Cross Ozonides from Pairs of Symmetrical Olefins - Advances in

62 Cross Ozonides from Pairs of Symmetrical Olefins ROBERT W.

MURRAY

and

GREGORY

J.

WILLIAMS

Downloaded by FUDAN UNIV on March 6, 2017 | http://pubs.acs.org Publication Date: January 1, 1968 | doi: 10.1021/ba-1968-0077.ch062

Bell Telephone Laboratories, Inc., M u r r a y Hill, N. J.

3-Heptene ozonide has been produced by ozonizing mixtures of 3-hexene and 4-octene. The 3-heptene ozonide cis-trans ratio has been determined for a number of sources of this ozonide and found to depend on the stereochemistry of the olefin or pairs of olefins used to generate it. The effect of varying concentrations of added butyraldehyde on the ozonolysis of 3-hexene has been determined. The yields and cis-trans ratios of 3-hexene and 3-heptene ozonides depend on the butyraldehyde concentration. ' T h e C r i e g e e (2) m e c h a n i s m of ozonolysis a l l o w s f o r t h e p o s s i b i l i t y of i

A

t w o z w i t t e r i o n s a n d t w o c a r b o n y l moieties

u p o n ozonolysis o f a n

u n s y m m e t r i c a l olefin. T h i s p o s s i b i l i t y leads to t h e p r e d i c t i o n that s u c h ozonolyses c o u l d l e a d to the p r o d u c t i o n of three o z o n i d e cis-trans p a i r s . ^°s^ RCH=CHR'

+

O

a

j^RCH

CHR'J—

RHC

OO +

+

R'CHO

R ' H C > — O O " 4- R C H O * +

O—O

RHC

/

\

O—O

CHR +

/

RHC

x

o

O—O

\

.CHR' +

y

R'HC

^cr

\

CHR'

F a i l u r e to find t h e t w o s y m m e t r i c a l or cross ozonides f o r 3-heptene l e d C r i e g e e to postulate a solvent cage ( 2 ) w h i c h p r e v e n t e d t h e cleavage fragments

f r o m p a r t i c i p a t i n g i n exchange o r cross reactions.

c e n t l y a n u m b e r of reports ( 5 , 8, 9,10, 11,12,13,14)

M o r e re

h a v e i n d i c a t e d that

cross ozonides c a n b e p r o d u c e d f o r several u n s y m m e t r i c a l olefins. T h e fact that t h e percentage cross o z o n i d e p r o d u c e d decreases w i t h olefin c o n centration

(8)

p o s s i b l y indicates that the earlier failures to find cross

ozonides m a y s i m p l y h a v e b e e n c a u s e d b y the olefin c o n c e n t r a t i o n u s e d . 32 Mayo; Oxidation of Organic Compounds Advances in Chemistry; American Chemical Society: Washington, DC, 1968.

62.

MURRAY

Cross

AND WILLIAMS

33

Ozonides

T h e observations of s y m m e t r i c a l cross ozonides f r o m u n s y m m e t r i c a l olefins suggest that u n s y m m e t r i c a l cross ozonides o u g h t to b e p r o d u c e d f r o m pairs of s y m m e t r i c a l olefins. C r i e g e e h a d e x a m i n e d this p o i n t earlier (2)

a n d f o u n d that n o detectable amounts of 3-heptene o z o n i d e w e r e

p r o d u c e d w h e n a m i x t u r e of 3-hexene a n d 4-octene w a s o z o n i z e d . A g a i n , this m a y h a v e b e e n a result of the p a r t i c u l a r olefin concentrations

used.

T h e recent observations that o z o n i d e cis-trans ratios i n b o t h cross ozonides (5, 10, 11)

a n d n o r m a l ozonides (4-14)

c a n d e p e n d o n olefin stereo

c h e m i s t r y as w e l l as steric factors i n the olefin (11) investigate

p r o m p t e d us t o re

t h e p o s s i b i l i t y of o b t a i n i n g u n s y m m e t r i c a l ozonides

from

pairs of s y m m e t r i c a l olefins. S u c h a n i n v e s t i g a t i o n presents a n o p p o r t u n i t y


to examine o z o n i d e cis-trans ratios a n d y i e l d s w h e r e several n e w r e a c t i o n variables are possible.

