AIKyl halides
and
A ryl halides
Halo alkanes and
halo arenes)
AKylhalide.
AlKyl halide.
AlKane
R-H
He-x
cHy
+X
Cmethane )
Cmethy! halile)
(X = -F, -cl,
-8Y
o
-)
Aryl halide:
Aryl halide.
Arene
CHalo arene)
aromate cumpo nd
eg:
(Benzene)
++ X
=
(halo be nze ne)
(or
-F, -cl, -Br
-)
2
Classifi caion .
Aryl halides
&
ides
hal
lIKgl
A
Tri hal o
Dihalo alkane
Mono halo alkane
alkane.
HCcH-CH,
eq:
He-X
eg:
eg:
eg:
Compounds Centaining
Compounds Cuntaining se
Sp
bord
Alyl halides (R
Allylic
halides
Beylf
halides
eg:
çHX
He-cHx
C-X bond.
Vinylic
Aryl
halides
halide
eg:
eg:
He=cH-X
ahe
chlro
Tetra
chloride
tetra Carben
chlorofu
Trichloro
Dichloro
chloride Methylene
ccly
CHclg
chioride
8)
)
CHcl,
=CH-c
thene chloro
bromide
-Bromo
H,C
S)
Ving)
propy1
4
Iso
BY
bromide n-PropPy)
1-Browo
.
BY
He-cH-Bv
8romo
bromide
Ethyl
bromide Methyl
Broro
e
und ompo
me
hame
IUPAC
mnon
kane
He-cHX
C
Co
al
Halo
Name:
TUPAC
CHyX,
formula :
CnHn
halide) (AIKsl
General
Nomenclatuhe:
3
Basic topics:
Ty Pes 0f solvents.
Nucleophilicity Vs. Basieity
Leaving
Types of
gYoup.
Solvents :
Solvent
Non-polar
Polay
polar
polar
aproic
protic
solve nt
(a) Polar
Polay rotic Solvent:
One
A protHe Solvent
protons CHt)
N-H
H,0,
wsually
+hat has
acidic
in the fum of
3roups.
HC-oH, GHoH, H-CooH, He-cooH NH,
H-5-Nformamide) ete
Di ele cthie constant (E):
H-G-äH
Note
5
111
H,o
wth
Solvents
more
values
dielectic cnstant (E)
moRe polar
are
Polar aprotic Solvent:
howe
but donot
natue,
has polar
Solvent
This
0-H or) N-H
|Solvent with out
acidie proten H+}
grou.
Acetene
DMSO
Dimethyl Sulphoxide)
fermamide)
Dimethy
DMF (
(Dimethyl acetamide)
DMA
Aceto nitile
Slfolahe
-NCH
S9,, Hc-NO,,
6
and
HMPA
(Hexamethyl phospho ra mide
N
pNCH
H
Non-polar solvent:
(6)
u)
moment
dipole
The net
ane.
I, 4- DioX
ccly,
Benzene
Nucleophilicity Vs. Basicity
Nucleophile:
A nucleophile
seeks
Base :
iS a reagent
positve
Electron pair donov
is
center.
Base "
Hhat
Nucleophilicity :
electrophilie
attack
protn(H+)
species to
Casbon
0f the
The a bility
Basicity :
the
of
ability
the
to gemo ve
Spe cies
acid
frem
:OH
C-OH.
+
:OH
CNucleophile)
Case-I
H,o +
A
H-A
:ÞH
Case-T:
(acid)
CBase)
defined by +he
Nucleophilicity
electophilic Casbor atm
Nott:
rate
Censtant
(k)
equilibriwm
the
which
attack on
dt
rate
reflected
which is
while Basicity
Constant
(K).
fer
y
is defined by
ab straeting
8
Nuclephilicty :
k
-X
Nu
c-Nu
Crate canstaot)
t
Basicity:
B-H
+
A
H
Ceguilibnum
Censtant)
(au)
Cbase)
Basi cty
and
nucleophiliaty
are
2
diffeut
poprhes .
Note:
kinetie propeaty
Nuckophili aty
basiaty
15
a
+hermodynamic
shee as
prputy
A
Seagents :
of
O
re lathve nucleophilicty
determining the
Factors
2) polarisa bility
Basicity
(3) Solvation
Rasicity:
In periods
bastcty
Loth
and
nucleophilicity
decreases
F:
eg G):
OH >F
>
NH
JCH, >
basi aty &
ovder
ccveasing
nucle ophi licty
cHt
CHy
Note
(vy
baseJ
HE
(stnq aad)
C - less e
Note:
bour decd.
i-e,
Chg
So,
(: Bransted
(streng
weak a ad )
Cueak base)
So,
lectro neqat ve .
donat
more nscleophilic
Louwry
lone pair
wheve
as
Ione paur loosel
east ly
So, it is
Jess
nucleophi lic
e lement
: PH,
sit3
Tn hroups,
but
decreaseS
hasiit
bous ded.
>
polarisasility:
2
more electonegative
sthengly
|one pauY
So,
egi):
F is
be cause
nucleoplicty
inreaSes .
T.
dcreasing ordY;
basiaty
Co-tcd)
HI
(stangacd)
Nucleophliity decreasng
CS-Base.
Cweak base
order:
V
H
I
big size.
attacls
at
mre polausaion.
e hctophi 'c
Eosiy
Centre.
I
F
I
|ess
m ere
polai satta.
oH, SH,
eg:
nucesphilicity
points
to
pola'satien
TeH
Se H,
iveasing ovder:
Remember.
nuceophiles
Bases are
thas theiY
better
Conjugate acds
SH > H, S:
ÖH > H,0;
(b)
For Same
Strng
eg:
donatn9
otem,
strag base
acts
as
nucleophile.
