CHE}I24 Dr. Spence

1 . Calculate the degree of unsaturation for each of the following compounds:

Coo

6lCoHrrNOz

7

CeHllN2OaBr

[,-)

CaH+OClz

Ll

C2aH2aN3OP

F

1,1l . /

CroHs

1How many degrees of unsaturation are present in each compound below?

T',('l-'

o N ^ t t z-o-$-o- ^ |6 K )

OH

n1

q5lo \

V.A.--\ Itf N-l) ).,.2

3ooo b

Name each of the following compounds according to IUPAC rules.

(E) - 3--etli1 I - j-n on enrr, |

(o*:)S - n"etu tl't - decer.-(,

( z ) - 2,6-,rN,,nuth7/ - rl - yryl- 1-hefkr{-"

.",.L<., r(y H,c=cHr*r,r, O(

, "'I "' 'y tt"t h

\l,l'J,chlo,rp^ l-hu1erL I Ct)-2,r"'{imett^71-}-hereru lr l5 -tth i - | .rnrlhl I ctsl,ihV ece_ I ,Z ,3- C*,n*.1h7l -

I ,t * clc/*kxqC,tv'L

,/,'JZ-4)..,,.[Jr l

f -- lII,#

(e)-;- (Wl-Z-oc.hs*L

CHEM 24

t lt - l

.q.

(a) oL

.t-V

3

I

(b) -,,\.,-

I

1

II,k

I/b'/r u > ? o) f v

/,,\u ( )ccrrnrlt Il9u,,rcfl1'L \.r'

:,,!rrf'"1"r f,"",n

narc- fuV: nrlqtt+avk-

I

rrn;f€ !..r9 'gy1;6( f+"VV

?'",\.,6-ocn.

1,_

{ra,rnu\ lh"4f\xzt \.It rz rrlrt+1..1 Tt-q- ; ,"RM.b\ 9!"iU_ gttVtr- tYun

t{u'n"tRank following carbocations from most stable (1) to least stable (6).

@

r-r-\/

Lal

If the following carbocations can rearrange to a more stable carbocation, draw the structure of

the more stable carbocation and state why it is more stable. If it cannot, state why.

,"\r"\ -"\.'\

@ o

/\@

U .Y\-/

361

er,/t\rt;

\1{II

IIIII

I

,

NIJ--J

e?tl?q{?"(-

n;,,') 1g2c47u'rtt{

21'.Y,!,ztQ

Dr. Spence

For each group of alkenes shown below rank them in increasing order of stability (most stable :1). For each series, what is the main principle determining this stability?

( )\:,/

I

o'n5 g{re,in

';u!::tr1"tr,r\n t f+rnt gtgin

L

I

\

7-? *ru,.th f17tO4If the following alkenes can isomerrze to a more stable alkene, draw the strucure of the morestable alkene and state whv it is more stable. If it cannot isomerize to a new alkene. state why.

ry # )4- o'?II

II

\/

C'*;rrn"t 6r'lrwt?t- i€nCqn,n.*t fifr I

I..\2'\

4 7l 1 -

Ii

.t/)/\./

crlrtcrtn00?t

:tevLL(Ct2""rr,Vlce)

*J"'/L"j " >r"

CHEM24 Dr. Spence

8. In the electrophilic addition of HBr to the following alkenes one is found to add the hydrogen tothe end carbon while one adds hydrogen to the middle carbon. Which adds to the middle andwhich adds to the end? Draw the products of these reactions and explain your product in termsof the two versions of Markovnikov's rule.

fla;,.nfarL 5-labr l,dYcF3cH:cH, & {4+ cF3ocH:cH2

rrlo{L t"lt-bl-L

\./o!rr-Crl -CHrg

o C

= *nr+lAwv,z DnilXt Jb e,a..[

aTl-er*

HCI./-\-,,'\rr-

----------------

HBr..--------------

CF," -O-Ci-/, -- / v

( t -

b

\ /"rto.-

-Cao.rr,t IY*rrt at rno{tt-

?lh'\)Lp- atlLq"r{.-"

acHz

befier{I u

9.

I

lv"/II^"N

c-l

\"r^-/ts.

nt{-- 5aL> H3po4(-,

...............

\,:..

