The Ozonolysis of Organomercurials - Advances in Chemistry (ACS

7 The Ozonolysis of Organomercurials WILLIAM

L. WATERS,

PAUL E. PIKE, and JOSEPH G. RIVERA

Downloaded by UNIV OF MINNESOTA on August 28, 2013 | http://pubs.acs.org Publication Date: June 1, 1972 | doi: 10.1021/ba-1972-0112.ch007

University of Montana, Missoula, Mont. 59801

The

reaction

curials

of ozone

with

and alkylmercuric

carboxylic ondary,

acids,

ketones,

and tertiary

carbon—mercury

conditions

was the

cleavage

four-center

processes.

from

primary,

respectively. chief

of sec

Although reaction,

did occur in varying

degrees.

course

under pseudo first-order of positive

step.

is depicted

dialkylmer-

good yields

of

a build-up

in the rate-determining -mercury cleavage ozonolysis

and alcohols

study of the reaction indicated

produced

alkylmercurials,

scission

some carbon—carbon A kinetic

over 20 different

halides

The

mechanism

as a mixture

Although

of organomercurials

charge

somewhat does promise

on

for

carbon

of pure limited

rate carbon

S2 E

in

synthetic

and

scope, utility.

Τ η t h e s e a r c h for n e w s y n t h e t i c uses of o r g a n o m e r c u r i a l s a n d t h e olefin A

m e r c u r a t i o n reactions i n g e n e r a l , a t t e n t i o n w a s d r a w n to o z o n e as a

p o s s i b l e reactant. O r g a n o m e r c u r i a l s r e a c t r a p i d l y w i t h a v a r i e t y of e l e c t r o p h i l i c spe cies, a n d a recent b o o k b y J e n s e n a n d R i c k b o r n f u l l y describes the scope of these reactions ( I ) .

F o r e m o s t a m o n g the e l e c t r o p h i l i c reagents are

the halogens w h i c h cleave the carbon—mercury b o n d to p r o d u c e a l k y l m e r c u r i c h a l i d e s a n d / o r a l k y l h a l i d e s , d e p e n d i n g o n the t y p e of o r g a n o mercurial involved. fast

R Hg + Br 2

• RBr + RHgBr

2

^

slower

RHgBr + Br

> RBr +

2

HgBr

2

I n a d d i t i o n , p r o t i c acids also cleave o r g a n o m e r c u r i a l s to y i e l d the p r o t o n s u b s t i t u t e d p r o d u c t s analogous to those for h a l o g e n a t i o n above.

Finally,

m e r c u r i c salts also act as e l e c t r o p h i l i c reagents t o w a r d s o r g a n o m e r c u r i a l s . 78 In Ozone Reactions with Organic Compounds; Bailey, P.; Advances in Chemistry; American Chemical Society: Washington, DC, 1972.

7.

Ozonolysis

WATERS E T A L .

R Hg + 2

RHgBr +

of

HgBr

*HgBr

2RHgBr

2

R*HgBr +

2

where * H g = Several mechanisms c l e a v a g e reactions.

have

79

Organomercurials

been

203

HgBr

(2)

2

Hg

proposed

for

these

electrophilic

I n g e n e r a l , these m e c h a n i s m s r a n g e f r o m p u r e

S 1 E

to p u r e S 2 processes a l t h o u g h these t w o extreme m e c h a n i s m s are u s u a l l y E


r e s e r v e d f o r s p e c i a l cases.

R Hg +

S l: B

2

Y

R +

-» R — H g — R

RHgY

I

γ

(3)

X

RX R Hg +

Sd:

2

R—Hg—R

X — Y

•R

Χ—Y

Hg—R

X — Y

RX +

+

(4)

YHgR

R Four-Center

: R Hg + Χ—Y

>R

2

>R X + YHgR

H£

(5)

X S 2: E

R Hg + 2

R—X—Y

R—Hg—R

X — Y

X—Y

H g - R

RX +

(6)

YHgR

O z o n e has l o n g b e e n assigned the r o l e of e l e c t r o p h i l e i n a d d i t i o n a n d s u b s t i t u t i o n reactions

(2).

I n this respect the reagent has

r e p o r t e d to cleave v a r i o u s c a r b o n - m e t a l b o n d s

(Et) Sn 4

0

3

AcH +

been

(3-9).

( E t ) S n O + a peroxide 2

In Ozone Reactions with Organic Compounds; Bailey, P.; Advances in Chemistry; American Chemical Society: Washington, DC, 1972.

(7)

80

OZONE REACTIONS WITH ORGANIC COMPOUNDS

(Et) Pb

(Et) PbOH +

4

3

20°

+ AcH + Os

( E t ) «Si

AcOH + H 0 2

0

R Se

3

2

+ Et Si0 H + 3

2

0

3

2

RSeH +

2

(t-Pr) Hg

3

(8)

EtOH

R SeO

2


2

(Et) PbO + (Et) PbOEt

2(CH ) CO + 3

2

(Et Si) 0 3

2

aldehyde

HgO

(9)

(10)

(11)

A l t h o u g h reports of m e c h a n i s t i c studies are scarce f o r these reac tions, O u e l l e t t e a n d M a r k s d i d p r o p o s e a 1,3-dipolar attack b y ozone (10). T h e c o r r e s p o n d i n g i n t e r m e d i a t e w a s p r e d i c t e d to be a h y d r o t r i o x i d e of s i l i c o n .

-H R —Si 3

Ο-

-ο

/

Ο

->

[R —Si—Ο—Ο—OH] 3

(12)

T h e u n s t a b l e h y d r o t r i o x i d e c o u l d t h e n d e c o m p o s e via singlet or t r i p l e t o x y g e n ejection to f o r m the o b s e r v e d s i l a n o l p r o d u c t s The

(10).

Reaction

T h e cleavage of c a r b o n - m e t a l b o n d s b y o z o n e is i n t r i g u i n g . S t u d y was b e g u n to discover the scope of this r e a c t i o n u s i n g m e r c u r i a l s as the o r g a n o m e t a l l i c reagent. I t w a s h o p e d t h a t n o t o n l y w o u l d the cleavage m e c h a n i s m be c l a r i f i e d b u t also that a s y n t h e t i c a l l y u s e f u l m e t h o d of i n t r o d u c i n g o x y g e n f u n c t i o n a l i t y m i g h t be d e v e l o p e d . O z o n a t i o n of over 20 different o r g a n o m e r c u r i a l s r e s u l t e d i n a f a i r l y r a p i d d i s a p p e a r a n c e of o r g a n o m e t a l l i c s t a r t i n g m a t e r i a l , a c c o m p a n i e d b y a constant p r e c i p i t a t i o n of i n o r g a n i c m e r c u r y salts. A p r o d u c t s t u d y i n c h l o r o f o r m a n d m e t h y l e n e c h l o r i d e solvents at temperatures r a n g i n g f r o m —75° to + 2 5 ° C s h o w e d that m e r c u r y was r e p l a c e d b y a n o x y g e n c o n t a i n i n g m o i e t y i n a l l cases (11). A l t h o u g h these p r o d u c t s w e r e chiefly the analogous a l c o h o l , ketone, or a c i d f r o m the p a r e n t 3 ° , 2 ° , or 1° o r g a n o m e r c u r i a l r e s p e c t i v e l y , some c a r b o n - c a r b o n scission d i d occur.


