Organic Chemistry Functional Groups 221160

8/17/2019 Organic Chemistry Functional Groups 221160

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Organic Chemistry I

From atoms to molecules and beyond Functional rou!s

"onding and #olecular $tructure

%esonance and &somers

&ntermolecular interactions

'ydrocarbons

$ubstitution and Elimination %eactions()ygen Containing Com!ounds

*mines

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Lewis Dot Structures

%ules +or ,riting Find total - valence e.

1 e. !air / 1 bond0 *rrange remaining e. !er octet rules E)ce!t eriod 3 can have e)!anded octet vacant d orbital

reuired +or hybridi5ation6

Formal Charge - valence e. isolated atom6 - valence e. le,is structure6

$um o+ +ormal charge +or each atom is the total charge onthe molecule

*C* charge distribution de!ends on electronegativity

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Functional Groups

List #1- Critical for the MC!

*l=ane CC *l=ene C/C *l=yne CC

*lcohol %(' Ether %(% *mine %


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A

Functional Groups

List #"- lso seful

*l=yl $alogen emdihalide Bic dihalide

'ydro)yl *l=o)y 'emiacetal 'emi=etal #esyl grou! osyl grou!

Car%onyl *cetal *cyl

*nhydride *ryl &en'yl (henyl 'ydra5ine 'ydra5one Binyl Binylic *llyl


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&on)s

y!es &onic

Covalent Coordinate covalent

olar covalent

'ydrogen "onds

com!lete trans+er o+ electrons

shared electrons

(ne atom !rovides both electrons in ashared !air.

uneual sharing o+ electrons

bonds bet,een !olar molecules

containing ' and O* +* or F

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Co,alent &on)s

$igma σ "et,een s orbitals

$mall strong lots o+ rotation

i Π "et,een ! orbitals

:iscreet structure ,ea=er than sigma no rotation

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Co,alent &on)s

1D1D


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&on)s

&n the !i bond o+ an al=ene the electron !air have

*. 33 ! character and are at a lo,er energy level

than the electron !air in the σ bond.

". 33 ! character and are at a higher energy levelthan the electron !air in the σ bond.

C. 1DD ! character and are at a lo,er energy level


:. 1DD ! character and are at a higher energy level


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$y%ri)i'ation

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$y%ri)i'ation

%emember *ll !i bonds are bet,een orbitals

e+toverG and $ orbitals hybridi5e

!artici!ate in sigma bonds

E) '2C/C'2

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$y%ri) &on)s

$u++i) C bonds 'ybridi5ation

ercent

$

"ond *ngle

"ondength

"ond$trength

ane

ene

yne

yl

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1?

$y%ri) &on)s

$u++i) C bonds 'ybridi5ation

ercent

$

"ond *ngleo

"ondength

!m6

"ond$trength

=HImol6

ane CC s!3 2?7? 1D9.? 1?4 34A

ene C/C s!2 33AA 12D 134 A12

yne C/C s! ?D?D 18D 12D 83?

yl $idechain


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1A

Special Cases O an) +

>no, ty!ical bonding +or C


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*6 s!2 s!2

"6 s!2 s!3

C6 s!3 s!3

:6 s!3 s!2

For the molecule 1*. penta)iene* what

type of hy%ri)i'ation is present incar%ons # 1 an) # / respecti,ely0

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S2(34 molecular geometry

valance shell electron !air re!ulsion

E(#E%J / #inimi5e electron re!ulsion

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molecule Lewis structure Shape molecule Lewis structure Shape

&eCl" Linear* sp

SF. $eesa, SO/

!rigonalplanar* sp"

ICl/ sha!ed +O"

- &ent

C$. !etrahe)ral* sp

/ +$/

!rigonal

(yrami)al

(Cl5

!rigonal%ipyrami)al*

)sp/SF

6

Octahe)ral*)"sp/

IF5 $uare yramidal ICl.

- $uarelanar

S2(31. :ra, the e,is dot structure

2. lace electron !airs as +ar a!art as !ossible

then large atoms then small atoms

3.