HCOo
< Hc-coo
ph-o
> R-oH
HcooH > Hc-cooH > ph-oH
CwA)
Cacidic natue)
(S4)
Hcoo
Cw-8)
< Hc-coo
12
Ex ce ptio :
H,C-CHo,
(ethoide
ion)
Ca-butexide ion)
hon 1e
more acdic
HC-CH-oH
()
He-cH-0
is less
basic
than
nucleopilic
but
H-CH-o
due to
stesic
than
m re
hindran Ce
in
Solvaion ;
Nucleophiliaty de pends
nucleophilicity
de cveasing
natue d
solvent.
order :
Ln
water)
ie;Cpotic solvent)
I n acetne
ie;
aprohc Solvent)
be Conined.
13
Reason:
In polh pvotic Solvent
Srnal|
Sol vaton
more
So, nckophiliity
ion
takes p lace
decYeases.
less
e
e nucleophilic)
(Inwaey)
more
nucleophil'e)
(In water)
apotic Solvent,
Ln pola
tales place
does not
de cided by
change
choge
density
nucesphilic.
thon
antan)
ions
o
solvatian
nucleophil'aty 's
Nouw,
F ha
den sity
So,
more
more
The
overall
nucleoplity dcreasing order is:
In wcer
polasprotic solvent)
strong nuclkophiles.
R-s:
ph-s:
Et, P> sH > I >
CN > Et, N > Oet >
moderate nudeophiles:
ph-o
we
eak
nuckophiles:
NHg > He-sct
Et, NH >
Groups.
>cI
> BY > II
tendenay
orcerdecreasing
Leawtng
:
ard Cstrong
base) Cwweak
+I
cd) (weaka
base) Cstng
d0o g
Leawing
ae
weak
bases
: Note
oflity stabi
Bro)
bondd
wing.
Leaing
ability
ot
a in
()
Strengh,
d
R-L
R-L
by, influencecl
Leawing
Groyp
of es
the
G-bond
.
growpfunctioncl
ís
The
eliminatcol
witth
is Group
+he
Leaving
at +h
roup: Leavin9
Resonance stabi lised
Note:
nias
16
are
Leawing
Good
:0:
o=S0
(Tritlatt ion)
(Tritluoro methy |
Cmesylate)
CTosylate)
Sulfonate)
(or)
or (methy)
Sulforate.
p-Toluene
sutfonate)
[ors)
The
Leauig
tendenay
>
Tosy late
Triflat> p-ntto
decveasing ordeY;
I
> mesylate
>
(oTs)
benzene
Sul fente
V
ot
Nott:
NH
CN, ott,
.
por
Leawing
roups
are
(:: strong base s).
Cbad)
Note
They
Leaves
as
sespecivey
F
SH,
CN, oH, R-o, NH
Halogen Containing
()
()
()
AtKy) halides
R-)
Argl hali des
Cph-)
Compound s:
Grignard seogents
chloroferm
(R-mg)
(CHcla)
AlKyl Halides :
H
chemical proertes
preparation
physical
propertes.
(3
chemical propries.
Nucleophilic Substtutian ( (S2
Su,
(Theluding
Eliminatics
NGP)
seacticS:
mísce I\aneous
Other
Su.
Seacions.
G) Nucleophilic
Guhsttution
-X
Nu
nucleophile
Here
reactioms:
)
Canbe replaced by
hucleophileNue).
anothe
Leawes
General
reacion:
RX
(AIKy halide)
This
Suachon
different
two
as
Nu
Coucleophile)
has
been found
to pro Ceed by
mechaniSns,
and
i-ej
Substtutn
bimoleClan nucleophille
nucleo
thuclephiic
uni molealas Substtuhi on.
an
9
(a)
S.,2
CBimoleculas nucleophelre subst tution):
chaateistics
It
2
Seactior:
SN2
d
Single Step heacti on
i
suhstrate:
Natwi e d
towards
Reactuity
CUncerted reactien.
i-e
decreasing oder is
SN2
> 2 R-x >
3 R-x
(No SN
Natwie d Solvent:
aprotic
Polas
|iKe
Solvent
DMSO
DME,
used
4
Natue d
nucleophile:
streng nucleophile (Base)
Can be
Nature
Good
wit
high
Con Centrati
used
Leaving
Leaving
roup:
roup fowowrs
EWG better for sn2, better than super primary
SN2
ten den ay
Leawing
ordes:
de creasing
R-Br
20
R-cl> R-F:
heacivity :
R-Nu
Rate
d
[R-CNü
k
=
Rate
Rate d
depends
Auoction
nucleaphile (Nuy
as wel| as
Reactansts
one Sep
willbe
Cenverted
Con entratin
RX
Conatration
rdes
& follows
himole Culas Jeaction
in
bott
tnto
So
itis
1inetiCs.
products
penta valented Trcnsitten
+hrough
Stat.
Stereo
T
+he
chemisty :
al kyl halide
9iven
Cophcal actue)
+hen
inversion product.
the
(R)
is
pre duuct is
chiral
walden -
Suactant
4hes
eg G):
prvduct
has
HC-cl
+
has
R
21
Cenfguhaton,
vice -Veisa.
Con figatn
He-oH +
c
Mech:
--cl
: OH
+
plarar Transitn
State
HO
H
CcHcD'CoH'
k
Rate =
oH
at
attackS
antiondi ng
at
Cab orn
ie,
orsital dt
CL.
\H
(anti-bending
orsitau)
The in comi ng nucleophile ot)
Causing
He-cI
with
while
byeak
ferming a
step
the bcnd
pvogresSes,
C-OH
between
Casbe
Leaving
in
roup
a Singe
4s the
betwen
weakens formig
(c)
TS. is
transificn stote.
plonas
the
Caben is
cl
C
As
atem
Same
way
inside out
an
when
Thiy pro @ss is
Confguatn
+he
inverts
attack
as
hysridsecd
(TYansikan state)
happens,
wndr
Sp
H
H
+his
eactcy
Cab on
and
b cnd
atem
t
bond" These
OH
Starts forming, while
whilk the
and
bond
i's fermed.
intemeddiate
and
C-cl
Simdtah eously
take place
pro Cesses
two
+he
new
22
intera cts
umbrela
Caught
called
much
in
is
+he
turned
Strong wind.