7.

WATERS E T A L .

Ozonolysis

of

81

Organomercurials

T h i s was e s p e c i a l l y e v i d e n t at the h i g h e r temperatures a n d i n the case of the a l k y l m e r c u r i c h a l i d e s . A k i n e t i c s t u d y of the r e a c t i o n w a s also p e r f o r m e d i n w h i c h N M R o b t a i n e d rate d a t a w e r e c o r r e l a t e d w i t h m e r c u r i a l s t r u c t u r e changes

(12).

This study revealed a quite distinct reactivity order w h i c h , coupled w i t h a 1:1 reactant s t o i c h i o m e t r y , i n d i c a t e s a 1,3-dipolar e l e c t r o p h i l i c attack b y o z o n e via SL S 2 or four-center process. e

A l t h o u g h the exact m e c h a n i s m

was n o t c o n c l u s i v e l y p r o v e d , it is c e r t a i n that n e i t h e r the S 1 or S i E

E


processes w e r e o p e r a t i v e d u r i n g these reactions. Experimental Materials. G e n e r a l l y t h e o r g a n o m e r c u r i c h a l i d e s w e r e p r e p a r e d u s i n g the G r i g n a r d m e t h o d as o u t l i n e d b y M a r v e l et al. (13). The dialkylm e r c u r i a l s w e r e also s y n t h e s i z e d b y the G r i g n a r d p r o c e d u r e as o u t l i n e d b y G i l m a n a n d B r o w n (14). E x a c t s t r u c t u r a l i d e n t i f i c a t i o n of the o r g a n o m e r c u r i a l s was f a c i l i t a t e d b y c o r r e l a t i o n of N M R - o b t a i n e d Hg- H s p i n - s p i n c o u p l i n g d a t a w i t h l i t e r a t u r e values for s i m i l a r systems ( 1 5 , 1 6 ) . P r e l i m i n a r y i d e n t i f i c a t i o n was p e r f o r m e d b y the u s u a l c o m p a r i s o n of p h y s i c a l properties w i t h those for k n o w n c o m p o u n d s . Apparatus. T h e a p p a r a t u s u s e d i n these studies consisted of a W e l s b a c h T - 4 0 8 e l e c t r i c d i s c h a r g e o z o n a t o r c o n n e c t e d to three 2 0 0 - m l gas w a s h i n g bottles i n series. T h e first bottle w a s the r e a c t i o n vessel, a n d its t e m p e r a t u r e was m a i n t a i n e d at — 7 6 ° , 0 ° , or + 1 0 ° C . T h e s e c o n d b o t t l e was a c o l d t r a p for t h e m o r e v o l a t i l e products—e.g., a c e t o n e — w h i c h w e r e g e n e r a l l y s w e p t out of the r e a c t i o n vessel b y the l a r g e v o l u m e of 0 . T h e t h i r d b o t t l e c o n t a i n e d a n aqueous K I s o l u t i o n for t r a p p i n g a n y u n r e a c t e d 0 . A f t e r c o m p l e t i o n of a r e a c t i o n this s o l u t i o n c o u l d b e t i t r a t e d w i t h t h i o s u l f a t e f o r l i b e r a t e d I a n d thus u n r e a c t e d 0 . B y u s i n g Ο as the f e e d gas, a n 0 - 0 m i x t u r e , 3 - 4 % 0 b y w e i g h t , was p r o d u c e d b y the ozonator. F l o w rates w e r e adjusted to p r o d u c e 1 8 - 3 0 m m o l e s of 0 p e r h o u r . F o r the rate studies the a b o v e - m e n t i o n e d r e a c t i o n vessel was m o d i f i e d to a l l o w for r a p i d a n d p e r i o d i c r e m o v a l of s o l u t i o n a l i q u o t s d u r i n g the progress of the r e a c t i o n . 1 9 9

1

2

3

2

2

3

3

2

3

3

Procedure. P R O D U C T - D E T E R M I N I N G STUDIES. I n a t y p i c a l p r o d u c t d e t e r m i n i n g r u n 10 m m o l e s of o r g a n o m e r c u r i a l w e r e d i s s o l v e d i n ca. 50 m l of C H C 1 a n d p l a c e d i n the r e a c t i o n vessel. A f t e r the vessel w a s c o o l e d to the p r o p e r t e m p e r a t u r e , the 0 - 0 flow w a s started. I n a l l cases a n i m m e d i a t e w h i t e p r e c i p i t a t e a p p e a r e d . T h i s p r e c i p i t a t i o n was constant t h r o u g h o u t the entire ozonolysis p r o c e d u r e a n d i n fact w a s u s e d as a n e n d p o i n t d e t e r m i n a n t i n c e r t a i n cases. O z o n a t i o n w a s g e n e r a l l y h a l t e d after a l l of the o r g a n o m e r c u r i a l h a d r e a c t e d . T h e r e s u l t a n t w h i t e s o l i d was t h e n c o l l e c t e d , w a s h e d w i t h C H C 1 , d r i e d , a n d subjected to analysis b y p o w d e r x - r a y d i f f r a c t i o n w i t h a N o r e l c o a n a l y t i c a l x - r a y diffractometer. T h e C H C 1 s o l u t i o n was a n a l y z e d b y v a p o r phase c h r o m a t o g r a p h y (VPC) m e t h o d s u s i n g 6 ft X % i n c h 3 0 % C a r b o w a x or 6 ft X % i n c h 2 0 % S E - 3 0 c o l u m n s . R e t e n t i o n times of the r e a c t i o n p r o d u c t s w e r e m a t c h e d o n b o t h c o l u m n s w i t h p r e c a l i b r a t e d c h r o m a t o g r a p h s of k n o w n 2

