9d Flashcards
(21 cards)
many oxidative addition reactions with polarrrrr reactants are described as what
as sn2 reactions aka u in one concerted process
in the oxidative addition reaction,, what is the role of the metal
metal = nucleophile so it attacks the other things
aka polar: MeI and a square planar complex
metal attacs Me and kicks off I,, then the I comes in and attacks the complex
u get Me and I trans to one another
polar reagent =
sn2 oxidative addition
u get trans product
inversion of stereochemistry too
non polar reagent
concerted oxidative addition
u get cis product
no inversion of stereochemistry
describe a concerted oxidative addition
u get an orthogonal bond to the metal which breaks to give u u ligands and no inversion of stereochem
happens when u have a nonpolar reagent
describe an sn2 oxidative addition
happens when u have a polar reagent
inversion of stereochem
no orthogonal bond
metal attacks the electrophile
whats reductive elimination
the reverse of oxidative addition
aka ligands already on the metal join together and then kick themselves off
what do we go from to to when we have reductive elimination
we go from Oh to square planar
from 18e- to 16e-
when u have reductive elimination,, what must the 2 groups combining anf leaving be
they must be cis to one another
what is preserved when u have reductive elimination
u preserve the chirality of the groups
u have OA and RE but normally what happens
normally the reaction likes one of the ways and sticks with it
whats a 1,1- migratory insertion reaction
its when an X group is bonded to a metal,, aka its one bond away from the metal. aka directly bonded
then it migrates onto another group where its one bond away from the metal!! aka its the 2nd atom from the metal
from one bond away to an atom one bond away
what happens when u have a 1,1 migratory insertion reaction
u have 2 fewer electrons on the metal
which means youll have a vacant coordination site.
when u have 1,1 migratory insertion what happens
u form a vacant place,, that another ligand can go into
when u have a 1,1 migratory insertion,, how can u get different versions of the equilibrium
unbound ligand side = vaccum
bound ligand side = high CO pressure
how do we know its a 1,1 migratory insertion migration
bc its an Me moving onto a CO!!!
what a 1,2 insertion reaction
u have an X directly bonded to the metal and u have an n2 on the other side of the metal.
the n2 then splits into n1 chain and the X migrates onto the beta atommm.
so ur going from it being one bond away to being 2 bonds away
when u have a 1,2 insertion reaction,, what happens as a result
u decrease the corrdination number by1 and decrease the e- count by 2.
when u have an empty gap bc of a 1,2 insertion,, what can happen
u can add a ligand that will fill up the empty space
when u add an alkene for example,, this can polymerise
can the reverse of a 1,2 insertion happen
yes
u eliminate the X bonded to the beta atom,, and make it bond to the metal,, then u form the n2 // double bond again.
baeyman villiger: what groups move // migrate from C to O
remmeber u need the COO3 a peroxy carboxylic acidd!!!! so mcpba or RCO3H etc
H then big to smaller
H , 3, Ph or 2, etc etc.