Experimental M a t e r i a l s . T h e olefins w e r e o b t a i n e d f r o m the C h e m i c a l Samples C o . a n d w e r e f r o m f r e s h l y - o p e n e d bottles. T h e a l d e h y d e s w e r e d i s t i l l e d i m m e d i a t e l y b e f o r e use. O z o n o l y s e s . T h e g e n e r a l p r o c e d u r e d e s c r i b e d earlier (11) w a s u s e d . A l l ozonolyses w e r e c a r r i e d o u t at — 7 0 ° C . a n d w e r e c o n t i n u e d to 7 5 % of t h e t h e o r e t i c a l a m o u n t of ozone r e q u i r e d . T h e G L P C analyses w e r e c a r r i e d o u t o n a n A e r o g r a p h m o d e l A - 7 0 0 gas c h r o m a t o g r a p h , u s i n g a 20-foot c y a n o s i l i c o n e c o l u m n a n d e q u i p p e d w i t h a n A e r o g r a p h m o d e l 471 d i g i t a l integrator. T h e o z o n i d e cis-trans ratios r e p o r t e d are t h e result o f several integrations of the G L P C peak areas a n d h a v e a m a x i m u m v a r i a t i o n of ± 0 . 5 % . T h e p u r e 3-heptene experiments w e r e d o n e o n 1 . 0 M solutions i n pentane. T h e p u r e 3-hexene experiments w e r e d o n e o n 0 . 5 M solutions i n pentane. T h e m i x e d hexene a n d octene experiments w e r e d o n e o n p e n tane solutions w h i c h w e r e 0 . 5 M i n each olefin. T h e a d d e d a l d e h y d e experiments w e r e d o n e o n pentane solutions w h i c h w e r e 0 . 5 M i n olefin a n d of v a r y i n g concentrations of t h e a l d e h y d e s . T h e ozonides w e r e i d e n tified as p r e v i o u s l y d e s c r i b e d (11). Ozonide yields were obtained b y c a l i b r a t i n g t h e G L P C peak areas w i t h k n o w n w e i g h t s of t h e ozonides. T h e e l e m e n t a l analysis of hexene-3 o z o n i d e w a s p r e v i o u s l y r e p o r t e d (11). A n a l y s e s f o r heptene-3 a n d octene-4 o z o n i d e w e r e o b t a i n e d . A n a l y s i s : C a l c u l a t e d f o r C H 0 < : C , 57.51; H , 9.65; O , 32.84. F o u n d : C , 57.67; H , 9.63; O , 32.91. C a l c u l a t e d f o r C H 0 * : C , 59.98; H , 10.07; O , 29.96. F o u n d : C , 60.24; H , 10.15; O , 30.20. 7

1 4

:

8

Results and

1 6

"Discussion

W e h a v e o z o n i z e d mixtures of 4-octene a n d 3-hexene as w e l l as 3-heptene, a n d e x a m i n e d o z o n i d e cis-trans ratios a n d y i e l d s .

F o r mix

tures a l l possible c o m b i n a t i o n s of the cis a n d trans isomers of 3-hexene a n d 4-octene w e r e u s e d , a n d b o t h t h e cis a n d trans isomers of 3-heptene w e r e o z o n i z e d . 3 - H e p t e n e o z o n i d e w a s p r e p a r e d also b y o z o n i z i n g t h e

Mayo; Oxidation of Organic Compounds Advances in Chemistry; American Chemical Society: Washington, DC, 1968.

34

OXIDATION

OF

ORGANIC

COMPOUNDS

III

cis a n d trans isomers of 3-hexene a n d 4-octene i n the presence of the r e q u i r e d aldehyde—i.e.,

b u t y r a l d e h y d e or p r o p i o n a l d e h y d e .

T h e ozonolysis of mixtures of 3-hexene a n d 4-octene does

indeed

g i v e 3-heptene o z o n i d e , i n a d d i t i o n to the ozonides of 3-hexene 4-octene.

and

E x p e r i m e n t s w e r e t h e n d e s i g n e d to d e t e r m i n e the effect of

olefin geometry i n the 3-hexene a n d 4-octene o n the 3-heptene o z o n i d e cis-trans ratio. T h e y i e l d s a n d cis-trans ratios of 3-heptene o z o n i d e f r o m 10 different sources are g i v e n i n T a b l e I. I n these experiments the p u r e 3-heptene reactions w e r e c a r r i e d out at 1 . 0 M , w h i l e the p u r e 3-hexene runs w e r e m a d e at 0 . 5 M .