2

3

2

2

2

2

2


82

OZONE REACTIONS W I T H ORGANIC COMPOUNDS

c o m p o u n d s . A n i n t e r n a l s t a n d a r d w a s a d d e d to the C H C 1 i n t e g r a t i o n purposes. 2

s o l u t i o n for

2

K I N E T I C STUDIES. I n a t y p i c a l k i n e t i c r u n 10 m m o l e s of o r g a n o m e r c u r i a l w e r e d i s s o l v e d i n 100 m l of C H C 1 a n d p l a c e d i n the r e a c t i o n vessel. T o this s o l u t i o n w e r e a d d e d 30 m m o l e s of C H N 0 as a n i n t e r n a l N M R s t a n d a r d . O z o n e flow rates w e r e d e t e r m i n e d a n d the m e r c u r i a l solution w a s t h e n o z o n i z e d at 0 ° C . A l i q u o t s w e r e p e r i o d i c a l l y w i t h d r a w n ( g e n e r a l l y , 8 - 1 0 samples t a k e n ) a n d s h a k e n w i t h a s o l i d m i x t u r e of ca. 0.1 g r a m K I a n d 0.1 g r a m N a S 0 . I n this m a n n e r excess 0 w a s i m m e d i a t e l y q u e n c h e d a n d the r e s u l t a n t I , w h i c h itself reacts w i t h o r g a n o m e r c u r i a l s at r o o m t e m p e r a t u r e , w a s q u i c k l y r e d u c e d . 3

3

2

2

2

3

3


2

E a c h a l i q u o t was a n a l y z e d w i t h o u t f u r t h e r w o r k - u p b y a n H A - 6 0 A n a l y t i c a l N M R S p e c t r o m e t e r , u s i n g the field s w e e p m e t h o d to e l i m i n a t e the u s u a l phase changes associated w i t h the f r e q u e n c y s w e e p m o d e . T h e r e l a t i v e integrals for C H N 0 a n d one set of resonance lines for the o r g a n o m e r c u r i a l w e r e r e p e a t e d 10 t i m e s a n d averaged. T h i s average v a l u e w a s c o m p a r e d w i t h the o r i g i n a l C H N 0 / o r g a n o m e r c u r i a l r a t i o to d e t e r m i n e the c o n c e n t r a t i o n of o r g a n o m e r c u r i a l at that t i m e . T h e s e a c t u a l concentrations, a l o n g w i t h the respective t i m e intervals f r o m f , w e r e s u b m i t t e d to a least-squares c o m p u t e r p r o g r a m . U s i n g a n I B M 1620 c o m p u t e r , the n a t u r a l l o g a r i t h m of t h e c o n c e n t r a t i o n w a s p l o t t e d vs. t i m e (ca. 10 p o i n t s ) to g i v e the best-fitting l i n e a r r e l a t i o n s h i p b e t w e e n the t w o v a r i a b l e s . F r o m this p l o t the least-squares slope, (/-intercept, absolute rate constant, a n d c o r r e l a t i o n coefficient of the l i n e w e r e determined. 3

2

3

2

0

O T H E R STUDIES. C e r t a i n ozonations w e r e c a r r i e d out u s i n g N as the c a r r i e r gas i n s t e a d of 0 . F o r these reactions the u s u a l s i l i c a g e l p r o c e d u r e (17) was u s e d . S i l i c a gel, 1 0 0 - 1 5 0 grams, 6 - 1 2 m e s h , w a s p l a c e d i n a 2 0 0 - m l s i d e - a r m c o l d t r a p a n d c o o l e d to — 76 ° C . O z o n e was i n t r o d u c e d i n t o this t r a p as the u s u a l 0 - 0 m i x t u r e . A f t e r the d e s i r e d a m o u n t of 0 h a d b e e n a d s o r b e d b y the s i l i c a g e l , the ozonator was d i s c o n n e c t e d a n d the c o l d t r a p flushed w i t h a m b i e n t t e m p e r a t u r e N for 5 m i n u t e s to r e m o v e a n y 0 . O z o n e was t h e n flushed s l o w l y f r o m the s i l i c a g e l b y g r a d u a l l y m o v i n g the t r a p v e r y short distances out of the d r y i c e — acetone b a t h w h i l e c o n t i n u i n g to flush w i t h N [ h a s t e n i n g this w a r m i n g procedure resulted i n a violent explosion]. 2

2

3

2

3

2

2

2

N e x t , a s t o i c h i o m e t r i c s t u d y was u n d e r t a k e n to d e t e r m i n e the n u m b e r of moles of 0 w h i c h r e a c t e d w i t h e a c h m o l e of o r g a n o m e r c u r i a l . T o a c c o m p l i s h this task the 0 flow rate was a c c u r a t e l y d e t e r m i n e d b y the K I - N a S 0 p r o c e d u r e . O z o n a t i o n of a m e r c u r i a l i n C H C 1 or C H C 1 w a s t h e n b e g u n . I n c l u d e d i n the r e a c t i o n m i x t u r e was a s m a l l a m o u n t of C H N 0 as a n N M R i n t e g r a t i o n s t a n d a r d . T h e r e a c t i o n w a s s t o p p e d s e v e r a l times to c h e c k the o r g a n o m e r c u r i a l c o n c e n t r a t i o n b y N M R spectroscopy. T h e a m o u n t of u n r e a c t e d o z o n e also h a d to b e c a l c u l a t e d at e a c h s a m p l i n g p e r i o d for the p r i m a r y a n d s e c o n d a r y a l k y l m e r c u r i c h a l i d e s . T h e 0 flow rate w a s also r e c h e c k e d at e a c h s a m p l i n g i n t e r v a l to ensure t h a t the d i s p e r s i o n tubes h a d not c l o g g e d . T h e n u m b e r of moles of r e a c t e d 0 w a s t h e n c o m p a r e d w i t h the n u m b e r of moles of reacted organomercurial. 3

3

2

3

2

3

2

2

2

3

3


3

7.

WATERS E T A L .

Ozonolysis

of

83

Organomercurials

Results Product Studies. T a b l e I outlines t h e o r g a n i c a n d i n o r g a n i c p r o d u c t s of the ozonolysis reactions. T h e ozonolysis p r o d u c t s of n - a l k y l m e r c u r i c h a l i d e s a n d d i - n - a l k y l m e r c u r i a l s w e r e a m i x t u r e of c a r b o x y l i c acids w h i c h h a d a c a r b o n c h a i n e q u a l to or shorter t h a n the a l k y l g r o u p of the p a r e n t organomercurial. O z o n o l y s i s of the s - a l k y l m e r c u r i c h a l i d e s a n d the d i - s - a l k y l m e r c u r i a l s p r o d u c e d the c o r e s p o n d i n g ketone. A l t h o u g h some c a r b o n - c a r b o n c l e a v -


age o c c u r r e d , i t was g e n e r a l l y less t h a n w i t h the r e a c t i o n of the p r i m a r y o r g a n o m e r c u r i a l s (see

R e a c t i o n s 13 a n d 14, T a b l e I ) .

