Synthesis of α,ω-dicarboxylic acids and unsaturated carboxylic acids from silyl enol ethers

0040-4039/83 $3.00 + .oo 01983 Pergamon Press Ltd.

Tetrahedron Letters,Vol.24,No.41,pp 4439-4442,1983 Printed in Great Britain

SYNTHESISOF a,w-DICARBOXYLIC ACIDS AND UNSATURATED

CARBOXYLIC

ACIDS

FROM SILYL ENOL ETHERS

Isao Saito:Ryu Nagata,Kazuaki Yuba,and Teruo Matsuura Department

of Synthetic

Chemistry,

Faculty

of Engineering,

Kyoto University,

Kyoto 606, Japan

Swmary :

The synthesis

carboxylic

acids

by metal-ion

dimethylsilyloxy

Metal-ion

method

ring-opening

useful reaction

usually employs peroxide

unstable

1-hydroxycycloalkyl

relatively applied method

reactive

cyclic

to larger-membered for the synthesis

cyclic enones, addition

hydroperoxides,

ketones cyclic

obtained

undesirable

In addition,

converting

silyl enol ethers

originally

present

3

this method

tl = 0, I, 2, 3

4439

and a separation

is only effective

We previously

enol ethers

for

and cannot be reported

from a wide range of ketones,

We now wish to report a general,

below.

ketones with

to isolate

formation

and cyclohexanone

ketones or cyclic enones.

followed

efficient

an effective including

by acid-catalyzed method

for

acids having double the number of carbon atoms

in the ketones and to monocarboxylic

groups by a route outlined

of cyclic

of the incapability by-product

such as cyclopentanone

to a,w-dicarboxylic

Since the traditional

from the reaction

them to t-butyldimethylsilyl

peroxide.

mono-

has long been known as a

in the early 1950s.'

of cy-silyloxy hydroperoxides

by converting

with hydrogen

hydroperoxides

of strong acids because

ketones are inevitable. 192

and unsaturated

ring-opening of cyclic a-t-butyZ-

of cycloalkyl

of peroxides

in the presence

acids

has been described.

since its discovery

mixture

hydrogen

from staring

promoted

hydroperoxides

promoted

synthetically

of a,w-dicarboxylic

acids possessing

terminal

methylene

4440

t-Butyldimethylsilyl ketones

(TBDMS) enol ethers are readily

(LDA/~BDMsC~/I-~F-HMPA).

prepared

in good yields

peroxide

in the presence

previously.' methanol

Addition

of a catalytic

of a-silyloxy

gave after usual workup Notably,

the

reaction

a-t-Butyldimethylsilyloxy

by the reaction

at 0 "C under nitrogen

amount

and successive

1,12-dodecanedioic

of a-silyloxy

HY DROPEROXI

(54%).

hydroperoxide?

of FeS04

from 0-silylated

YIELD

Ii

TBDMSO

H02C(CH2)&02H

53

OOH

3

68

3

4

H02C(CH2),4C02H

4

nitrogen. b Isolated

After

(%jb

54

2

reaction

silyl esters

are shown in Table

PRODUCT

2

aThe

(1.2 equiv mol) in

of the resulting

Other examples

obtained

(TFA) as described

1 TBDMS

2, $1 were

la

DE

1

acid

a solution

acid hydrolysis

acid

(is:,

silyl enol ethers with hydrogen

of trifluoroacetic

hydroperoxide_Lto

from the corresponding

hydroperoxides

of the corresponding

TABLE

ENTRY

available

was conducted the reaction

in methanol

the mixture

using

was treated

FeS04 with

(1.2

72

equiv

1 N H2S04

mol) at 0 ‘C under at room temperature.

yield.

5

5 (76%)

7 (87%)

I.

4441

1,3-cyclohexadien-2-01 regiospecific

>-produced

fashion,

with no iscmeric olefins

It has been well recognized induced

decomposition

the formation

(22, lOZ)-2,10-dodecadien-1,12-dioic

of products

moderate

in methanol

yield.