INVersion
d
Configustcn
+he
(orj
opical
Case o
Note:
produt
acive
Inversion
al lkyl haide,
Inversi cn poduct
Calle
wal den
product
R
Tf
Ho-c
i t is
(R)
then
(s)
4hen
eg 6i);
23
R
(5)
(R)
+
Cts
(s)
cg ) 3
3r)1
H)
(CHs
2
(R)
": lCIP-Rules
(s)
244
mech :
CI
S
S
+ö:
-BY
HO --
GH
H
TS
ctt!
Ho-not
OH
egi ) .
+ BY.
H
OH
(5)
(e
Ctrans)
(cis)
Note :
TranS
cis
(or)
TrnS
also
Censi
deled
as
InverSi on
Relatve
S
eactions
rates co
2
ot
al lyy
25
haldes
eactions:
Ccompouund
Relive ate
30
He-x
He-cHx
G)
O.o3
)
-X
(3)
due to
rat
elative
Note:
steic hindrance.
H
wont
Hö:
approach
due to
steic crowding.
HC
CH3
knued
---
be(T
Hc-T
C,H-0-ct
I
):
eg
+
).bondC-cl
is bend
than stnges
C-oH
sea
ctton)
co-ordndes
+cT.
+cr)
(evotteA
mic
Reacticn
products.C
CoH
+ot)
(CHcl
Reactonts
Enengy
Ea
Transitien
state
HO---cH-cl
t{C-cI
eg:
Grapb:
6
(b)
S
Reactons(Uni moleculah nudeophilic
Substitti on):
SN1
characteistics o
Tt is
multi -Step
C
eacioy ?
/Gereally 3 step
Seacion
non- ConCerted)
Sonl
under go
first step,
c
cleawage
heterytic
Solvent
and
to
in presene
plana
give
polo protic
his is
Ccouho Coti c
slo w
step
Sewehsibl
H, O:
Csolvent)
Cbo
ten
(S]ow)
1
ow
we Kn
steP,
hat
rate d
multi-Ste p
aea' dapends
A0acians
in
One
eactant
ie
rate d (R-]
Ratk = k[R
slo
slow
in voled in
R
I t is
Aua
imokalaty
follows
order
KinetCs.
step
21
H,o:
to gve
alcdhol,
ohich
alcohol, oich
e
These two steps
al cohol.
wndei go
step to
by tö:
ceprotenation
4
attacks on
pvotonated
28
Casibo Cotton
ive
fast steps.
Substrate :
Natue c
ohich ferms
The
SN
maore
stable
rechanis m.
Carbo Coti on
the Seactuity c
order
decreasing
3
is :
He-x.
V
R-X
Natuse d
No SN1 sea
solvent:
polar protic soluents
Can be
SN 1 e a
towaids
Rx
(( Ke
be Cause
useds
transifen state
decveaseS.
and
(or)
Solvaticn
leading to the
+he
CarboCati n
H0
+hus
So, rate d
+he
alcohol
stabilise s
intermediate
acivation enisy
Jeaction
increa Ses.
6
Natse c
weak nuceophile
Cas be used .
eliminat on
stong
hucleophile favo s
Nate dt
Leawing
group:
Leaving Group fauouhed
Good
Suactuity
in
SN
Seactic
orden is:
decreasing
R-I
eacti on.
solvolysis
Called
i5
acts as
Solvent
ín which
Seaction,
nucleopbile
The
rathes
Substittion
than
the
(Genealy solveot itself
weak nuclkephile
acts as
24
ncleophile :
R-BY
R-cl
EDG favorable for SN1
s t ochemistny:
Ið the
the
is
alkyi halide
product is
Some
inverSion.
opi Ca active
Racemic mixtwe
then
along with
30
abo Cath'cn
StabJe
Cabo Cati cn
may
hearange
er)
Wag ner -
Called
Seasrangement .
used.
Can also be
Ag No,
Catalyst
eg G):
shift
I,2- H
This is
by I,2- CH¡ shift.
meerwin
mre Stable
Convet into
eithei by
CaboCati on
ie;a less
Ct
(3-buty
alcohol).
(3)
mech: step):
Slow
+ : i:
H,o:
(plana
Step G):
3-Casbo Catian).
fast
cH3
H
(Protenatecl alcchol)
ct3
StepGi):
cty
+
H,o:
fast
-ot
+
H,0.
31
Note :
nd
eactart and
Ið
Seactant
and
Confquations,
produ ct
he
then
Corfq u aticn,
product
bott hawe sae
Retention product
is
and product
rodu ct
thes -he
hawe
is
diffeest
Called
LNveYSfcn
preduct.
Raactaot
’product
(R)
if,
(s)
(S)
C
Retention pvodect)
C
p dect
Roactant
(S)
(R)
(R)
Inversion pode ct)
(S)
if,
equi mola
mictuse o
Raamic
Callkd
invesston
mixtue
Setentcr
lov)
Racemic modisaticn
32
Note: In
SN
+he
the qreates
m ore
he
+he
Stalble
more
+he
-the pvo per*on
is
Carbo Coen
racemiSatini-e;
d
Racemic mixtute
tte qreten ís
wcleophilic +he solvent,
mae
invusi on
poputin
+ Ho-C,
(P
Ph
Ph
(5)
(R)
(R)
Rutertiony
517.
Racmic
44 + 44
mixtue
q27.
RaemiL mitu =q9/.
IveSion
mech:
2.
slow
-c
step ) :
ph
Ph
Cplana
33
stepi) :
Ph
oH
Ho-c
pb
ph
(Retention)
CInversin
cH3
eglii):
-c
+
Ho
Ho
(R)
(R)
(Retention)
(s)
CInvesi
(()
Ralemic mictuse
17+4 = 34.