I n p a r t i a l contrast

to the results of B o c k e m u l l e r a n d Pfeuffer ( R e a c t i o n 11),

the ozonation

of d i i s o p r o p y l m e r c u r y y i e l d e d acetic a c i d i n a d d i t i o n to acetone ( R e a c t i o n 14, T a b l e I ) . T e r t i a r y a l k y l m e r c u r i c h a l i d e s y i e l d e d a c o n s i d e r a b l e a m o u n t of the corresponding alcohol upon ozonation

( R e a c t i o n 17, T a b l e I ) .

Some

c a r b o n - c a r b o n cleavage a c c o m p a n i e d the m a i n r e a c t i o n i n this case as well. T h e i n o r g a n i c p r o d u c t s of the ozonolysis reactions w e r e d e t e r m i n e d for three different o r g a n o m e r c u r i a l s .

O z o n o l y s i s of

two

dialykylmer-

c u r i a l s p r o d u c e d a m i x t u r e of m e r c u r i c c h l o r i d e , m e r c u r o u s c h l o r i d e , a n d m e r c u r i c o x i d e ( R e a c t i o n s 3 a n d 14, T a b l e I ) w h i l e one a l k y l m e r c u r i c h a l i d e gave o n l y m e r c u r i c a n d m e r c u r o u s c h l o r i d e s ( R e a c t i o n 13, T a b l e I ) . A k n o w n m i x t u r e of the three salts w a s tested f o r its s t a b i l i t y to the r e a c t i o n c o n d i t i o n s . T h e salts w e r e o z o n i z e d as a s o l u t i o n / m i x t u r e w i t h m e t h y l e n e c h l o r i d e . P o w d e r x - r a y d i f f r a c t i o n s h o w e d n o difference i n the m e r c u r y salt m i x t u r e after a 2-hour o z o n a t i o n at 1 0 ° C . Carbon—Carbon

Cleavage.

As

mentioned

above,

carbon—carbon

cleavage

u s u a l l y a c c o m p a n i e d the " n o r m a l " carbon—mercury

reaction.

W h i l e this c h a i n - s h o r t e n i n g process was most p r o m i n e n t for

the n - a l k y l m e r c u r i c h a l i d e s w h i c h w e r e o z o n a t e d at 1 0 ° C

cleavage

(Reactions 1

a n d 6, T a b l e I ) , i t w a s r e d u c e d to a m u c h l o w e r l e v e l w h e n the d i - n a l k y l m e r c u r i a l s w e r e o z o n a t e d at — 7 6 ° C ( R e a c t i o n s 5 a n d 10, T a b l e I ) . A c t u a l l y e v e n less carbon—carbon scission o c c u r r e d d u r i n g the o z o n a t i o n of the d i - s - a l k y l m e r c u r i a l s h a l i d e s ( R e a c t i o n 14, T a b l e I ) a n d d u r i n g the p a r t i a l o z o n a t i o n of t h e f e r f - a l k y l m e r c u r i c h a l i d e s ( n o t l i s t e d ) . B y c o m p a r i s o n of the n - a l k y l m e r c u r i a l results alone, i t is possible to g e n e r a l i z e that b o t h h i g h e r o z o n a t i o n temperatures a n d the presence of a h a l o g e n l i g a n d o n m e r c u r y p r o m o t e carbon—carbon cleavage

during

the o z o n o l y s i s of the c a r b o n - m e r c u r y b o n d . A s a c h e c k of a possible r e a c t i o n p a t h w a y for the f o r m a t i o n of the shorter a c i d s d u r i n g o z o n a t i o n of n - a l k y l m e r c u r i a l s , p e n t a n o i c a c i d w a s o z o n i z e d for 4 hours at 10 ° C . T h e o z o n a t i o n w a s c a r r i e d out i n d i c h l o r o -


84


m e t h a n e w h i c h c o n t a i n e d s m a l l amounts of m e r c u r i c c h l o r i d e a n d m e r curous

chloride.

O n l y starting material could

be

detected

by

VPC

analysis of the p r o d u c t m i x t u r e . I n another test of the r e a c t i o n p a t h w a y for c a r b o n - c a r b o n

cleavage,

the exit gas f r o m the r e a c t i o n vessel d u r i n g a 10 ° C o z o n a t i o n of p r o p y l m e r c u r i c b r o m i d e w a s passed t h r o u g h a B a ( O H )

n-

solution. This

2

s o l u t i o n s h o w e d a n almost i m m e d i a t e a n d constant p r e c i p i t a t i o n of B a C 0

3

d u r i n g ozonation. H o w e v e r , further investigation revealed that methylene chloride yielded C 0

2

at a b o u t the same rate at 10 ° C .

Hence,

after


d e t e r m i n i n g that F r e o n 114 d i d n o t react w i t h o z o n e at —76°C., the test was r e p e a t e d o n d i - n - p r o p y l m e r c u r y at the r e d u c e d t e m p e r a t u r e a n d i n the i n e r t solvent.

U n d e r these c o n d i t i o n s C 0

w a s s t i l l p r o d u c e d at a n

2

a p p r e c i a b l e rate. O n e final e x p e r i m e n t , h o w e v e r , p l a c e d the o r i g i n of the C0

2

b a c k i n t o a n u n d e c i d e d l i g h t . F o r m i c a c i d w a s o x i d i z e d s l o w l y to

C0

2

w h e n o z o n i z e d i n F r e o n 114 at — 76 ° C . T o define p r o p e r l y t h e role w h i c h 0

The Role of Oxygen.

2

played

i n these ozonolysis reactions, n i t r o g e n was o c c a s i o n a l l y u s e d as the c a r r i e r gas for ozone.

A f t e r o z o n i z i n g n - h e x y l m e r c u r i c b r o m i d e at 1 0 ° C

the u s u a l 0 - 0

2

3

Experimental).

m i x t u r e , the r e a c t i o n w a s r e p e a t e d w i t h 0 - N 3

with

2

(see

B y c o m p a r i n g the r e a c t i o n p r o d u c t s f r o m runs 6 a n d 7

( T a b l e I ) , it c a n b e r e a d i l y seen t h a t n o p r o d u c t differences exist w h e n N

2

is s u b s t i t u t e d for 0 . 2

I n a s i g n i f i c a n t l y different a p p r o a c h to the p r o b l e m , i s o p r o p y l m e r curic chloride was oxygenated i n C H C 1 of 0

2

at 10 ° C for 2 hours at 24 liters

3

p e r h o u r . A n a l y s i s ( V P C ) s h o w e d t h a t 4 % of the o r g a n o m e r c u r i a l

h a d r e a c t e d to g i v e acetone. Stoichiometry of Ozone Uptake.. T h e results of the s t o i c h i o m e t r y s t u d y are o u t l i n e d i n T a b l e I. Intermediate Products from Ozonolysis

of Organomercurials.

b o n u s of the N M R m e t h o d for k i n e t i c analysis of the

A

0 -organomer3

c u r i a l r e a c t i o n was the fact t h a t c e r t a i n 0 - r e a c t i v e i n t e r m e d i a t e s w e r e 3

o b s e r v e d d u r i n g ozonolysis of some of the o r g a n o m e r c u r i a l s . Diisopropylmercury

yielded

isopropylmercuric

chloride

and

iso-

p r o p y l a l c o h o l as w e l l as acetone. T h e first t w o p r o d u c t s gave acetone upon

further reaction w i t h

0 .

