reduce nitriles
hydrogen gas
metal catalyst (platinum or nickel)
high temperature and pressure (this is called catalytic hydrogenation)
nitriles can be hydrolysed to form
carboxcylic acids
how to hydrolyse a nitrile into a carboxylic acid
reflux nitrile in dilute HCl
what kind of reaction forms carbon-carbon bonds with benzene rings
friedel-crafts reaction
how to form a carbon-carbon bond between a benzene ring and a halogenated carbon
reflux benzene with a halogen carrier (e.g. AlCl3)
and either a haloalkane or an acyl chloride