W h e r e m i x t u r e s of olefins w e r e u s e d ,

the

s o l u t i o n was 0 . 5 M i n e a c h olefin. I n the o l e f i n - a l d e h y d e experiments the


concentrations w e r e 0.5 a n d 0 . 2 5 M f o r olefin a n d a l d e h y d e , r e s p e c t i v e l y . CH CH CH=CHCH CH 3

2

2

+ CH CH CH CH=CHCH CH CH ,

a

H

2

2

2

O—O /

— C H C H C H 3

2

;

0

3

O—O \

/

\

^ C H C H C H , + CH ,CH CH

2

+

2

:

:

+ CH CH CH CH 3

CHCH CH CH

2

2

2

/

o—o

2

2

H

\

^CHCH CH CH 2

2

C l e a r l y the 3-heptene o z o n i d e cis-trans ratio d e p e n d s o n the o r i g i n of the o z o n i d e . W h e n b o t h the 3-hexene a n d the 4-octene h a v e the cis c o n f i g u r a t i o n , t h e n the 3-heptene o z o n i d e p r o d u c e d has a h i g h e r per centage cis o z o n i d e t h a n w h e n b o t h olefins are trans. W h e n the 3-hexene a n d 4-octene are of different configurations, the 3-heptene o z o n i d e cistrans ratio falls b e t w e e n those f o r the a l l cis a n d a l l trans cases.

The

3-heptene o z o n i d e f r o m the parent olefins shows the same t r e n d seen earlier i n a series of olefins—i.e., the cis olefin gives a h i g h e r percentage cis o z o n i d e t h a n the trans isomer.

It is significant that the c o m b i n a t i o n

of cis-3-hexene a n d cis-4-octene gives a h i g h e r percentage cis-3-heptene ozonide (58%)

t h a n does cis-3-heptene itself

C H C H C H = C H C H C H C H ~h O3 3

2

2

/ + CH CH CH 3

2

2

3

(52%).

O-^O / \ • CH CHoCH ^ .^CHCH CH 3

2

3

O—C> O—O X / \ ^ C H C H C H C H + CH CH CH CH CHCH CH CH V

2

2

3

3

2

2


2

2

3

H

62.

MURRAY

35

CrOSS OzOTlideS

AND WILLIAMS

T o determine what mechanistic

pathways might be operating

to

a c c o u n t f o r the different cis-trans ratios, w e h a v e o z o n i z e d the olefin stereoisomers

i n the presence of the respective, necessary a l d e h y d e s . O—o

CH CH CH=CHCH CH + CH CH CH CHO + 0 3

2

2

3

3

2

2

—-

3

CH CH CH^ 3

2

J^CHCH CH 2

3

o— o

CH CH CH CH=CHCH CH CH + CH CH CHO + O


3

—

2

2

2

CH CHXH CH 3

2

2

3

3

2

a

CHCH CH CH + CH CH CH CH ' 2

2

3

3

2

2

J, C H C H C H 2

3

T a b l e I shows that the olefin stereoisomers also give different 3-heptene o z o n i d e cis-trans ratios w h e n they react w i t h the a l d e h y d e o n l y .

The

greatest difference is i n the hexenes w h e r e the cis isomer gives m - 3 - h e p t e n e o z o n i d e i n this r e a c t i o n , whereas

the trans isomer

52% gives

o n l y 4 0 % cis-3-heptene o z o n i d e . W h e n the 3-heptene o z o n i d e cis-trans ratios f r o m the a l l cis olefin p a i r a n d the cis olefins p l u s a l d e h y d e experiments are c o m p a r e d , the a l l cis

olefin p a i r gives a h i g h e r percentage cis-3-heptene o z o n i d e .