The

3

following

equation

appears

to

d e s c r i b e this s y s t e m :

0

[(CH ) CH] Hg—— 3

2

2

CHCl-

—•

(CH ) CO
(CH ) CH—OH 8

2

(CH ) CHOH 3

2


(13)

7.

WATERS E T A L .

Ozonolysis

of

85

Organomercurials

T h e b e l i e f that acetone w a s one of t h e i n i t i a l p r o d u c t s of t h e r e a c t i o n is s u p p o r t e d b y its e x t r e m e l y fast rate of f o r m a t i o n c o m p a r e d w i t h t h e rate of o x i d a t i o n of i s o p r o p y l a l c o h o l to acetone b y 0 - 0 . 3

2

A s t u d y of t h e i n t e r m e d i a t e p r o d u c t s f r o m t h e ozonolysis of i s o p r o p l y m e r c u r i c c h l o r i d e shows alcohol adequately

accounts

that t h e r a t e of b u i l d - u p of i s o p r o p y l

f o r t h e rate of acetone f o r m a t i o n .

The

r e a c t i o n sequence therefore appears to b e o n e of c a r b o n - m e r c u r y c l e a v age, f o l l o w e d b y o x i d a t i o n b y ozone. T h e tertiary alkylmercuric halide, ierf-butylmercuric chloride y i e l d e d Downloaded by UNIV OF MINNESOTA on August 28, 2013 | http://pubs.acs.org Publication Date: June 1, 1972 | doi: 10.1021/ba-1972-0112.ch007

o n l y tert-butyl

a l c o h o l as t h e p r i m a r y p r o d u c t .

It was not until a l l the

o r g a n o m e r c u r i a l h a d r e a c t e d that acetone a p p e a r e d as a r e a c t i o n p r o d u c t (see R e a c t i o n 17, T a b l e I ) . T h u s i t a g a i n is suggested that a n a l c o h o l is the i m m e d i a t e p r o d u c t of C - H g cleavage b y ozone, at least i n t h e case of a l k y l m e r c u r i c h a l i d e s . Results Kinetic Studies. T h e o z o n a t i o n rates of 10 a l k y l m e r c u r i c h a l i d e s w e r e d e t e r m i n e d i n c h l o r o f o r m at 0 ° C . T h e rate of o z o n e o x i d a t i o n of i s o p r o p y l a l c o h o l to acetone u n d e r i d e n t i c a l c o n d i t i o n s w a s also m e a s u r e d . A n a t t e m p t to measure t h e o z o n a t i o n rate of six d i a l k y l m e r c u r i a l s f a i l e d , h o w e v e r , because t h e r e a c t i o n w i t h R H g w a s m u c h too fast u n d e r these 2

conditions. T h e p r e v i o u s l y d e s c r i b e d m e t h o d u s e d to o b t a i n rate constants f o r these reactions i n v o l v e d the c o n t i n u o u s passage of a s t r e a m of 0 — 0 3

2

t h r o u g h t h e r e a c t i o n vessel. F o r t h e k i n e t i c s t u d y of t h e s l o w e r - r e a c t i n g alkylmercuric halides the 0

3

concentration remained saturated a n d there-

fore constant. T h i s w a s n o t true f o r t h e d i a l k y l m e r c u r i a l s , h o w e v e r , since t h e y r e a c t e d so fast w i t h ozone that a n 0

3

concentration approaching the

s a t u r a t i o n v a l u e c o u l d never b e r e a c h e d .

T h i s s i t u a t i o n w a s also b o r n e

o u t b y t h e consistent o b s e r v a t i o n t h a t t h e K I t r a p ( of t h e r e a c t i o n a p p a r a t u s ) b e c a m e c o l o r e d d u r i n g t h e d i a l k y l m e r c u r y ozonations o n l y after a l l of t h e m e r c u r i a l h a d r e a c t e d .

B y c o m p a r i s o n , t h e reactions of t h e

a l k y l m e r c u r i c h a l i d e s w e r e s l o w e n o u g h so t h a t i o d i n e w a s f o r m e d i n the K I t r a p s h o r t l y after s t a r t i n g t h e 0 - 0 3

flow.

2

I n t h e case of t h e a l k y l m e r c u r i c h a l i d e s , t h e rate e q u a t i o n appears as,

~

d [ R

(ti

g X ]

=

k

[

R

H

g

X

]

[

°

3 ]

(

1

4

)

S i n c e w e m a y c o n s i d e r / c [ 0 ] to b e constant after i n i t i a l s a t u r a t i o n is 3

a c h i e v e d , t h e i n t e g r a t e d rate expression is that i n E q u a t i o n 15.


OZONE REACTIONS

COMPOUNDS

Table I.

Products

Reaction Temperature,

Organomercurial 1. C H C H C H H g B r

10

2. C H C H C H H g B r

0

3. ( C H C H C H ) H g

10

4. ( C H C H C H ) H g

0

5. ( C H C H C H ) H g

-76

3

2

3

2

2

2

3


W I T H ORGANIC

2

3

2

2

3

2

2

2

2

2

2

6. C H ( C H ) H g B r

10

7. C H ( C H ) H g B r

10

8. [ C H ( C H ) ] H g

10

9. [ C H ( C H ) ] H g

0

10. [ C H ( C H ) ] H g

-76

3

2

3

5

2

3

5

2

3

2

3

2

5

5

6

2

2

2

11. ( C H ) C C H H g C l

10

12.

10

3

13.

3

2

(CH ) CH(CH ) HgBr 3

2

2

(CH ) CHHgCl 3

2

2

10


°C

7.

Ozonolysis

WATERS E T A L .

of

Organomercurials

of Ozonolysis"

Inorganic

Organic

Products

Products

44% C H C H C O O H 54% C H C O O H 3

2

3

48% C H C H C O O H 50% C H C O O H 3

2

3

45% HgCl 35% Hg Cl 20% HgO

64% C H C H C O O H 20% CH COOH 15% H C O O H 3

2


2

2

3

2

67% C H C H C O O H 19% C H C O O H 14% H C O O H 3

2

3

72% C H C H C O O H 16% C H C O O H 12% H C O O H 3

2

3

30% CH 40% CH 10% C H 5% C H

3 3 3 3

30% CH 40% CH 10% CH 5% C H 50% CH 25% CH 10% C H 10% C H 5% C H 70% CH 10% C H 5% CH

R H g B r , etc.)

