Carbonylation of alkyl sulfonates catalyzed by cobalt complexes

. *

oo40-4039/91 $3.00 + .oo Pergamon Press plc

Temhedmn Letters. Vo1.32, No.26. pi 3091-3094.1991 Priited in Great Britain

CARBONYLATION OF ALKYL SULFONATFS CATALYZED BY COBALT COMPLEXES Hisao URATA, Daisuke GCYIO, and Takamasa FUCHIKAMI* Sagami Chemical Research Center 4-4-1, Nishi-Ohnuma, Sagamihara, Kanagawa 229, Japan Summary: Alkyl sulfonates (Rl-OS02R2J react with carbon monoxide and alcohol (R3-OH) in the presence of catalytic amounts of Co complex and NaZ to afford the corresponding esters (RICOORS) in moderate to good yields.

We have developed transition-metal

a variety of catalytic carbonylations

complexes until now.

of organic halides’

by using

Among them, it is very interesting reaction conditions

that carbonylation of organic halides (Heck type carbonylationz) does proceed in good yields without the addition of base when the reactions are carried out in tetraalkyl-substituted solutionsle

such as tetramethylurea.

pseudo-halides, solutions.

urea

We have been pursuing a new catalytic carbonylation of

which can be easily prepared from alcohols, in tetraalkyl-substituted

urea

Reported herein are our preliminary results on the novel synthesis of carboxylic acid

esters via cobalt or palladium complexes catalyzed carbonylation of alkyl sulfonates (Rl-OSG2R2) with alcohol (R3-OH) under carbon monoxide pressure in the presence of a catalytic amount of sodium iodide in tetramethylurea (TMU) solution (Scheme I). Scheme I R1-OS0,R2

+

CO

+

Co or I’d cat.

R3-OH

TMU, NaI 100°C, 24 h Rr = primary and secondary alkyl groups.

=

R*-COOR3

R2 = Me, Bn, and pTo1. R3 = Me, Et, etc. We first studied catalytic carbonylation of n-octyl-acetate (n-CsHl+Ac), CsHr7-~GCF3),

-trifluoroacetate (n-

-ethyl carbonate (n-CsHl7-GCGDEt), and -methanesulfonate (n-CsI-Ir~2CHs)

with ethanol (Rs=Et) in the presence of catalytic amounts (10 mol%) of Cs(CO)s

under 50 atm of

CO pressure at 1OO’Cfor 24 h in TMU. Only n-octyl methanesulfonate was found to successfully undergo the carbonylation,3 and ethyl nonanoate (2) could be obtained in 35% yield with 15% of ethyl octyl ether (3) as a by-product. 4 To our knowledge, this is the first example of transitionmetal complexes catalyzed carbonylation of nlkyl sulfonates. Seeking for the optimum reaction conditions of this carbonylation, we selected n-octyl methanesulfonate (1, R1=n-CsHr7, Rz=Me) as a starting material and examined catalytic carbonylation of 1 with ethanol under various reaction conditions (eq. 1). dramatically reaction

Results are summarized

increased

mixture

benzylsulfonate

in Table I.

The yields of 2 (60%-72%)

when sodium iodide5 (NaI, 10 mol%-100

as shown

in Entries

2-4.

(Rz=Bn) and p-toluenesulfonate

were

mol%) was added to the

Not only methanesulfonate ester but also fR2=p-Tol) esters can be carbonylated in the

3091

3092

n-CsH,,rOS0$?2 1

co cat.

+ CO + EtOH -

rrC&H,,-COOEt 2

Sob. lOO”C, 24 h

Table I. Carbonylation

+ rG,,H,TOEt 3

(1)

(1)Catalyzed by Cobalt Complexesa

of n-Octyl Sulfonates

Entry

R2

Cat.

NaI(mol%)

Solv.

2(%)

3(%)

0

Me

CO2(c0)8

0

TMU

35

15 2

2

Me

@2@338

10

TMU

60

3

Me

cO2(co)8

50

TMU

72

1

4

Me

cO2(co)8

100

TMU

72

4

5

Bn

Co2fCO)I3

100

TMU

80

0

6

p-To1

cOdc0)8

100

TMU

74

2

7c

PQaC6H4

cO2(co)S

100

TMU

37

13

8

Me

cO2(c0)&?