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+O7 L2!8S MO2 S!FF 3O+D9

KeLve seen static !ro!erties o+ atoms and moleculesM

2D


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Delocali'e) e- an) 3esonance%esonance +orms di++er only in location o+ e.

o be a signi+icant resonance +orm must be sta%le

%emember octet rule and consider +ormal charge

%eal structure / blend o+ !ossible resonance

structures resonance hybridG

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3esonance4 ci)s an) &ases

Con;ugate stabili5ed by %E$(


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Stereochemistry

&somers same molecular +ormula di++erent

s!atial arrangements

:i++erent s!atial arrangements

di++erent !hysical and chemical !ro!ertiesO

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Stereochemistry4 Isomers

C(


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%(*&(<

Conformational isomers :i++erent s!atial

arrangement o+ same molecule but doesnLt reuirebond brea=ing to interconvertO rotationalG isomers Chair vs. boat $taggered vs Ecli!sed auche vs *nti

:(E$ reuire bond brea=ing to interconvert

configurational isomers2?


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:("E "(


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Khat =ind o+ isomers are the t,o com!ounds belo,P

= :iastereomers

&= Enantiomers

C= Constitutional isomersD= eometric &somers

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http://en.wikipedia.org/wiki/Image:L-tartaric_acid.pnghttp://en.wikipedia.org/wiki/Image:D-tartaric_acid.pnghttp://en.wikipedia.org/wiki/Image:D-tartaric_acid.pnghttp://en.wikipedia.org/wiki/Image:L-tartaric_acid.png


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Enantiomers di++er in rotation o+ !lane!olari5ed light E)cess o+ one enantiomer causes rotation %ight cloc=,ise de)trarotary d6 or N e+t countercloc=,ise levarotary l6 or Q

$!eci+ic rotation RaS / a I lTd6

%acemic ?D?D mi)t o+ enantiomers


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Stereochemistry4 Chirality

% and $

1. *ssign !riority by atomic number &+ attachments are the same loo= at the β atoms

2. (rient lo,est !riority -46 a,ay +rom the observer

3. :ra, a circular arro, +rom 1 to 2 to 3 % / cloc=,ise $ / countercloc=,ise

E and U :i++erent than cis and trans U/ same side o+ high !riority grou!s E/o!!osite side o+ high !riority grou!s

3D3D


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7$! &O! &2!722+ MOL2CL2S0


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Intermolecular interactions

:ue to :&(E #(#E


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Intermolecular interactions

ondon :is!ersion Forces "et,een 2 instantaneous di!oles

:i!oledi!ole interactions :i!oledi!ole or di!oleinduced di!ole

'ydrogen "onds

$trongest di!oledi!ole interaction

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7hen al%uterol is )issol,e) in water* which of the


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7hen al%uterol is )issol,e) in water* which of the

following hy)rogen-%on)e) structures )oes +O!

contri%ute to its water solu%ility0

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$>D3OC3&O+S

he +irst and sim!lest class o+ molecules ,e

need to get +riendly ,ith +or est :ay

3?


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3A

I(C +aming Con,entions

I(C 3ules for l?ane +omenclature

1= Find N name the longest continuous carbon chain.

"= &denti+y and name grou!s attached to this chain.

/=


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l?anes

hysical ro!erties $traight chains # and " increase ,ith length "ranched chains

" decreases less sur+ace area v:K +orces6

# Q a little more com!licated due to crystal structure Khen com!ared to the straight chain analog the straight

chain ,ill have a higher # than the branched molecule." amongst branched molecules the greater thebranching the higher the #.

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l?anes Important 3eactions


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4D

l?anes-Important 3eactions(retty Darn nreacti,e

Com%ustion *l=ane N ()ygen N 'igh energy in!ut +ire6 roducts '2( C(2 'eat

$alogenation &nitiation ,ith B light

'omolytic cleavage o+ diatomic halogen

Jields a +ree radical

ro!agation chain reaction mechanisms6 'alogen radical removes ' +rom al=yl Jields an al=yl radical ,hich can ma=e more radicals

ermination %adical bonds to another radical

%eactivity o+ halogens F V Cl V "r VVV &

$electivity o+ halogens 'o, selective is the halogen in choosing a !osition on an al=ane6 & V "r V Cl V F

more electronegative means less selective

$tability o+ +ree radicals more substituted / more stable so halogenation @ most su%8) C

arylVVVal=eneV 3o

V 2o

V 1o

Vmethyl

4D


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Cycloal?anes

eneral +ormula C'26n or Cn'2n


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Cycloal?anes

Cyclohe)ane E)ist as chairG and boatG con+ormations Chair con+ormation !re+erred because it is at the lo,est

energy. K'JP6

$ubstituents can occu!y a)ial and euatorial !ositions. *)ia A6 !er!endicular to the ringEuatorial A6 roughly in the !lane o+ the ring "ig substituents !re+er to be euatorial Q less cro,dingGO

Khen the ring reverses its con+ormation substituentsreverse their relative !osition

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Cyclohe


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32C!IO+S99

hings start getting more e)citing once ,e start substituting ' +or

more interesting +unctional grou!sM so letLs get ready +or some

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4?