( 2 ) m a y b e e x p l a i n e d b y a s s u m i n g that a less


94


energetic t r a n s i t i o n state exists w h e n the d e v e l o p i n g p o s i t i v e c h a r g e o n m e r c u r y is m o r e f u l l y d i s p e r s e d .

H e n c e , b a s e d o n i n d u c t i v e a n d reso

n a n c e effects, one w o u l d expect the t r a n s i t i o n state for C - H g R or C - H g l c l e a v a g e to b e at a l o w e r e n e r g y l e v e l t h a n t h a t for C - H g C l

cleavage.

T h e a b o v e d i s c u s s i o n assumes the u s u a l i n d u c t i v e effect w h i c h h a l o gens h a v e o n c a r b o n i u m ions, b u t , of course, necessitates a r e v e r s a l of the u s u a l o r d e r for resonance effects. fluorine

I t is i m p o r t a n t to note t h a t w h i l e

c a n q u i t e effectively f o r m a p i b o n d w i t h c a r b o n , i t c a n n o t do so

w i t h the l a r g e m e r c u r y a t o m . T h u s , structures s u c h as 24 s h o u l d be i m Downloaded by UNIV OF MINNESOTA on August 28, 2013 | http://pubs.acs.org Publication Date: June 1, 1972 | doi: 10.1021/ba-1972-0112.ch007

p o r t a n t o n l y f o r the l a r g e r halogens.

+ - ^ C -

Hg-_^J=X

(24)

I n this same r e g a r d , the t r a n s i t i o n state for cleavage of the d i a l k y l m e r curials m u s t b e of r e l a t i v e l y l o w e r energy, solely as a result of the i n d u c t i v e effect of the a l k y l g r o u p since h y p e r c o n j u g a t i o n effects s h o u l d b e nonexistent here. F i n a l l y , i n this s t u d y , as w e l l as most others

( 2 ) , s u b s t i t u t i o n of

c a r b o n for h a l o g e n as t h e m e r c u r y l i g a n d p r o d u c e d a h u g e rate increase f o r e l e c t r o p h i l i c cleavage.

A l t h o u g h the P a u l i n g e l e c t r o n e g a t i v i t y values

for i o d i n e a n d c a r b o n are i d e n t i c a l , the b o n d s of these t w o atoms to m e r c u r y are t o t a l l y d i s s i m i l a r . H e n c e , comparisons of these t w o systems s h o u l d i n v o l v e a c o m p l e t e t r e a t m e n t of o r b i t a l t h e o r y before o n e arrives at a n y conclusions c o n c e r n i n g r e l a t i v e r e a c t i v i t i e s . T u r n i n g to the other h a l f of the k i n e t i c s t u d y — t h a t of r a t e effects f r o m changes of the R g r o u p i n R H g X — i n c r e a s e d s u b s t i t u t i o n o n the c a r b o n b o u n d to m e r c u r y c a u s e d a n a p p r e c i a b l e r e a c t i o n rate increase ( T a b l e I I I a n d sequence 17).

T h e s e results c e r t a i n l y i n d i c a t e t h e g e n

e r a t i o n of p a r t i a l p o s i t i v e c h a r g e o n c a r b o n i n the t r a n s i t i o n state of the carbon-mercury cleavage reaction. W h i l e such a positive charge b u i l d - u p m i g h t a p p e a r i m p o s s i b l e at first c o n s i d e r a t i o n of the f o u r g e n e r a l m e c h a nisms for e l e c t r o p h i l i c cleavage

( R e a c t i o n s 3 - 6 ) , m i n o r m o d i f i c a t i o n of

t w o of t h e m a d e q u a t e l y p r e d i c t s i t . Jensen a n d R i c k b o r n ( 2 ) d i s c u s s e d the p o s s i b i l i t y of t r a n s i t i o n states i n w h i c h the e l e c t r o p h i l i c species w a s p a r t i a l l y b o u n d to the σ o r b i t a l of carbon—mercury

bonds.

T h u s the f o u r t h " c e n t e r " of

the

four-center

b r o m i n a t i o n m e c h a n i s m w a s p i c t u r e d as t h e carbon—mercury b o n d itself, o r m o r e specifically, the c a r b o n sp

s

orbital (2).


7.

WATERS E T A L .

Ozonolysis

of

95

Organomercurials

+ δ /

Br

+

Hg

Br^ ^Br " Downloaded by UNIV OF MINNESOTA on August 28, 2013 | http://pubs.acs.org Publication Date: June 1, 1972 | doi: 10.1021/ba-1972-0112.ch007

8

(25)

T h e c a r b o n sp

a t o m i c o r b i t a l w a s d e p i c t e d as a s o l i d l i n e " i n d i c a t i n g

3

that its c h a r g e d e n s i t y is c h a n g e d p r i m a r i l y b y e l e c t r o n i c factors r a t h e r t h a n the a c t u a l m a k i n g a n d b r e a k i n g of the b o n d " (2).

I n a similar

f a s h i o n the same authors i l l u s t r a t e d the S 2 cleavage of a d i a l k y l m e r E

curial by X H g . +

7°^

8 •Hg—R +

(26)

Hg

8

+

\

X

T h e authors stated t h a t the p o s i t i v e c h a r g e w o u l d p r o b a b l y b e d i v i d e d b e t w e e n the three a t o m i c centers a n d t h a t e l e c t r o n - d o n a t i n g groups o n c a r b o n s h o u l d increase t h e cleavage rate. Mechanism. I n c o n s i d e r a t i o n of a possible m e c h a n i s m for

cleavage

of t h e c a r b o n - m e r c u r y b o n d b y o z o n e , i t s h o u l d b e possible to r u l e o u t the S 1 m e c h a n i s m ( R e a c t i o n 3 ) E

demands

altogether.

This mechanism clearly

t h e f o r m a t i o n of a c a r b a n i o n i n the r a t e - d e t e r m i n i n g step.

L i k e w i s e , the S i m e c h a n i s m for e l e c t r o p h i l i c cleavage seems i m p r o b a b l e E


96


since the b i m o l e c u l a r r a t e - d e t e r m i n i n g step i n v o l v e s a s i m i l a r n e g a t i v e c h a r g e b u i l d - u p o n c a r b o n (4).