33-17 = 66 /,
Ihvehsin
Note
(
CH3
ph-ct-CH
ph-ccl
(33)
(2-beny1)
-CI
CH -C)
(2-ky1)
we knc
more
thet,
Stabk
the
Carbo atton,
Raamie mista)
eate is the
c
ase
Case
So,
ph-cH-cl
d
487. Ra amiSatier
we got
H,G -cH-c
Case d
whele as
34
CRacemc mixte
we got
341. Raami
-Saticn:
(Raenic
miztee
ph-cH-CH,
> H,C-cH-cH
Stasilit
Reason:
mere
two
steps
Carbo Cation,
fermation t
|st step i-e,
the
ordes:
invalved
R + Br
R-BY
Br
RBY
R-Br
lnimate
jo- pair
Eree
Solvent
ons
Seporated
ion paiY
Inase d
afte
Carbo Cao,
more Stalk
fernati n ct
cn.
free Casbo Catt
more"
is
aton)
mishse Qace misalmost
eumolai
(ie,
mitwe
the
lovesian
Retentian 4
nuckophik a ttads
So .
d
ae nic
35
leeS Stask
in Case d
but
huceopkile
at
attackS
iS
invessian
the
Casbo Cati cn,
step
intimate an
i on pas
grete +han
hetenti
So,
(less favoubud)
(more
faveused)
Retentin Cminor)
Invasion(majar)
egid:
CH3
Ho:
CH3
-CHCH-cl
:6H
(wmte mechanism).
CH3
CHty
egliv):
H,o:
-CH-cl
Hc-Hy-cty
36
:OH
cHy
slow
-CH-CHcl
ech: stp):
CH3
Hc-cH-CH-cH + cT
(a)
Rearrngement
on
f Carbo Coti
CH3
J,2-H -
CHCH
2
Hf
shift
1
- -cH,-cH
(wagner- Meewis eaangement)
fast
step): HC--cHty-cty
-cth-CHg
+ H0:
\
H
step i :
Hc-cH-cly
+ Ha.
fast,
H.
H,o:
Eg :
mech:
slow
StepC):
,-CH,shift
(Ring eponsien)
34
stepli):
fast,
-+*
Note:
SN
Rate d
Can be
in Crea sed by
Hyc+ tgNo
-¢cl
Ctty
using
Cataly st
+ Agcl
(Pet)
Moist Ag2O also at normal temperature
Graph:
TS-1
T-S-2
Ic-ç-cit
Ts-3
Eneasy
Reacior
co-rdinates
(To be Continued..)
AIKy fluerides
NOte
toweve,
Casbo cation
heactive
33
touwand s
bond is vuy Stren g
C-F
beCause
SN1
least
ahe
is generted
by treating
witth
R-F
R-F + SbFs
Facrs favouring
SN1
Versus
SN2 Seactiems:
SN
SN
Pactr
3>2
|He-x >> i>2
Substrate
weak nuceophle
Nucleophile
strny nuceop hil
heeded
is
OK
polan
solvent
Polan aproe Soluent
DMF, DMSo, Acetene
ete)
Profc Solve
R-cooH ete)
9ood ohe seguie
Leawing
Group
good one
hequinecd.
I>Brscl>f
I>Br>l>F
Low Reackuity
Viny! and
t
ayl hali des
as
S
botth
H,C
ae
39
aryl halides
least eacive
towasd s
SN2
well as
HCCH=ct:
=CHCI:
Cvinylchlovide)
(chlorobenzene)
Lo both
ayl balides
viny and
double
chahactes
bend
due to
wont break
has
C-cl
Afte
bend
breaking
Casbo Cations
C-cl bend
also,
easily
they fom
H,c=CH,
Seacte touahcls
They ase least
least stable
SN
and sN:
tigh
aly | and
eactivity d
benzy
haides a
and benzy
Ally
as
SN
haides
tosids
hea ctive
more
well as
ahe
They
fematen d
mare
de to
SN1
Seactve towads
)
Carbo Cations.
Stabk
=cH-CH
H,c=cH-CHy-cl
CosboCaien)
(Ally) cbleride
CHe
cH-c|
CBeneyl CanboCatiovn)
CBeneyl chloride)
eactive
are
double bend
Stat
Coyugatien
attack.
wells
SNtoansite
the
p-rbital
by
atm
Stabilizes
the
because
as
+o wands
at
tHhe
caben
wwith
inreases
this
SN
rate
under
Joweing
evehy
baiev.
Hc = CH-CH-c|
+OH
Hc=cH-cH-oH
OH
tere,
H,C =cH-CH
cl
OH
CH
H
,6
C|
Br
Note:
3 R
these
two ae
halides
haides but
kud
kyt
3 ad
the
ate dd
s
very leSS.
vey
Br
-6
Relative
Ratt
1
Bredts rule
accommodate
So,
10
A bridge- head
Calbo Catcs
is
Cabo Cat'on fonatn
Cab on
Sihce
it
is
not poSSible.
non-planas.
Re lative
42
al kyt halides
Seactiities co
SN2
Phct-cl >
H,C =GH- CH Cl
> Hccl > HeCHy-c|
Hc-cl
-c)
(no SN)
(3)
ctities
Relatie
The
will
o
fums
dkyt halide which
fawouh
SN1 Aeact'cn:
lK4 halides
al
mere
Stable
ConboCatton
S1
He-ctg-ccl > phb-ph
C3-benzy)
Back bonding
ph-cH-ph
(-beney)
cIs =CH-ci-cl
(-ber)
>Hc-cl
((-ally)
He-cH-cl
Ca'-aky)
> Hc-cl.
eactive towards S 1 .
43
dkyt
SN1
twad
Seactve
moe
following
of the
L0: which
halice
eaction 9
IsC=CH-cis&r
(B) phcih- Br
(p)
Ans
and
e ,it iG
D).
I
is
Since )
SN2
actcn,
24:
in(Yeasecl
+i
by
how
increased by
+he
then,
nany
nucop hik
Conanrahn
rate d
+he
3 times
in Creased by
conantrachcn e
+he
es
+hau
rou
gord Leawing
times ?
k[R- [ .