Su%stitutions

$ubstitution

one +unctional grou! re!laces another

Electro!hile ,ants electrons has !artial N charge


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2liminations

Elimination

+unctional grou! lost double bond made

(+ten a e,is base is res!onsible +or ta=ing 'leaving behind an e)tra !air o+ e. +or the /

he o!!osite o+ elimination is a))ition

4A


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Su%stitution an) 2limination

E1 elimination unimolecular #echanism t,oste!

1. s!ontaneous +ormation o+ carbocation $(K6 2. "ase abstracts beta '

>inetics rate de!ends only on the substrate %/=RreactantS Favored ,ith good stable carbocation ,ea= base

rotic solvents stabili5e carbocation Can see carbocation rearrangement

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7hich of the following


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g

car%ocations is the most sta%le0

=C'3C'2C'2C'2

&=C'3C'2C'2C'C'3

C

= C'363C

D=C'3 49


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?D


$


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?1


E2 elimination bimolecular #echanism C(inetics rate de!ends on substrateNbase %/=RsubstrateSR"S Favored ,ith strong bul=y base

&+ you see 'E* thin= Elimination E2 reactions o+ten run in solvent o+ con;ugate acid K'JP6

?1


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?2

&en'ene

* s!ecial molecule a s!ecial case o+ substitutionO *ctually itLs addition and then elimination.

*romatic molecule $tabili5ed by resonance ndergoes net su%stitution not addition K'JP6

$ubstituents determine subseuent reactivity Electron donating grou!s activate the ring and are ortho!ara directors Electron ,ithdra,ing grou!s deactivate the ring and are meta directors $alogens are electron ,ithdra,ing " are ortho!ara directors

?2


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?3

&en'ene4 Su%stituent 2ffects

?3


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&n ,hat order ,ere the substituents addedP

'o, can you tellP

?4


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OA>G2+-CO+!I+I+G COM(O+DS

*nother class o+ molecules ,e need to be +amiliar ,ith

??

O C t i i C )


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?A

Oetones

Carbo)ylic *cids

*cid :erivatives *cid Chlorides

*nhydrides

*mides >eto *cids and Esters

?A

l h l


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lcohols

(ne o+ the most common reactions o+ alcohols isnucleo!hilic substitution. Khich o+ the +ollo,ingare %E in regards to $


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lcohols

hysical ro!erties olar 'igh # and " K'JP6 #ore substituted / less acidic

C'363C(' !>a / 18.DD C'3C'2(' !>a / 1A.DD C'3(' !>a / 1?.?4

Electron ,ithdra,ing substituents stabili5e al=o)ide ion and lo,er !>a. ertbutyl alcohol !>a / 18.DD a / ?.4

eneral !rinci!les ' bonding *cidity ,ea= relative to other ( containing com!ounds

?8

lcohols


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+aming

$elect longest C chain containing the hydro)yl

grou! and derive the !arent name by

replacing –e en)ing of the correspon)ing

al?ane with –ol =


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lcohols-O


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A1

Common o)idi5ing and reducing agents

enerally +or the #C* ()idi5ing agents have lots o+ o)ygens

%educing agents have lots o+ hydrogens

O#n(4


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A2

synthesis

*ldehydes =etones esters and acetates can bereduced to alcohols , strong reducing agents suchas


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A3

,ia a strong aci) catalyst

%(' N 'Cl %Cl N '2D

(' is converted to a much better leaving grou!,hen !rotonated by a strong acid

For tertiary alcohols 'Cl or '"r rimaryIsecondary alcohols are harder need $(Cl2 or

"r 3

A3


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A4

&n the reaction above i+ the reagents in the+irst ste! ,ere re!laced ,ith i*l'4 ,hat

!roduct ,ould resultP

a6 c6

b6 d6

A4

('

('

('

(

('

('

(''(

Car%onylsC % ) %l % ) ) t O


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A?