Ir,YL/

aY HrPo4 fil/(' -

L-jJ

Wp6uaLL

{

* cdr\ Z @-o- cYlCF*

a

Reactions. Give the structure of the malor organic product(s) expected from each of thefo l lowingreact iong. I - /TbX_a4._> q j1v ' o x t /

CHEM 24 Dr. Spence

Mechanisms. Provide a complete stepby-step mechanism for each of the reactions on the lefthand column in question 6 and for the reaction below.

10.

'.1(tr :.r\

./-\Z

(t

HBr#

\X.L-)--r

t HBr (1 equiv) IIBr (2 equiv) '-f

12. For the diene in question 11, which alkene is more stable? Which alkene is more reactive?Draw two reaction energy diagrams (side by side, one for each alkene) illustrating relativeenergy differences of alkenes, activation energy, transition state energy, and intermediate energyfor the addition of HBr. How do these diagrams help explain your answers regarding alkenestability versus reactivity and that more stable alkenes are not necessarily less reactive?

r.,lorR "t,bk- /..ffi-rncct cev.trtrt- (1"^e!)

frlk""t A ftty*"< beWr thu:1hf ^\b"i| crlTp hc^1

r:r lo^gf

AL"* Snreft 6xml /l'7erttf-')'(s T 9,4

Rank the following alkenes from most reactive (1) to least reactive (6) towards electrophiles.

r")L

/\zII

\

t t l\-\

q-1{

a"--"Y

I

13.

o:y11. When molecules with two alkenes react the product will depend on how many equivalents of HX

are added. If two molar equivalents are added, then both alkenes will react. If only oneequivalent is added only the more reactive alkene reacts. Predict the products from the followingreaction with one and two equivalents of HBr.

14. Calculate the degree of unsaturation, and draw three constitutional isomers for the molecular formula C6H10. 2° of unsaturation; possibilities include:

15. Calculate the degree of unsaturation, and draw three constitutional isomers for the molecular formula C6H8. 3° of unsaturation; possibilities include:

16. Calculate the degrees of unsaturation and draw two reasonable structures for each of the following molecular formulas. a. C6H6 4° of unsaturation:

b. C3H4

2° of unsaturation

17. For the following pairs, determine which compound is more stable, and briefly explain why.

18. Using the stability arguments we have learned, label which product would be major in the following reactions. Briefly explain why. a.

b.

cis trans-more stable

more highly substituteddouble bond

2 R groups 4 R groups

resonance stabilized

no resonance stabilization

biggest groups trans

O O

resonance stabilized

no resonance stabilization

resonance stabilized

pi bonds are not in resonance so no resonance stabilization

CH3CH3Br

NaOH

majormore substituted

double bond

CH3 CH3 CH3I

I

+HI

majormore substituted

cation intermediate

19. Using the stability arguments we have recently learned, indicate whether the product or the reactant would be favored. Briefly explain why. a.

product: biggest groups are trans b.

reactant: more substituted carbocation is more stable 20. Predict the major product(s) for the following reactions. a.

b.

both cation intermediates are 2°, so we get both possible products c.

21. Determine the products of the following reactions. a.

H

HBr Br

HBr

Br

Br

+

excess HBr Br

Br

HBr

Br

b.

c.

22. Name the following compounds using IUPAC nomenclature. Don't forget to include stereochemical designations where appropriate. (e.g. E, Z, cis, trans) a.

(Z)-4-ethyl-3-heptene b.

(Z)-4-isopropyl-1-methyl-1-cyclooctene c.

(Z)-3-methyl-1,3-hexadiene 23. Draw the skeletal structures corresponding to the following names. Make sure to clearly indicate stereochemistry. a. (Z)-4-methyl-1,4-octadiene

HBr

Br

HBrBr

24. Consider the following reaction.

a. Draw a reasonable mechanism that accounts for the observed product. Show all steps and intermediates.

b. Draw a reaction coordinate diagram for the reaction. Label the transition state(s), intermediate(s), the energy of activation(s), and the energy of reaction.

HCl

H Cl

+HH H HH H

=

Cl

+Cl

Cl

G

Progress of Reaction

H

H H

Cl

TS1 TS2

TS3

Grxn

G1

G2

G3

c. Draw the structure(s) of the transition state(s) using the standard conventions.

HH

+

++

H+

+

Cl-

transition state #1 transition state #2 transition state #3