Thus,

cis-3-hexene p l u s cis-4-octene gives 3-heptene o z o n i d e w i t h a 58:42 cistrans

ratio whereas

cw-3-hexene

plus butyraldehyde

gives

3-heptene

o z o n i d e w i t h a ratio of 52:48 ( c i s - t r a n s ) , a n d cis-4-octene p l u s p r o p i o n a l d e h y d e gives a ratio of 49:51

(cis-trans).

W h e n a similar comparison

is m a d e for the same experiment u s i n g the trans olefin isomers, the s y m m e t r i c a l olefin p a i r gives a 3-heptene o z o n i d e cis-trans ratio w h i c h is b e t w e e n that o b t a i n e d i n the t w o o l e f i n - a l d e h y d e experiments. W e have also e x a m i n e d the y i e l d s , a n d for 3-hexene the

ozonide

cis-trans ratio, i n the s y m m e t r i c a l ozonides w h i c h result f r o m the v a r i o u s reaction conditions used (Table I I ) .

U n f o r t u n a t e l y , w e w e r e not

to get r e l i a b l e cis-trans ratio d e t e r m i n a t i o n s

able

for the 4-octene o z o n i d e

because of the p o o r r e s o l u t i o n of this p a i r o n the G L P C c o l u m n . H e r e a g a i n , the 3-hexene o z o n i d e cis-trans

ratio d e p e n d s

on

the

o r i g i n of the o z o n i d e . T h e same g e n e r a l observations that w e r e f o u n d for 3-heptene o z o n i d e also a p p l y here.

T h u s , the all-cis olefin p a i r gives a

h i g h e r percentage cis-3-hexene o z o n i d e t h a n the all-trans p a i r , w h i l e the t w o m i x e d isomer pairs give ratios w h i c h f a l l b e t w e e n those for the all-cis a n d all-trans cases.


36

OXIDATION

Table I.

OF ORGANIC

COMPOUNDS

III

3-Heptene Ozonide cis-trans


Source

/

y/\

\

y / \ — \

/

\

—

+ CH CH CH CHO 3

2

2

+ CH CH CH CHO 3

/

\

/

2

2

+ CH CH CHO 3

2

+ CH0CH0CHO

Some

significant observations

regarding the yields can be made.

T a b l e s I a n d I I s h o w that t h e cis isomers consistently g i v e a h i g h e r total o z o n i d e y i e l d t h a n the trans isomers. T h i s is true f o r t h e i n d i v i d u a l olefins as w e l l as f o r t h e pairs of l i k e stereochemistry.

It is e v e n true w h e n the

i n d i v i d u a l olefins are o z o n i z e d i n t h e presence of a f o r e i g n a l d e h y d e . T h i s observation is consistent w i t h those m a d e earlier ( 5 , 9, 11, 14), a l l of w h i c h i n d i c a t e that cis isomers i n v a r i a b l y give a h i g h e r o z o n i d e y i e l d . T h i s is o n l y one of several factors w h i c h suggest that there is a f u n d a m e n t a l difference i n the m e c h a n i s m of ozonolysis b e t w e e n m a n y , if n o t a l l , cis a n d trans olefin isomers. W h i l e t h e experiments w i t h a d d e d f o r e i g n a l d e h y d e i n T a b l e I w e r e d e s i g n e d to test m e c h a n i s t i c possibilities, s u c h a n i n t e r p r e t a t i o n is c o m p l i c a t e d b y the fact that these a l d e h y d e s cannot

o n l y enter into the

c h e m i s t r y of t h e ozonolysis process b u t m a y also exert a m e d i u m effect since they are c o n s i d e r a b l y m o r e p o l a r t h a n the pentane solvent.


It is

62.

MURRAY

Cross

AND WILLIAMS

37

Ozonides

Ratios and Yields from Various Sources 3-Heptene Ozonide


% cis

% trans

„ \ Ozonide, T

o

t

a

% Total Ozonide

% Yield

58

42

23

97

44

56

20

43

51

49

16

97

51

49

20

66

52

48

81

82

42

58

80

39

52

48

32

89

40

60

30

65

49

51

40

90

46

54

42

60

possible, therefore,

that the ozonolysis m e c h a n i s m i n the presence

added a l d e h y d e is different f r o m that w h e r e olefins alone are u s e d .

of

That

this m e d i u m effect does i n fact o c c u r c a n be seen b y e x a m i n i n g the a l d e h y d e experiments i n T a b l e II.