Rate
For e9:
2
rate d
eactn
imes"
by
increasec
actn
Internal nucleophilie
Reacion
Substtution)
Suhstrcte
+he
attacks
Sest c
the
detaches
Suactart )
the
leasing
itseyf
qrouf.
(R)- 2- butano l
onvesion of
eg:
Lecwing
pat
process
this
rouf which
(R-chloro
to
Solvert
-polas So
butane
with
and
Socl
base
ab sen ce
R-cl
RH
+
Hcl
+ Socl,
Ghiong chloride)
Fomation of
mech:
+ So,
internediate
chloroSulite
Step):
esteY:
R--
-cl
++ t+cl
A IKy l chloro-
Sul fite).
chlro Suite eter
Lon-paúr:
disso i ates to
intimode
5
RoS-cl
m
(intmate ien
fermatten
stepli);
with
The cl,
frem
R
the
pair).
alkH chleride:
pair d
+he
he proeuct
es,
anion
of +he
Same Side
of the
atta ckS
Casso oation.
Complete
So,
s0,
R-cl
R
chemisty
steico chenisty
d sN
The product
iS
Com plete
Retenton prdct
-cl + So,
SOcl
eg
(thiony)
Chloride)
H
Ch ts
-2- butano!
-chco
butane)
446
Tn pe Sen d
Note o
PYridne,
Invesion product.
product
he
Such as
2-amine
to frm
Co-erdinoetes
Ptridine
do chlortde
hy
Pyricine
nucerphile
& the
Freu nuceophile).
from
chloros lfte
mechaniSm
an efective
ester
attadcs
Now
backside
via
Invusien pweluct"
to
the Seacthn e
Socl
dcohols (R-oH)
Pyridine
Knon as
Pratis
Dar zen's
in preSence Of
proCecute"
cH3
-öH
(R)
+S0c
(s)
(Invasion)
rech:
+
-OH
-B-c
OS
CHs
+
SN
-cl
e
cl-c
baclkside attack)
+ So, tcu
pantcipatian):
goup
(Neighbousig
NGP:
functin Group
Secerd
Sheactat
moleade.
Substootal
0f
tis
Know
as
pre sent
fr
4he
Neighbouing
irernal
pattiapatico
displace ment
Group
CNaP
inthe
heie is
Cases,
evidece
roup
is
procesSes
)
pati cipatics,
Subsitution
NGP
thouSand
ae
fft Step
Group
2nd
and
4roup
Cyclic
etena
csplacs the
Origina
its
posiion
as
as
N
as
neghbosing group.
nigh bouting
neighboing
nughbouting
back sie
back to
Retent
The final prrduct is
Preduct"
as
by a
Goes
neghbouiny
he
attack -
Broup
inteemediccte.
nucleophile
he
hboung
actng
Pushes 0ut the
forms a
the
Cente rs.
eacticns.
nuckophi le
ars intenal
because
Seactve
neighbouing
+he
than the
Aeactins
two
Snvoles
N-G-P.
invowe the
faster
0f the
Proximity
of the
leawing
t mes
intemoleala
Cor pasable
Ih the
that
Aeactrens
qroup.
rou.
roup.
nghboLAing
Oyge
9
4roup
cly
:ÖH
(2)
(
CRotentien
meco:
Intramakalas
SN
Stp:
"ct3
(R)
Intumoeadar
+:0H
SN
stp).
(5)
(e)
(Retenton
5o
Summary :
Oves all
S.NO.
Subsitutte
geacti on
stereo chemisty.
Invesion
SN
Radmic mite along
SN1
witt
Some Irversron.
Retenton
SNI
ToveYSion
Pridine.
Retent
N GP.
Two SN
heactions)
stePO:Inversin
Invexsien
Step:
Overa):
Retenh'en
Contd
Eliminaton
Reaci ons
halogenation
hycoo
de
dergo
un
alides
Avel h
AKyl
to gi ve
base
in preence o
CH)
al kenes.
Base
(H
This
has
Seactior
() E1.
(4) E2
Bimolealas
Reactin:
chaacteisics
(i)
mechanis mS.
2
E
Reaction;
(Concerted) Seactn
seac
Single Step
is
Joactiuity d
eliminatio):
R-x:
3
R
>
and
Gi)
tares plac thvoug h
This
transition
R
anti- o-planar -
Stte
+ Base
A(Kene
Rae d [R-Base
Rote = k [e-[Basey
J+
followS
is bimokala
Soa tie
nl ordey Kinetcs
Steng base
unhinded
(
Sayt zeff's
prduct
lie
52
NaoEt,
pvedo vminant prodct
iS
Kene)
(mcre stabk AI
with
(vi)
bhase like
Steng
(bulky)
hindud
pofassium
Hofmahn pro du ct
2-budoxide
(les/least staslk alkane)
is predeminant product.
The given R ,
should
east
Centain
one
B-hy dsuwgen atom
G Ho H
kifi)
solvent,
Can he used.
Solvent
eg3
NaoEt
CH
CH-CH
HccH=CH -CH,
CtoH
(meStasle
(Sayt zeff produc)
CMaoy
HC=CH-CHy-cH
Cmino)
Cless Stasle) (Hofmann
prsdu ct)
53
ich:
E+D:
HC-CHYCHCH
Et9:.
H
Br
1
Br
Tis \
co-fplanen
(aot
HC-CHt=CH-ct
CMajor)
+
EtoH
++Br.
NOTE:
For
1st
more
year
examplks
AlKenes
please Tefey
topic.
AlKeres by
of
atin
Prepas
dehy doo halgenat'on.
E1
It
hon- con tertedl)
steps
2
is
54
E Suacton
characteistcs d
(i)
uni mole alas eltminatin
aaction :
is
Cabo atfo
Fornaten d
slow
slow
eackon:
eveasi 6l step.