Table

of zand

intermediates

intercepted

and elimination.5

to a solution

at 0 "C under nitrogen,

by cupric

hydroperoxide

monocarboxylic

by metal-ion

salts to result

When a methanolic

of a-silyloxy

unsaturated

produced

solution

acid from C$3 whereas E

the Cu(OAc)2-FeS04

in

of FeS04

and CU(OAC)~

(3.6

acid was obtained

II details the results.6 We already observed a stereospecific

of (2Z)-2,5-hexadienoic a 1:l mixture

is oxidatively

of substitution

(1.2 equiv mol) was added dropwise equiv mol)

being detected.

that the carbon radical

of hydroperoxides

acid4 (7_, 87%) in a

in

formation

promoted fragmentation of$gave

in 77% yield.

TABLE HY DROPEROXI

ENTRY

Ila PRODUCT

DE

(8

b

WO2”

2

1

YIELD

NCOZH

-02”

4

73

H

TBDMSO

77

8 aThe CU(OAC)~ H2S0,,,

vvvCo2H

reaction was conducted (3.6

equiv

in methanol

mol) at 0 ‘W under

using

nitrogen.

10

FeS04

(1.2 equiv

After treatment

mol) and with I N

the mixture was extracted with ether and purified by silicagel column b isolated yield after column chromatography.

chromatography.

The simple substrates peroxides

chosen

in the synthesis

availability

of a-silyloxy

of dicarboxylic

of reasonably

in usual organic

solvents

in this study may illustrate

acids and unsaturated

stable a-silyloxy suggests

hydroperoxides

hydroperoxides

a more significant

in organic

the utility

synthesis. 7

of a-silyloxy

carboxylic

combined

acids.

hydro-

The easy

with their high solubility

role for the metal-ion

promoted

reactions

4442

REFERENCES (1)

For a review,

see (a) G. Sosnovsky

Wiley-Interscience,

AND NOTES

and 0. J. Rawlinson

New York, 1971, Vol.

"Organic

Peroxides",

D. Swern, ed.,

II. Chapter II. (b) F. Minisci, Synthesis,

1

(1973). (2)

For example,

(3)

I. Saito, R. Nagata,

see E. G. E. Hawkins,

(4)

Mp 120-122

'C; 'H NMR (CD~COCD~)

J = 12.5 Hz), 6.30 (5)

(a) J. K. Kochi, Vol. 2, Chapter

(dt,

6 1.00-1.90

3463.

Tetrahedron p----

Lett.,,2$, 1737 (1983).

(m, 8 H), 2.40-2.90

(m, 4 H), 5.70 (d, 2 H,

2 H, J = 12.5, 6 Hz), 9.50 (br s, 2 H).

"Free Radicals", 23.

J. Chem. Sot., lz5,

K. Yuba and T. Matsuura,

Wiley-Interscience,

New York, 1973, Vol. 1, Chapter

(b) B. Acott and A. L. J. Beckwith,

(c) For a recent synthetic

application,

Aust. J. Chem., 2,

see S. L. Schreiber,

11,

1342 (1964).

J. Am. Chem. Sot., 12,

6163

(1980). (6)

The following 7.2 mnol) syringe

procedure

in methanol

under stirring.

was added dropwise nitrogen, extracts

is representative.

A solution

of FeS04.7H20

to this solution.

then treated

mixture

This work was supported of Education

acid

(Received in Japan 30 June 1983)

(10 mL)

for 30 min under

with ether.

The

The residue was chromatographed

(207 mg, 73%).

in part by a Grant-in-Aid

of Japan.

(1.30 g,

mg, 2 mmol) by

in methanol

was stirred

(10 mL) for 1 h and extracted

to give 7-octenoic

of CU(OAC)~

$,(548

(667 mg, 2.4 mmol)

The resulting

with 1 N H2S04

solution

hydroperoxide

were dried over anhydrous Na2S04 and evaporated.

on a silica gel column (7)

To an ice-cooled

(40 mL) was added a-silyloxy

for Scientific

Research

from the Ministry