H e r e , for 3-hexene p l u s b u t y r a l d e -

h y d e , for e x a m p l e , the 3-hexene o z o n i d e cis-trans ratio o b t a i n e d f r o m cis-3-hexene is different f r o m that o b t a i n e d f r o m this same olefin i n p e n t a n e s o l u t i o n alone. A m u c h l o w e r p e r c e n t a g e cis o z o n i d e is o b t a i n e d i n the e x p e r i m e n t w i t h the a d d e d a l d e h y d e . Since b u t y r a l d e h y d e cannot p a r t i c i p a t e c h e m i c a l l y i n the 3-hexene o z o n i d e f o r m a t i o n , the change i n the o z o n i d e cis-trans ratio m u s t b e a m e d i u m effect of the

aldehyde.

T h e t e r m m e d i u m effect is u s e d here to describe a l l possible effects of the f o r e i g n a l d e h y d e on the p r o d u c t i o n of the n o r m a l o z o n i d e of olefin b e i n g o z o n i z e d .

the

T h i s w o u l d i n c l u d e p o l a r i t y effects, s o l v a t i o n

effects, perhaps assisted d e c o m p o s i t i o n of ozone-olefin a d d u c t s , a n d selec t i v e d i v e r s i o n of the n o r m a l o z o n i d e precursors i n s u c h a w a y that the o z o n i d e cis-trans r a t i o is a l t e r e d .


38

OXIDATION

Table II.

O F ORGANIC

COMPOUNDS

III

3-Hexene Ozonide cis-trans Ratios and


Source

+ CHoCH CHoCHO 9

/ \

y ^ /

\ / \ — / \ /

+ CH CH CH CHO 3

2

2

+ CH CH CHO 3

2

+ CH CH CHO 3

n

2

Reliable ozonide cis-trans ratios for 4-octene ozonide not yet available.

Medium Effect of Added Aldehyde. T o examine f u r t h e r the m e d i u m effect of a d d e d a l d e h y d e w e o z o n i z e d 0 . 5 M solutions of cis- a n d trans-3hexene c o n t a i n i n g v a r y i n g concentrations of b u t y r a l d e h y d e a n d deter m i n e d t h e o z o n i d e cis-trans ratios a n d y i e l d s f o r b o t h the 3-hexene a n d


62.

MURRAY

39

Cross Ozouides

AND WILLIAMS

3-Hexene and 4-Octene Ozonide Yields from Various Sources 3-Hexene Ozonide


% cis

% trans

% of Total

4-Octene Ozonide,"

, 1 otal Ozonide,

Ozonide

% of Total Ozonide

% Yield

53

47

49

28

97

43

57

50

30

43

51

49

67

17

97

44

56

36

44

66

56

44

12

7

82

43

57

15

5

39

49

51

68

—

89

43

57

70

—

65

—

—

—

60

90

—

—

—

58

60

57

43

100

—

90

44

56

100

—

49

3-heptene ozonides p r o d u c e d . T h e effect of b u t y r a l d e h y d e c o n c e n t r a t i o n o n the 3-hexene o z o n i d e cis-trans ratio is s h o w n i n F i g u r e 1. T h e a d d e d a l d e h y d e has h a d a p r o n o u n c e d effect o n the o z o n i d e cis-trans

ratio

o b t a i n e d f r o m the cis olefin isomer a n d o n l y a slight effect i n the case of the trans isomer.

F o r the cis isomer, i n c r e a s i n g the c o n c e n t r a t i o n


of

40

OXIDATION

butyraldehyde

causes

o z o n i d e u n t i l ca.

a n increase

O F ORGANIC

COMPOUNDS

i n the percentage

III

£rans-3-hexene

1 . 0 M a l d e h y d e c o n c e n t r a t i o n is r e a c h e d , w h e r e the

r a t i o stays f a i r l y constant w i t h i n c r e a s i n g a l d e h y d e c o n c e n t r a t i o n .

In

the trans case the 3-hexene o z o n i d e cis-trans r a t i o stays f a i r l y constant t h r o u g h o u t t h e r a n g e of a l d e h y d e concentrations a l t h o u g h there is a slight increase i n t h e percentage trans o z o n i d e at a l d e h y d e concentrations a b o v e 1 . 0 M . T h e final o z o n i d e cis-trans ratios r e a c h e d at h i g h a l d e h y d e concentrations are a p p r o x i m a t e l y t h e same f o r t h e cis a n d trans olefin isomers.