Slow
Rate
d CR]
Rate = k[R
(ni mo kaelh heactas
So, it s
ordey
frst
lows
fol
t
Kine cs.
RX:
o
Gii): Suactvity
R-cl
s
Genally
on be used.
weak base
acts
Rx >
R-I > > R-Br
and
(v)
3
H, 0:
wealc base
Casbo Gattn
Always
may
Solvent
itsuf
R-BH.
Jearange
Saytzeff
predeminates.
prtd ct pre
eg
H, ö:
cl
55
t=cth'
C2-btyl chloride)
Slo w
mech:
Step);
4-CI
c
(plana
Carbo ctton)
stepi):
fast
CHz
Note:
hefen
For
mre
st year
prepanatfon o
He
+ H,ot.
examples please
AKenes to pic
Atkenes by
(E1).
on
doohalsgenat
dehy
Note :
E1ce
unimolealas conjugade-boase
eliminattn
(e)
Reacionunimolecular Conjugate base
elimination).
E1cB
eaction .
tuwo steps
Tt is
Reaction :
ElcB
chavacteaistics
feratiey of
first
In +he
is fast
which
Cashaníon takes Plare
Ste
Stef
Carbnion
second step
Convered
will be
slow sep.
I n +he
(3
55-4
whih
GHsoH
alkene
Can be
CaHso Nat
into
streng base
(4
used
Kyl halide
alkyl
The
Casbaion
eg ( ) :
will
EccHcl,
mare Stahle
wich forms
nechaniSm.
wndergo
EtoH
=cclh:
fast
-H
mech: stepG):
-cch
stepi):
F
+
slow
f
FC=ccl.
CzHso a
ph-ciscy Br
egi):
’ ph-cH =cH +EtoH.. 55-8
(styrene
Mech :
fast
Step i):
ph-CH -cs
phCH-ch
Br
(Cenjugatebase)
(Aud)
CH
ph chcHy
Step (i),
we Knouw that,
slow
ph-cH=CH
heactk an, depends
Rate d
Aate = k
ph-cH-C-8rJ
slow s ,
(.. unimoleadas
Aate = k [C-8]
(: stp (i)).
Ke
[ c - Ke[AudCEto)
e
Substtute
CE+o]
Aad]
Ke
Rate= k K'
[eh-ciscy-or'[E+6]
Rate =
.:.
+ EtoH
Rate law
2nd ordev:
Subsituion
SN
(1
Vs
Singk step
is
prolects through
into
56
Climintion
heaction
Reactats
Con verts
"Penta - valln ted +ransittan
Stote
Convets into
Reactents
EL
heactta
step
Single
is
anti o-plana
prezlucts
+hrough
SN, E1
the
2
tnsitran State
Cases
aYe
mult-Sep
fematen o
Ln both
Seacthns.
Canbo at'
step)
dtomining
slou Step (rotte
is
|st stp
Crds
Reacvity
SN
He-x
E2
E1:
SN:
3*
SN1 .
Suactons
E
and
EE1
SN
SN,
of
Summary
all
Ovex
(3)
R- (a)
H-X
R-cHX
(?)
sis
isSN
Gives pola
eliminati
nucle
gives
2E
protic (or)
Solvent base
weak
is predomi
base used,
strong
a nates.
awhen
tempeÂat
uresR-6
fawouhed.
Rro
wth e9:
strng
Emaindy
)R-coo
in
mainly
Stng
base OK
JiKe
and
unbinded
wi
t
h
dhindee
with
nucl
St
e
r
ong
opki
l
e
s
strong
bases.
only
Gives heacion.
SN2
with
maunly
Gives
>
seak
SN
mainly
>Gives
baseseg:
and
bases-
CN,
I,
>
I
Solvoly
SNacton
No gives
(neny)
SN2
58
HC-B
Hc-CH-0-CH
J007.
+Na&r
SN
GHONat
Hc-cH-Br
GHsOH
(E)
(ss)
(o)
C1or)
unhindeed strong base
GHgoNat
egii): Hc-cH-CHa
(2)
(5s')
H,C-CH-cte
+
(E2)
(+92)
(SN)
(21)
CHs
Hc-BY
GHsoNat
CHg
GHsoH
:-cH-ci
C2sc)
(Su)
(9)
GHeoNat
eg (v):
GHsoH
(3)
(Ssc)
https://youtu.be/d26v88VYgX8
He =cH-cH
fmainly E
(a1%)
cHs
H,c = c-CH3
Etot .
E+E1)
(1007)
fuwons
atue
tempes
(. Hig h
e liminatton).
(To be Conhine d- )
mis ce|laneous
Other
with
Reactin
metal s
reats
AIKy| halidae
59
heacions
dy ether to give
with
Grignad Suagents.
R-Mgx.
chryethen
R-x
+ Mg
dy etheY
Hc-Br + Mg
Cmethyl
eg:
Ho-cH Br+ Mg
C
ompounds
Note:
coy ethes
Containing
(ethyt magnesim bromide
bonds
C-Metal
Conpounds.
Orpano metallic
bromide).
nesium
mag
Grignad
ahe
Called
Seagents a e
Ogano metalic Compounds
RMg,
In
highy
’
t
Car be- Mg hond
+he
is Cualent
but
polc.
eacts witt
H Containing
active
hydoCabons
ve
+
HC Mg Br
H*oH
+ H+oH
R-H
CHa
Conpounds to
+ Mg b) (OH)
+ M9(8d (o +)
Na ot
60
CAlcoho)
Cether)
R-o-R
(+hiol/+hio alohol)
R-SH
SH
R-`R C+hio eth)
R-S
CAIKyne)
R-c=
(ester)
Gpa
SN Patt
(R= cty, i.o0)
I
|X=c), 8, (or)
(AK azide)
R-N
Ng
’ R-NH
(i-ami ve)
R, NH
R-NH
CSamine)
2-amine)
RaN (3-amine)
Ci-amin)
R-NB
(Quaternay
awmornium
halid
(3-amiNe)
R-2 CAKane)
R-sCN (AlKy
+hio Cyanate
Nco
’-Nco
LiAIH4
(or)
2h) He o)
2n)AcoH (o
INaot
AIkyl
iso cyarate)
(AIKane
661
H,ö:
R
NaI
Acetne
Reaction with
KCN:
R-c=N.
