lecture 3 Flashcards
🌷how is DMDO made
acetone + KHSO5
gives DMDO
name dmdo
di methyl dioxirane
what is KHSO5
potassium
peroxy mono sulfate
what is KHSO5 used for🌷
used to react with acetone to give dmdo
highlight the 2 step process to making epoxiranes🌷
alkene + Br2 and H2O (bromonium ion then open it using H2O)
bromonium ion + NaOH (removes most acidic H)
arrow kicks off Br using O- on the alcoholate
epoxilate is made with NaBr
in the reaction of making epoxirane, what is used to ring open the bromonium ion
H2O
in the epoxirane, what is used to remove the most acidic H
NaOH
describe an alcoholate🌷
O-
with a halogen on adjacent C
how is an epoxide made from the alcoholate
the - charge is used to kick off the bromine (good LG)
and forms an epoxide
what is a toluene
benzene with CH3 attached
how is an epoxide made from a toluene🌷
liver oxidase and O2
McBPA cannot react with aromatics
🌷 cyclohexane epoxide with HNMe2
N: attacks the other side of the epoxide
the NHMe ring opens the epoxide
the product is trans (one dashed one wedged) the O from the epoxide grabs a H. NHMe loses a H to make the N neutral
asymmetric epoxide with NaOMe and MeOH (stereospecific ring opening reaction 1 ) BASE CATALYSED EPOXIDE RING OPENING🌷
the O- in NaOMe attacks the less hindered C and ring opens the epoxide
the O- epoxide grabs the H in HOMe
this gives an OH and an COMe alkene
asymmetric epoxide with H+ and MeOH ( 2nd stereospecific ring opening reaction ) ACID CATALYSED EPOXIDE RING OPENING🌷
the epoxide is placed in an acidic environment (lots of H+) + is protonated
the O: attacks a H+ and forms an alcohol epoxide (still a ring)
then the MeOH ring opens it at the most stable section. gives an OH and OMe alkene
🌷what do the reaction conditions of epoxides determine
determine what carbon will be attacked to ring open
normal asymmetric epoxide and
NaO-Me,, which epoxide C will be attacked🌷
the most accessible one
the O- attacks the least hindered epoxide C
normal asymmetric carbon and H+ aka an acidic environment🌷
the lone pairs on the O attack the protons leading to an epoxide but the O is bonded to a H (alcohol)
the MeOH then ring opens it at the most stable CC+
describe what a epichlorohydrin looks like🌷
epoxide with a methyl tail and a Cl at the end
name a bad way of making epichlorohydrin
alkyl chloride
and
McPBA
🌷why is making epichlorohydrin using alkyl chloride and mcPBA bad
it makes more mCBA than epichlorohydrin
more side product than desired product
how else can epichlorohydrin be made
alkyl chloride
HOCl (hypochlorus acid)
NaOH
steps of making epichlorohydrin using NaOH, HOCl and and alkyl chloride🌷
alkyl chloride + Cl+
makes a chloronium ion
OH- attacks this and ring opens it
NaOH removes the most acidic proton
a epichlorohydrin is made
steps of making epichlorohydrin using glycerine
E with OH at each end🌷
glycerine + HCl
H+ protonates the groups
Cl- attacks the carbons and removes the H2O leaving groups
its treated with NaOH to make a epichlorohydrin
3 ways to make an epoxide🌷
alkene + mcpba
alkene + dmdo
alkene + Br2 + H2O + NaOH
alkene + mcpba
epoxide
mcba
alkene + dmdo
epoxide
acetone
alkene + Br2 + H2O + NaOH
epoxide + NaBr
alkene
bromohydrin (OH and Br)
alcoholate (O- and Br)
then Br is kicked off bc its a good leaving group
🌷base catalysed ring opening reaction
epoxide + Na OMe + MeOH
O on epoxide = weak LG,, it must first be attacked by the nucleophile in order for the MeOH to attack.
the OMe will attack the least hindered carbon of the epoxide
🌷acid catalysed ring opening reaction
there is H+ present which allows O of epoxide to be protonated forming a good LG (OH),, this then doesnt need a nuc and so MeOH can attack the most stable c on epoxide
acid catalysed ring opening🌷
most stable cc+
base catalysed ring opening reactio🌷n
least hindered carbon