T h e t r a n s i t i o n state to s u c h i n t e r m e d i a t e s

w o u l d o b v i o u s l y p r o d u c e i n v e r t e d r e l a t i v e - r a t e orders f r o m t h a t s h o w n i n s e q u e n c e 17. O f the t w o r e m a i n i n g m e c h a n i s m s , the four-center a n d S 2 processes, E

no selection is possible b a s e d o n the d a t a c o l l e c t e d i n this s t u d y .

More

over, since t h e S 2 a n d S i m e c h a n i s m s are m e r e l y t h e t w o possible ex E

E

t r e m e versions of the four-center m e c h a n i s m , t h e exact " p u r i t y " of a n S 2 or f o u r - c e n t e r process c a n often not b e d e t e r m i n e d . O n e test w h i c h E


has b e e n u s e d to d e t e r m i n e the p a r t i c u l a r i n v o l v e m e n t of t h e n u c l e o p h i l i c p a r t of the a t t a c k i n g X - Y m o l e c u l e d u r i n g o r g a n o m e r c u r i a l c l e a v age reactions is to change the n a t u r e of Y s u c h t h a t it b e c o m e s a better or p o o r e r n u c l e o p h i l e ( 2 1 ) .

I f the r e a c t i o n rate r e m a i n s u n c h a n g e d , the

process is p u r e l y S 2—i.e., no i n t e r a c t i o n occurs b e t w e e n the Y

group

and mercury.

course

E

T h i s p r o c e d u r e of m e c h a n i s t i c d e t e r m i n a t i o n is of

i m p o s s i b l e f o r cleavage reagents s u c h as ozone. A t this p o i n t i n o u r studies w e f a v o r a

five-membered

cyclic transi

t i o n state, q u i t e analogous to the four-center t r a n s i t i o n state

(Reaction

5 ) , except t h a t n o σ b o n d s of the a t t a c k i n g e l e c t r o p h i l e are b r o k e n . f o u r t h b o n d i n g " c e n t e r " is the c a r b o n sp

B

The

o r b i t a l as i n structures 25

a n d 26.

\

—

8

+

c

8 -Hg-Cl +

/

(27)

I I

A l t h o u g h no

kinetic evidence

exists at this t i m e to i n c l u d e

n u c l e o p h i l i c o x y g e n i n s u c h a b o n d i n g process (i.e., S 2 vs. E

the

four-center),

i t is difficult to b e l i e v e that a n e g a t i v e l y c h a r g e d o x y g e n w o u l d n o t p a r t i c i p a t e i n the n e a r b y f o r m a t i o n of a p o s i t i v e l y c h a r g e d m e r c u r y a t o m . Such a

five-membered

c y c l i c t r a n s i t i o n state has b e e n p r o p o s e d f o r the

t r i i o d i d e cleavage of c a r b o n - m e r c u r y b o n d s ( 2 ) .

W h i l e s u c h a structure

is u n l i k e l y for the l i n e a r I ~ i o n , i t s h o u l d easily a c c o m m o d a t e the o z o n e 3

m o l e c u l e w h o s e b o n d i n g a n g l e is 116° p l a u s i b i l i t y of S t r u c t u r e 27 d e p e n d s

(12).

O f course the g e o m e t r i c a l

o n t h e degree of

carbon-mercury


7.

WATERS E T A L .

Ozonolysis

of

b o n d b r e a k i n g i n the t r a n s i t i o n state.

97

Organomercurials

M o d e l s s h o w that the e x t r e m e l y

l o n g c a r b o n - m e r c u r y b o n d ( 2 . 0 6 - 2 . 2 0 A ) (22)

n e e d not b e stretched too

m u c h i n o r d e r to p e r m i t a 1,3-dipolar attack b y o z o n e as p i c t u r e d . T h e exact c h r o n o l o g y of b o n d b r e a k i n g a n d b o n d m a k i n g is i m p o r tant i n c o n s i d e r i n g S t r u c t u r e 27 as the t r a n s i t i o n state f o r carbon—mercury cleavage.

T h e i n i t i a l attack b y o z o n e m u s t l i e o n the S 2 side of the E

c o n c e r t e d , four-center process i n o r d e r to a l l o w for the b u i l d - u p of some positive charge on carbon.

T h u s , the e l e c t r o p h i l i c o x y g e n s h o u l d h a v e

a c h i e v e d a greater degree of b o n d m a k i n g w i t h the c a r b o n sp

orbital

3


t h a n t h a t of the n u c l e o p h i l i c o x y g e n w i t h t h e m e r c u r y a t o m b y the t i m e S t r u c t u r e 27 is r e a c h e d . A t t e n t i o n is p a i d to this b o n d m a k i n g order b y the different lengths of p a r t i a l b o n d s i n S t r u c t u r e 27

(2).

T h e o v e r a l l i m p o r t a n c e of t r a n s i t i o n state 27 is that rate sequences 16 a n d 17 are a d e q u a t e l y e x p l a i n e d . It is o n l y this t y p e of energy m a x i m u m w h i c h p r e d i c t s p a r t i a l p o s i t i v e charge o n b o t h c a r b o n and m e r c u r y . As

a n alternate t r a n s i t i o n state, one m i g h t e n v i s i o n the r e s u l t of

i n i t i a l attack b y the 1,2-dipolar resonance

f o r m of o z o n e via

a four-

m e m b e r e d c y c l i c t r a n s i t i o n state.

Since this t r a n s i t i o n state c o u l d y i e l d a n i n t e r m e d i a t e w h i c h i n t u r n c o u l d c o n c e i v a b l y p r o d u c e the p r o d u c t s o b s e r v e d , i t cannot b e r u l e d out at this p o i n t . P e r h a p s after m o r e d a t a h a v e b e e n c o l l e c t e d c o n c e r n i n g the existence

of the analogous

Staudinger intermediates

(23)

from

olefin

reactions, i t w i l l b e possible to choose b e t w e e n the t w o r e a c t i o n p a t h w a y s . F o l l o w i n g the p r o p o s e d

t r a n s i t i o n state 27, a l i k e l y i n t e r m e d i a t e

w o u l d b e a t r i o x i d e s i m i l a r to that p r o p o s e d h y d r o g e n cleavage

(Reaction

b y O u e l l e t t e for s i l i c o n -

12).


98


(29)

[—C—0—0—0—HgX]

/

A l t h o u g h this i n t e r m e d i a t e was n o t i s o l a t e d or e v e n d e t e c t e d b y N M R spectroscopy

( a t 31 ° C ) , its existence is i n f e r r e d f r o m the t y p e of o r g a n i c

a n d i n o r g a n i c p r o d u c t s f o r m e d i n the r e a c t i o n . F u t u r e l o w t e m p e r a t u r e N M R studies of the ozonolysis solutions w i l l b e d o n e to v e r i f y S t r u c t u r e 29.