65 |

1

Figure 1. 3-Hexene ozonide cis-trans ratios as a function of added butyraldehyde concentration in the ozonolysis of cis- and trans-3-hexene A s o m e w h a t s i m i l a r effect occurs i n t h e 3-heptene o z o n i d e as s h o w n i n F i g u r e 2. H e r e a g a i n the £rans-3-hexene, o z o n i z e d i n t h e presence of b u t y r a l d e h y d e , gives a b o u t t h e same 3-heptene at a l l b u t y r a l d e h y d e concentrations.

o z o n i d e cis-trans r a t i o

A slight increase i n the percentage

trans o z o n i d e does o c c u r at a l d e h y d e concentrations a b o v e 1 . 0 M . T h e cis-3-hexene case shows a n i n c r e a s i n g percentage £rans-3-heptene o z o n i d e w i t h i n c r e a s i n g b u t y r a l d e h y d e c o n c e n t r a t i o n u n t i l the a l d e h y d e c o n c e n t r a t i o n reaches a b o u t 2 . 0 M , after w h i c h the ratio r e m a i n s f a i r l y constant. T h e final o z o n i d e cis-trans ratios r e a c h e d f o r the 3-heptene case, h o w e v e r , are different f o r t h e t w o 3-hexene stereoisomers w i t h t h e cis isomer g i v i n g a h i g h e r percentage cis o z o n i d e . S i m i l a r differences f o r the olefin stereoisomers are seen i n t h e y i e l d d a t a s h o w n i n F i g u r e s 3 a n d 4. F o r cis-3-hexene t h e t o t a l o z o n i d e y i e l d r e m a i n s f a i r l y constant a n d h i g h t h r o u g h o u t ( F i g u r e 3 ) .

I n fact, t h e


62.

MURRAY

Cross

ANDWILLIAMS

41

Ozonides

65

3

UJ

-o

-o

o

|60 o

-a

55

O TRANS-3-HEXENE • CIS-3-HEXENE CO

z
v

2 *—O

o

'

0

1

1/4

1

1/2

1 1

CONCENTRATION

1

2

O 1

3

OF B U T Y R A L D E H Y D E - M O L E S / L I T E R

Figure 4. Variation of 3-hexene ozonide yield, 3-heptene ozonide yield, and total ozonide yield as a function of added butyraldehyde concentration in the ozonolysis of trans-3-hexene


44

OXIDATION

y i e l d r e m a i n i n g f a i r l y constant.

OF

ORGANIC

COMPOUNDS

A t h i g h e r a l d e h y d e concentrations

III

it

becomes m o r e difficult to d i v e r t a n y m o r e precursors perhaps because of t i g h t cage reactions, a n d the 3-hexene o z o n i d e y i e l d c u r v e has a r e d u c e d slope. T h e s l i g h t l y r e d u c e d t o t a l o z o n i d e y i e l d at h i g h e r a l d e h y d e c o n centrations c o u l d reflect the greater t e n d e n c y to f r a g m e n t a t i o n

reactions

of the ozone-olefm a d d u c t a n d the expected a c c o m p a n y i n g increase i n side reactions. I n the trans case, h o w e v e r , it is clear f r o m F i g u r e 4 that s o m e t h i n g e n t i r e l y different is h a p p e n i n g . H e r e a d d i t i o n of the b u t y r a l d e h y d e has a c t u a l l y increased the t o t a l o z o n i d e y i e l d . T h e e x p l a n a t i o n for this p r o b a b l y lies i n the suggestion m a d e earlier that cis a n d trans olefins c a n


h a v e different ozonolysis m e c h a n i s m s .