Car%on )ou%le %on)e) to Oetones nucleo!hilic addition6Carbo)ylic *cids nucleo!hilic substitution6

*mides

A?

l)ehy)es an) etones


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AA

l)ehy)es an) etones

hysical !ro!erties Carbonyl grou! is !olar 'igher " and # than al=anes K'JP6 #ore ,ater soluble than al=anes K'JP6

rigonal !lanar geometry reduction yields racemic mi)tures

eneral !rinci!les E++ects o+ substituents on reactivity o+ C/( e ,ithdra,ing increase

the carbocation nature and ma=e the C/( more reactive

$teric hindrance =etones are less reactive than aldehydes *cidity o+ al!ha hydrogen carbanions α β unsaturated carbonyls resonance structures

AA

l)ehy)es an) etones+aming lalala it8s the same rules9


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+aming lalala it s the same rules9

+aming l)ehy)es %e!lace terminal –e o+ corres!onding al=ane ,ith –al =

arent chain must contain the QC'( grou!

he QC'( carbon is C1

Khen QC'( is attached to a ring ,e say carbaldehydeG

+aming etones %e!lace terminal –e o+ corres!onding al=ane ,ith –one.

arent chain is longest chain containing =etone


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l)ehy)es an) etones


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A9

l)ehy)es an) etones

>etoenol automerism >eto tautomer is !re+erred alcohols are more

acidic than aldehydes and =etones6.

A9

Guanine* the %ase portion of guanosine* e


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7D

7hich of the following structures represents the

enol form of guanine0

7D

l)ehy)es an) etones-

reactions at a)acent positions


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reactions at a)acent positions

*ldol aldehyde + alcohol 6 condensation (ccurs at the al!ha carbon

i electrons in enol act as nucleo!hile

"ase cataly5ed condensation removal o+ '2(6

Can use mi)tures o+ di++erent aldehydes and =etones

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l)ehy)es an) etones


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l)ehy)es an) etones

(rganometallic reagents


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Car%o


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Car%o


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7A

+aming

Carbo)ylic acids derived +rom o!en chainal=anes are systematically named by

re!lacing the terminal –e o+ the

corres!onding al=ane name ,ith –oic acid . Com!ounds that have a QC(2' grou!

bonded to a ring are named using the su++i)

Qcarbo)ylic acid. he QC(2' grou! is attached to C -1 and is not

itsel+ numbered in the system.

7A

Car%o


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Carbo)yl grou! reactions etones undergo a))ition K'JP6

#ust contain a good leaving grou! or a substituent

that can be converted to a good leaving grou!.

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Car%o


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%eduction Form a !rimary alcohol

i*l'4 is the reducing agent

C'3C'26AC((' C'3C'26AC'2('i*l'4

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Car%o


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Carbo)yl grou! reactions :ecarbo)ylation =no, that it ha!!ens C(26

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Car%o


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8D

Fischer Esteri+ication %eaction *lcohol N Carbo)ylic *cid Ester N Kater *cid Cataly5ed !rotonates Q(' to '2( e)cellent

leaving grou!6 *lcohol !er+orms nucleo!hilic attac= on carbonyl

carbon

hese bonds are

bro=en

'N

8D

Car%o


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p

$ubstitution reactions =eto reactions sho,n

consider enol reactions

To make->

SOCl2

or PCl3

Heat, -H2O

R'OH, heat,

H+-

R 2NH

heatHO-

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Car%o


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'alogenation enol tautomer undergoeshalogenation

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ci) Deri,ati,es+aming


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*cid 'alides %C(Y6 oyl halideG instead o+ oic acidG e) ethanoyl chlori)e

*cid *nhydrides %C(2C(%L6 Hust re!lace the ,ord acid ,ith anhydride.

2 acetic acid acetic anhy)ri)e nsymmetrical anhydrides are named by citing the t,o acids al!habetically.

*cetic acid N ben5oic acid acetic %en'oic anhy)ri)e Esters %C(2%L6


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8?

ci) Deri,ati,es- 3eactions ofDeri,ati,es


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8A

Z'ydrolysis N,ater carbo)ylic acidZ *lcoholysis Nalcohol ester Z *minolysis Nammonia or amine amideZ%eduction N ' aldehyde or alcoholZrignard N (rganometallic =etone or alcohol

8A


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Organic Chemistry Functional Groups 221160