The

trioxide

intermediate

may

decompose

by

many

pathways.

Results o b t a i n e d i n this p a p e r suggest that these d e c o m p o s i t i o n p a t h w a y s m i g h t e x p l a i n the t w o classes of m e r c u r y salts p r o d u c e d ( H g

2 +

and H g ) +

as w e l l as the t w o d i v i s i o n s of o r g a n i c p r o d u c t s f o r m e d ( w i t h a n d w i t h o u t carbon-carbon

scission).

T h i s p o s s i b i l i t y looks p a r t i c u l a r l y a t t r a c t i v e

w h e n the a c e t o n e / f o r m i c a c i d a n d H g C l / H g C l 2 ratios are c o m p a r e d i n 2

R e a c t i o n 13, T a b l e I.

2

H o w e v e r , b e f o r e e x t e n d i n g s p e c u l a t i o n o n this

matter, s e v e r a l f u t u r e experiments a n d t h e o r e t i c a l c a l c u l a t i o n s m u s t b e pursued.

A m o n g these w i l l b e a n effort to m e a s u r e q u a n t i t a t i v e l y t h e

a m o u n t a n d t y p e ( s i n g l e t or t r i p l e t ) of oxygen generated b y a n 0 / N 3

ozonolysis.

2

A l s o , t h e o r e t i c a l c o n s i d e r a t i o n w i l l b e g i v e n to the m e t a l o -

t r i o x y a l k a n e s i n l i g h t of p u b l i s h e d d a t a o n the k n o w n d i a l k y l t r i o x i d e systems (24,

25).

Synthetic U t i l i t y . O n e g o a l of this research w a s to investigate n e w s y n t h e t i c uses of o r g a n o m e r c u r i a l s . A l t h o u g h the s y n t h e t i c u t i l i t y of this r e a c t i o n has n o t b e e n

extensively i n v e s t i g a t e d , p r o d u c t s

s u c h as that

f r o m R e a c t i o n 16 i n T a b l e I d o suggest a possible u t i l i t y to

organic

chemists. T h u s , the p r e p a r a t i o n of α-alkoxyketones s h o u l d b e possible b y consecutive a l k o x y m e r c u r a t i o n a n d o z o n a t i o n reactions. OR' HgX

2

R2C = C H — R R'OH

R2C—CH—R HgX

OR

(30)

0; R 2—C—C—R Ο A n a t t e m p t to p r e p a r e α-diketones via consecutive

hydroxymercuration

a n d o z o n a t i o n f a i l e d , p r e s u m a b l y because of the p r o d u c t ' s extreme r e a c t i v i t y t o w a r d s ozone.


7.

WATERS E T A L .

Ozonolysis

of

Organomercurials

99

COOH Downloaded by UNIV OF MINNESOTA on August 28, 2013 | http://pubs.acs.org Publication Date: June 1, 1972 | doi: 10.1021/ba-1972-0112.ch007

COOH 90% A s t u d y is n o w u n d e r w a y to e v a l u a t e c o m p l e t e l y t h e f u t u r e synthetic r o l e o f t h e o x y m e r c u r a t i o n - o z o n o l y s i s sequence. Literature

Cited

1. Jensen, F. R., Rickborn, B., "Electrophilic Substitution of Organomercu rials," McGraw-Hill, New York, 1968. 2. Belew, J. S., "Oxidation," Vol. I, R. L. Augustine, Ed., p. 259, Marcel Dekkar, New York, 1969. 3. Aleksandrov, Yu. Α., Sheyanov, N. G., Shushunov, V. Α., Zh. Obshch. Khim. (1968) 38, 1352-6; CA (1968) 69, 77388q. 4. Aleksandrov, Yu. Α., Sheyanov, N. G., Zh. Obshch. Khim. (1966) 36, 953; CA (1966) 65, 8955e. 5. Emel'yanov, Β. V., Shemyakina, Ζ. N., Shvarov, V. N., Khim.Prom.(1968) 44, 498-500; CA (1968) 69, 7964y. 6. Aleksandrov, Yu. Α., Sheyanov, N. G., Zh. Obshch. Khim. (1969) 39, 141-3; CA (1969) 70, 96847a. 7. Spialter, L., Austin, J. D., Inorg. Chem. (1966) 5, 1975-8. 8. Ayrey, G., Barnard, D., Woodbridge, D. T.,J.Chem. Soc. (1962) 2089-99. 9. Bockemuller, W., Pfeuffer, L., Ann. (1939) 537, 178. 10. Ouellette, R. J., Marks, D. L.,J.Organometal. Chem. (1968) 11, 407-13. 11. Pike, P. E., Marsh, P. G., Erickson, R. E . , Waters, W. L . , Tetrahedron Letters (1970) 2679; Pike, P. E., MS Thesis, University of Montana (1970). 12. Rivera, J. T., MS Thesis, University of Montana (1971). 13. Marvel, C. S., Gauerke, C. G., Hill, E. L., J. Amer. Chem. Soc. (1925) 47, 3009-11. 14. Gilman, H., Brown, R. E., J. Amer. Chem. Soc. (1929) 51, 928. 15. Hatton, J. V., Schneider, W. G., Siebrand, W.,J.Chem. Phys. (1963) 39, 1330-6. 16. Kiefer, E. F., Waters, W. L., J. Amer. Chem. Soc. (1965) 87, 4401. 17. Bailey, P. S., Reader, A. M., Chem. Ind. (London) (1961) 1063. 18. Ref. 2, p. 98. 19. Brilkina, T. G., Shushunov, V. Α., "Reactions of Organometallic Compounds with Oxygen and Peroxides," Chemical Rubber Co. Press, Cleveland, 1966. 20. Hughes, E. D., Ingold, C. K., Roberts, R. M. G., J. Chem. Soc. (1964) 3900.


100

OZONE REACTIONS W I T H

ORGANIC

COMPOUNDS

21. Charmen, Η. Β., Hughes, E. D., Ingold, C. K., J. Chem. Soc. (1959) 2530. 22. Grdenic, D., Quart. Rev. (1965) 19, 303-28. 23. Story, P. R., Alford, J. Α., Ray, W.C.,Burgess, J. R., "Abstracts of Papers," 161st National Meeting, ACS, March 1971, PETR A13. 24. Bartlett, P. D., Günther, P.,J.Amer. Chem. Soc. (1966) 88, 3288. 25. Bensen, S. W., J. Amer. Chem. Soc. (1964) 86, 3922.


RECEIVED June 21, 1971. Supported by the National Science Foundation Grant No. GP-18317.


The Ozonolysis of Organomercurials - Advances in Chemistry (ACS

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