CAIKyl Cy anide)
CR= CH, í,2)
Reacten
R
(er) (nitriley
with
AgcN:
+
AgCN
R-NC
CAKSI iso Cyanide)
(od (isonitrik)
Reaction with
KNO,:
R-N=ö:
(A1Kyl nitrite)
Reartien
with
Ag No:
Ag No
R-NO,
Coitro alKane)
62
Wurt
day ethe
2
R-R
2Na
R-X
+ 2 Na.
CAKane)
+
dyetheh
+
He-cy-&r
MechaniS m
2 Naßr.
Na
Co-butane)
AIKanes.
discussed in
Frankland methocd:
ethes
R-R
2R
CAlan)
Corey-bouse
Sythesis :
A|Kanes).
in
(Disussed
+2Lix.
Li
2R- + 4
2R-Li+
CuI
RCuLi + Rx
R CuLi
LíI
(Gilman Seagent)
R-R'.
CAIKane)
Líx
63
rdes .
Pre panation do AKyl hal
Erm
Alkanes
seacts
AIKanes
presence d
alky haide.
Ccl lor) &r)
halogen
with
Sunlght (o)
It
by heating
to
give
frea radrcal Substtuton
follews
mechanis m
Nott
ane
AIKanes
Refer
for
more
topíc fer
examples.
+
eg:
CHy
Cezces«)
nechanis m
Hc|.
ch
Hcl.
ccl4 t 4
+4 Cl,_
eg :
CHa
Ce ass)
He-CH-&r t tBr.
Hc-cI
B
cly
Cminor)
Cmajor)
Fren
AIKenes
additrcn
9eacts
wndes go electop hilic
H
with
AIky) halides.
9ve
to
Seacttn
Additicn o
ACen
64
A|KeneS
Hc|
to
HBY
o)
Rule.
"Markoni kov's
follouws
Addten
kov's
Ant markoni
HC-cH-cH t
unsy mmetncal
ony wh
takes plaa
ttc)
HC-cH-c}
eg: @):
He-cH=CH
+
tt8r
-CH-H
.&r.
Note:
Note:
Fr mere
exampes
A mechanis m
Refen A1Kenes.
+ Br/ccl4
vicinal dibromide)
Br
Prom
65
AIKYnes:
AIKynes heact wth
Here
dihalides.
t+el/HBr
2 moles d
to form
eminal
Cunbe used.
Hel/Hêr
HBY
Hc
-CEc
e9:
+
Hcl
+ Hcl
HcEcH
’
Hc=CH-cI
Hel
H-cHCz
BY
He -c=cH
He-CECH
Alynes
Note
to
uact
with
tetrabromo
ve
moles d
in ccl4
lkane.
ccl4
ccl4
eg:
HC=cH
Fox
Note:
HC=C-H
exampks
more exawnples
Refes
A|Kynes.
BY
Erom alkyl benzene 3
4
( prepcooien d
66
benzy |
-halides
h
(Dichlero
metthy bewzene)
(Renzy
CTolene)
ch
cla
cla
cgG).
çclg
CHcl2
CHcl
cH3
chlride)
(Trichlero
methy) benzere)
cl
CH-cHy
CHh-cH3
ct3
(or NB-s
(Benzy) bromide)
N-brUmo Succinímíde
Note?
NBS.
BY.
N&S
egiv):
Note:
ccl4
NBS.
allylic
(o
benzylic
brominating aqent
ro be Conkued-..)
67
From
alcohols
witt
(a) alcohol
alcohol
(c)
with
Pcls
with
Pcl3
alcohol
alcohol|
a)
Hx
with
SOcly
prepare
(best method to
R-ci)
Alcohol with
+
R
Reacivity
Nott:
3 R-oH,
where as
1R-ot
Suact
wnderg o
by s
HX
with
Hc|.
2'R-oH > 2R-o4 >
toward5 given H):
2 R-oH
HBY
HI >
given alcohol)
(touwands
Reactvity of Hx
of alcohols
Hyö:
SN2
Suactions.
fus
(
Puact
wih
mechanis
Hcl:
HcI
but
Hcl
is
used with
3-alchols
in
Hhe
ncls
seadily
and
Zncl,
2-alcohols
Con antroded
68
+
R-cl ++ H,0 Grove's
H+c|
proass)
2-alcohol :
SN
(Fr i- alcohol)
mech :
SN
R-cl
R-OH
ROH +Zcl,+ Hcl
t+
H,o + 2ncl,
CFx 2-dcohels)
SN!
mech:
R-öj+ +nch
+ [Ho-zncla
R
R-ozncl,
Canbo
Caticn)
R-cl:
CL +
+
R-oH
25c
Conc' Hc|
R-cl
(3-alcohol)
c-CHy-cl
Zncl
He-cH,-oH
eg i):
He-cH-OH
+
Hcl
Hcl
Znch
cH3
Hc- #-e|
A
(2)
cltzoH
(a)
25c
(Cone)
-c)
+ H,0
69
HBr:
The
preene d
-al cdhols, but not ter
for
Con^ H, so
2 &
in
Catsied out
is
eactien
3- a cohols
R-oH
+
HBr
R-Br + t 0
C¡r-Hys
(()
R-Br.
HBY
R-oH
R-X
Nax
Note:
Ci, a)
+ NaHS oy
(K= cl,&)
HI:
R-I
HL
H Pa
KI
Note :
A
Jeacts witth
Note :
at
Cne
Conc
Hci, HBY
tem paate (2s'c).