100

DMPU

63

2

9

Me

CQ(C0)8

100

NMP

72

2

10

Me

CoBrz

50

TMU

56

9

11

Me

co12

0

TMU

57

6

12

Me

Co(acac)$

50

TMU

53

10

sulfonate

(1 mmol),

u. All reactions ethanol

were carried out in an autoclave

(20 ml) containing

(10 mmol), catalyst (10 mol%), NaI, and solvent

100°C for 24 h. obtained

b.

Starting

in 23% yield.

material

was recovered

n-octyl

(1.4 ml) under 50 aim of CO pressure in 15% yield.

c.

I-Iodooctane

d. acac = 24pentanedionato.

presence of NaI to form 2 in good yields (Entries 5 and 6) under the same reactlon conditions. the other hand, n-octyl p-nitrobenzenesulfonate into 2 in insufficient

yield.

equimolar

amount

Although

TMU would

transition

of NaI under

similar

be the most

did not take place reaction

suitable

(DMPU)

(Entries 8 and 9) as solvents. metal complexes

(R2=p-02NC6H4,

Carbonylation

tetrahydro-2(1Zf)-pyrimidinone employable

at

was also

investigated

conditions

solvent

and

On

Entry 7) could be converted even

in the presence

on employing

for this reaction,

N-methylpyrrolidone

other

of an

substrates.6

1,3-dimethyl-3,4,5,6(NMP)

could

be also

Cobalt catalysts gave the best results among group VIII as a catalyst.

It is noteworthy

that cobalt salts, such as

CoBr2, CoI2, and Co(acac)n (n=2 and 3), have potent catalytic activity similar to Co2(CO)s for this carbonylation the addition From atoms, assumed formed

(Entries 10-12).

When Co12 was used as a catalyst, it does not necessarily

require

of NaI to progress the reaction and 2 was formed in 57% yield. the notion

the present

that sulfonyloxy

carbonylation

that the reaction according

equiv.) n-octyl methanesulfonate solution (eq. 2).

rd8HITOS02Me

1

should

might proceed

to progress

groups

are thought

to be pseudo-halogen

be one of Heck type carbonylation. in the presence

the catalytic

cycle.

was carbonylated

+ CO + EtOH

(-OS02R2)

Therefore,

of base to trap sulfonic

In fact, in the presence

we

acid (R2S03H)

of triethylamine

(1

to give 2 in 52% yield with 3 (2%) in ethanol

COAX (10 mol%) Nal (50 mol%) c2+3 EtsN (1 eq.)

100°C, 24 h

52%

(2)

2%

3093

Table II. Carbonylathi

Entry

Catalyzed by Transition

of Alkyl Sulfonates

substrate

-0Ms

1

Metal Complexes* Yield(%jb

ProdUCt

79

4

2=

75

-COOEt

3

pb&G=t

61

EtO~COOEt

56

PbPOMa

4 5

73

6

76

7d

mO~OMS

78

EtOCo-COOEt

OH 0

ge

OMS

+

OMS 11 Old

c)-

+ 96

o-

109

COOEt

a. All reactions

were carried

C@(CO)s

COOEt 36

added

COOEt

out in an autoclave

containing

substrate

(10 mol%), NaI (50 mol%), and TMU (1.4 ml) under

1OO’C for 24 h unless otherwise solution.

34

12 COOEt

mmol),

43f

d. The reaction to the reaction

noted.

b. Isolated yield.

was done in the presence

mixture.

(1 mmol),

ethanol

CO pressure

(10

(50 atm) at

c. The reaction was run in NMP (1.4 ml)

of 20 mmol of ethanol.

f. Yield was determined

by means of GLC.

e Ethanol

was not

g. (Ph3PI2PdC12 (5

mol%) was used as a catalyst instead of Co#O)s. As shown the presence

of catalytic

mixed solvent reaction

(1) are effectively

above, n-octyl sulfonates amounts

of NaI under

to afford the ethyl nonanoate

conditions

(Co2(CO)a

primary- and secondary-alkyl 48-79%

l-8)

Treatment

of 3-hydroxybutyl

in TMU gave T-valerolactone from alkyl sulfonates

cobalt carbonyl carbonylated methanesulfonate

complex to afford

in good yields. was

examined

in TMU-EtOH

Under the optimum

methanesulfonate

in moderate

yield.