It is interesting to r e c a l l t h a t w h i l e

there have b e e n several reports (1, 3, 6)

of the f o r m a t i o n of a p r i m a r y

o z o n i d e , w h i c h is stable at l o w temperatures, for trans olefins, cis olefins a p p a r e n t l y g i v e n o s u c h p r i m a r y o z o n i d e or one of c o m p l e t e l y different nature and stability. A s stated earlier, it is p r o p o s e d that the trans case is m o r e l i k e l y to i n v o l v e f r a g m e n t a t i o n after f o r m a t i o n of the i n i t i a l olefin-ozone a d d u c t . I n the absence of a d d e d a l d e h y d e , a c e r t a i n percentage of these fragments c o m b i n e i n a cage, others w a n d e r out of the cage a n d t h e n r e c o m b i n e , w h i l e still others w a n d e r to the extent that they stand a p o o r e r c h a n c e of g i v i n g o z o n i d e a n d m a y e n d u p as n o n - o z o n i d e p r o d u c t s .

In

the

presence of a d d e d a l d e h y d e m o r e of the fragments w h i c h h a v e left the cage c a n be c o n v e r t e d to o z o n i d e , albeit a n e w o z o n i d e , a n d the o v e r - a l l o z o n i d e - f o r m i n g process is m a d e m o r e efficient.

T h e f a c t that the y i e l d

of 3-hexene o z o n i d e is r e d u c e d far less t h a n the g a i n i n y i e l d of 3-heptene o z o n i d e also suggests that m a n y p o t e n t i a l o z o n i d e precursors w o u l d not h a v e g i v e n o z o n i d e i n the absence of a d d e d a l d e h y d e . A s the b u t y r a l d e h y d e c o n c e n t r a t i o n increases, constant,

non-zero value.

the y i e l d of 3-hexene o z o n i d e reaches a

T h i s v a l u e m a y represent

3-hexene o z o n i d e

f o r m a t i o n w h i c h occurs i n a t i g h t cage w h i c h the a d d e d a l d e h y d e cannot penetrate even at f a i r l y h i g h

concentrations.

W e are still not able to discuss a n o v e r - a l l ozonolysis m e c h a n i s m i n a n y specific, d e t a i l e d w a y . Instead w e s t i l l must settle for b r o a d e r gen eralizations a n d p o s t u l a t e d intermediates w h i c h are g i v e n properties to r a t i o n a l i z e the e x p e r i m e n t a l results.

S t i l l as a result of c o n t i n u e d e x p e r i

m e n t a t i o n there are clear differences differences

between

a p p e a r i n g , s u c h as the o v e r - a l l

cis a n d trans olefins.

F u r t h e r w o r k a n d n e w ap

proaches m a y s h e d f u r t h e r l i g h t o n this a p p a r e n t l y c o m p l e x process.

Literature Cited

(1) Bailey, P. S., Thompson, J. A., Shoulders, B. A., J. Am. Chem. Soc. 88, 4098 (1966). (2) Criegee, R., Record Chem. Progr. 18, 111 (1957).


62.

(3) (4) (5) (6) (7) (8) (9) (10) (11) (12) (13)


(14) (15)

MURRAY

AND

WILLIAMS

Cross

Ozonides

45

Criegee, R., Schröder, Chem. Ber. 93, 689 (1960). Criegee, R., Bath, S. S., Bornhaupt, B. V., Chem. Ber. 93, 2891 (1960). Greenwood, F. L., J. Am. Chem. Soc. 88, 3146 (1966). Greenwood, F. L., Haske, B. J., Tetrahedron Letters 1965, 631. Kolsaker, P., Acta. Chem. Scand. 19, 223 (1965). Loan, L. D., Murray, R. W., Story, P. R., J. Am. Chem. Soc. 87, 737 (1965). Lorenz, O., Parks, C. R., J. Org. Chem. 30, 1976 (1965). Murray, R. W., Youssefyeh, R. D., Story, P. R., J. Am. Chem. Soc. 88, 3143 (1966). Ibid., 89, 2429 (1967). Privett, O. S., Nickell, E. C., J. Am. Oil Chemists Soc. 41, 72 (1964). Riezebos, G., Grimmelikhuysen, J. C., Van Dorp, D. A., Bee. Trav. Chim. 82, 1234 (1963). Schröder, G., Chem. Ber. 95, 733 (1962). Story, P. R., Murray, R. W., Youssefyeh, R. D., J. Am. Chem. Soc. 88, 3144 (1966).

RECEIVED

October 18,

1967.


Cross Ozonides from Pairs of Symmetrical Olefins - Advances in

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