Conc
HL
HBY
Hc|
R-oH
Hel
R-cl
HRY
R-ot
R-Br
HT - I
)
6)
Hcl R-cl
2ncl
(2)
A
Cunc.HeY
Conc. Hc|
R-H
(3)
Noe:
R-OH +Nac
R-oH
R-cl
25c
Nott:
Note:
R-oH +Naß
R-I
C3)
(3)
25c
Hyso
Conc-HI
25c
R-cl
R-I
R-ot
(2)
A
R-Br
45%. HgPy
R-oH +KI
Ci, a)
Cphosphorous penta chloride)
(6)
Alcohol wth
Poclg
R-cl
Cphosphory|
R-OH
chloride)
eactg
Note :
SN
eg i):
with
pcls
mechaniS m.
ot
t Pocl t+ Hcl
+ Pcls
e
Note
by
Prs,
highy
+ Poclz
unstae.
+ Hc|.
(c)
Pcl3 :
Al cohol with
3 R-OH
(phosphovous trichloride)
+ Pclz
3 R-cl
+ H; Poz
3 R-oH
is
So, we take
unstable.
PtI,_
H POg
R-I +
P+I
R-OH +
mistuse d
+ Pclg
3
3 OH
+ H3 Poz
Note
I, 2-alchols
adcohol
(Alheady
witt
heact
Socle:
with
Pcl3 by
SN
SN
mechanism.
( thiongl chloride)
discussed
Socly
R-cl
(Retenthon)
R-cl
(InveYsien)
Gases
(parzen's procede.
It
methoed to
products ae gases.
R-cI, sina the by
e.
RcooAg
esters
furms
Note:
HccooAg
Hc-cH-8r
co,
+
ccle
&r. Ag +
+
&. Ag+co,
HC-Br
Hc-cootg
ccl4
R
B + BY
R-fo-As
R-go8r
BrAg
Bs
+
yield
R-ci.
is:
I>2>3
+
cal) radi Chree
poor
gires
mech:
cle
a
dyield
haide
The
R-G-oA9
composeed
by
cla
Cor)
to
for
m
alkyl
asesolutton
de
Salts
d Silve
Caboylte
in aeids
cl
diecker
Suaction
2
BorodineHuns
3
2 R-5-og +
este
( 2*1 ratio)
This
eact o.
Simonini
Bin baun -
Called
heactn is
2Ag I
Finkelstein Reaction:
AIKy íodides ase
with
Rcl/e-r
treating
prepared by
corve nien+y
nore
Nat
in Aetone
metthasoj.
Na I
Acetone
4
R-L
Nax
Cx= c,ex)
2.
Tt follows
So,
SN
mechanism
|>2
Juactvity
+
Acetne
eg G):
Naßr
c-Br
Acetene
-I
Nac)
cl
+- N a
Acetene
Naßr.
Swarts eaction:
(8)
Can be
AlKyl fluorides
Covrespanding
Re/e-ar/a-z
Such as
fluorides
prepaseed
+
by the
Seact cn of
inorgaoic -
with
AgF, H9,F,
SbE,, AsF, ete;
HC-F t Ag &r.
Ag F
+
Agc|:
e9:
R-F
Note:
Cos
also be
by the
obtai ned
H-CN Solvest
18- Crow-6.
in presene
CHy-CN
eg:
He-ct-cl
J8-Crown-6
ehes
Not:
He-ctt F + Kc|
12-Cowh-6
: 0:
i0:
whih binds
physical pro pertes
()
+5
al Kyl halides
of
physiCal stat:
H -cl,
He-8r,
Hc-I
andd
he
3ases.
majority of the
big her
members
liquids.
Suweet - smelling
are
are
CaH-cl
Boiling points:
2
valueS Of the
order of
The
akyl halides
In
is :
roup of
a
points
boiling
0f
h
> R-F
R-cl
>
R-er
R-L >
isomertc
lkyl hardes,
the ordes of
boiling ponts
the
He-cis-Cl-c-c,
Hc-tCH CHy
Ch-butyl chloricla)
C2-buty! chlerice)
B-P:
Density:
R-I
Ameng poly halides
R-Br >
R-cl
R-F.
ccly >> CHcla > CHcl, > Hp-c
3-buty)
chloride)
halides:
olvents.
Soluble
R-c)
The-end
seagent
Lucas
ahydhous
Zncl
Conc!
+Hcl
Note:
Hc|
zncl,
ment
Anong
methyl
oTganic
let
Cova
S
Dipole
m
water
^olusle
Compound
s,
in
halides
in
AIKy|
are
lity: Solubi
6
Note D:
SN'
Solvent effect on
but
appreciaby
Com pounds
dissoIve,
They
qute
and
alcohols ,
do not dissol ve
most
waterY.
for pro moting
Solvent
effecte
most
water ( Ho)
joniSaten
reactions:
usually
miled So lvents
oftn
used.
+ Hyo,
CH,oH
e : G)
are
Solvents f r
míxed
are
however,
Comn
eactions.
Note2
protic
pola
1n
Ho,
Solvent like
more
lace
solvatiCh taKes p
nuclhophli aty
de creases
So,
în Small
decveasiug
halide ions
ovde is:
nuckophiliaty
anim
Sol vatan c
In apoHc Solut,
nuckop wlicity
place.
Now,
density (od basiaty.
The
Chuge
more
So,
basicty chage density
is
nuchoi
Acleoçl libity dcveasi ug crd:
doesnot
de uided y
wich
takes
has
nM ckophi lic
(: F is storg base)
Ccl
H,o
+
+
Soln,
CHE
H-oH
5Cct
Rco0 4
Nuceophliaty
a) pola
pola
R-o
prokc CHso
DMSO)
aprotc soluents.
isin
lone pair
Sojh
HOc|.
Cory ugatien
R
R-:
C ho Congugahian).
RcOO
nuceoplic than
nuceopilic than Rcoo
more
R-o is
nore
R-o is R-6is strnger base
a
Dmso
han
The -end
Rcoo