For example, to the

to the desired (10, Entry

Carboxylic

dodecyl

methanesulfonate

On the contrary, optimum carbonylation

esters

in

8) with carbon

acids could

of EtOH in TMU solution

acid in 88% yield.

exposed

of a variety of

and results are cited in Table II.

were converted

by using Hz0 instead

tridecanoic

(11)

monoxide

to good yields.

(4-12) were investigated,

(Entries

synthesized

carbon

by using Co catalyst in

cat.; 10 mol%, NaI cat.; 50 mol%), carbonylation

sulfonates

sulfonates

yields.

pressurized

(2) in moderate

All primary-alkyl monoxide

carbonylated

be also

catalyzed

by

(4) was nicely

when cyclohexyl conditions, ethyl

3094

cyclohexanecarboxylate We found

was scarcely obtained

that palladium-phosphine

when secondary-alkyl

sulfonates

and cyclohexene

complex

were employed

active (R)-(-)-12 and (S)-(+)-12 was also attempted

and diethyl

2-methylsuccinate

the products

were optically

of carboxylic

complex

in similar

under the same reaction conditions

yields in both cases, however,

neither

of

active.7

outlined

above provides

a new, simple, and efficient approach

acids and their esters starting

from the corresponding References

was obtained

as a main product.

than cobalt carbonyl

as listed in Entries 9 and 10. The carbonylation

of optically

The method

was detected

gave better results

from alkyl sulfonates

to the synthesis

which can be easily prepared

alcohols in one step in high yields.

and Notes

(1) (a) Urata, H.; Kosukegawa,

0.; Ishii, Y.; Yugari, H.; Fuchikami,

4403. (b) Urata, H.; Ishii, Y.; Fuchikami, Takahashi,

S.; Fuchikami,

Fuchikami,

T. submitted

T. ibid., 1989,30,

T. I. Org. Chem., in press. to Tetrahedron

T. Tetrahedron

Left., 1989,30,

4407. (c) Urata, H.; Maekawa,

H.;

(d) Urata, H.; Hu, N. -X.; Maekawa,

H.;

Lett.

(2) Heck, R. F. Palladiiun Reagents in Organic Syntheses; Academic Press: New York, 1985. did not show any reactivity toward the (3) n-Octyl acetate and n-octyl ethyl carbonate carbonylation, and the starting materials were recovered in 75% and 99% yields, respectively. In the case of n-octyl trifluoroacetate, (4) Similarly, converted reaction

n-octyl

I-octanol

benzylsulfonate

carbonylation

When

conditions,

in 61% yield.

(R2=Bn) and p-toluenesulfonate

into 2 both in 29% yields conditions.

was obtaimd

n-octyl

(R2=p-TOI) could

with 3 (23% and 14%, respectively) p-nitrobenzenesulfonate

2 was not obtained

was

under exposed

be

the same to

the

at all but 3 was formed in 64% yield.

(5) It was found that potassium iodide (KI) is also effective additive but NaBr is not. did not proceed at all (6) In the case of n-octyl acetate and n-octyl ethyl carbonate, carbonylation and the starting

compounds

were recovered

formed only in 14% yield starting a main product

The desired

but I-octanol

ester 2 was

was obtained

(43%).

OH

OtVlS COOEt

A

both in 72% yields.

from n-octyl trifluoroacetate,

-

COOEt

(R)-(-)-12

(I?)-(-)-13

r4B = -41.68”

COOEt *

Pd cat. Nal cat.

p=

y -

&COOEt

COOEt

I\/ 35%

[u]h” = -32.07O (c 1 .Ol,CHCI,)

(c 1.07, CHCI,)

&COOEt

/L

CO, EtOH

[a]&

o”

(c 1.02, CHCI,) CO, EtOH Pd cat. Nal cat.

COOEt e

COOEt

A

(S)-(+)-13

(S)-(+)-12

[a]$‘= 34.310

[u]b= 25.27”

[alp = 0”

(c 1.09, CHCI,)

(c 1.lO, CH&)

(c 1.05, CHQ)

(Received in Japan 1 March 1991)

34%

as