Reactions of cyclic disulfides with carbenes; desulfurization and insertion

Tetrahedron Letters,Vol.26,No.42,pp Printed in Great Britain

REACTIONS

OF CYCLIC

DISULFIDES

DESULFURIZATION

Wataru

Yorio

Ando*,

Reactions

catalytic

and photochemical

studied.

Carbenes

quantitatively

as S-S insertion

in the reaction

reaction

is sensitive

The influence the reaction

carbene

cyclic with

with

B-elimination

carbene

known

carbenes

to afford

of S-S insertion

detail

studies

Scheme

There

involve

olefin.

+

One uses the cyclic

fides with

&cfi /\""a R' R'

disulfides

can be realized. carbenes

in which

by

have been

1,3-dithiane desulfurization The carbene

/j

very

often

changes

is in ability a few reports

to vast

amount

that the reaction

affords

the sulfur

Diary1

a

to have on the

of sulfide-

of dialkyl

ylide

followed

by

disulfide ineffficiently reacted 1,2 product. Of the few examples

insertion

R-f-S-C<;:'

I

possibility

reaction

of acyclic 3-5 dithiaacenaphthene.

:CR2 -

generated

substituents.

been only

on the reaction

1

R-S-S-R

have

shown

predominantly

the S-S

compounds

problem

in contrast

carbenes.

to give

carbenes

the selective

of carbnene

We have already

reactions.

disulfides

Japan

yielding

bulky

of this general

ylide.

with

with

while

with

of Tsukuba

305,

of diazo

Takata

of disulfides.

effect

Typical

of sulfur

of disulfide

Ibaraki

disulfides

reaction,

of disulfides

of steric

and Toshikazu

disulfides

cyclic

to bulkiness

courses.

B-elimination reaction

with

CARBENES;

University

decompositions

reacted

results

Kumamoto,

cyclic

of several

WITH

INSERTION

Niiharigun,

Sakuramura,

Summary:

AND

of Chemistry,

Department

oo4o-4039/85 $3.00 + -00 01985 Pergamon Press Ltd.

5187-5190,1985

1

in the reaction

Here we report the selective

5187

disulfide

R-S-CH

with

carbene,

no

/R' (R=alkyl)

'R'

I (RS)2C;R

(R=alkyl,aryl)

R'

of carbene,

the reactions

S-S insertion

a number

of cyclic

of

disul-

and desulfurization

5188

took place

depending

In a typical

on both

the structures to a mixture

procedure,

of disulfides of 1.1 mmol

and carbenes

of

used.

cc-lipoic acid methyl

ester was

in 10 ml of dichloromethane -1 and 2.6 mm01 of diphenyl diazomethane Nitrogen at room temperature. added 0.02 mmol of cuprous chloride

evolution CuCl,

ceased

in two to three

and the products

were

benzene).

dithiane

1 was obtained

along

with

Table

1

Run

1

separated

The stable

(eluent:

The mixture

hours.

sulfur

unexpectedly

by silica ylide

gel column

as the S-S

Reaction

of Cyclic

at Room

Temperature

Diazo

WCo2Me s-s

1

Disulfide

Compd.

N CPh 2 2

with

Carbene

insertion

1,3product

CuCl

and Yield(Conv.

Yield)

0 0 -76) 100"/(1008)

WCOzMe L/S 0

&

-2

N2CPh2

fv-

CuCl

87)

68%(100%)

-g8)

66%(100%)

P+;h

0 Gk S-S

kk

but

in Dichloromethane

Product

Catalyst

0

3

chromatography

can not be isolated

high yield

to removed

tetraphenylazine.

Substrate

2

was filtered

s-s

7

3

N2CPh2

CuCl

%V s s PhXPh

-4

N2CPh2

CuCl

>8(

-4

N2CPh2

4

N2C(C02Me)2

hvb)

-4

N2CHC02Et

CuCl

S

CRh(OAc),lza)

0 Yk s

s

-10

28%(100%)

-10

29%(100~)

-10

33%(100%)

-11')

69%(69%)

12

30%(100%)

-12

29%(100%)

-13

89%(89%)

Hxco2Et 8 9 10

0

0

9-k

5

N2CPh2

5

N2C(C02Me)2 hvb)

l-3 s-s

5

N2CPh2

s-s

a) 0.01 equiv. of [Rh(OAc)2]2 irradiation

0

CRh(OAc)212a) >wc S

n

CuCl

Pzx;h was added

with high pressure mercury

to disulfides.

b) Carbene was generated

lamp in Pyrex tube.

by

5189

Analogous

reactions

cr-lipoic acid methyl yield

but higher

contrast

were

conversion

attempted

using

The formation

ester.

yield,

disulfides

of 1,3-dithiane

probably

by steric

2 and 3 in place of is somewhat lower

effects

on sulfur.

In

4 reacted with diphenyl diazomethane -l-3 _I the disulfide _ of cuprous chloride unde.r the same reaction condtions as those

to disulfides

in the presence

The desulfurization product, thietanone -10. 10 was also obtained from the reaction of the disulfide 4 In turn, the reaction with carboethoxycarbene biscarbomethoxycarbene.

employed

with 1 yielding

thietanone with

caused

the formation The reaction

carbene

These

of thietanone

diphenylcarbene

formation.

or biscarbomethyoxy-

-12 in 30% yield along with 70% of recovered The 1,3-dithiepane 13 was obtained as a sole (Run 8 and 9).

in 89% yield

results

in the reaction

clearly

indicate

sterically

hindered

generating

method

of carbene.

with

less hindered

may

2 with

gave thiolane

substrates product

11, but none

of 1,3-dithiane of disulfide

consist

S-elimination

product

We now propose in scheme

disulfide

of disulfide

The formation or highly

in the reaction

(a type),

or with

of S-S

of cyclic

formation

insertion

carbene.

both

on the product

There

11 is no

disulfide.

involve

the sequence

followed

the b type rearrangement occurs in hindered type rearrangement in less hindered one.

of steps

by 1,3-rearrangement

C-S bond cleavage

Clearly

Scheme

diphenylcarbene. requires

it does not depend

reactive

reactions

ylide

5 with

the desulfurization

and carbene;

that these

2, name1.y sulfur

S-S bond cleavage

that

(b type).

sulfur

ylide,

2

1 R* R*

R* R*

and _ a

shown with

5190

REFERENCES

AND NOTES

I) W. Ando,

Act.

2) w. Ando,

T.Yagihara,

Chem.

and T. Migita,

Res., lo,

J. Org.

Chem.,

3) A. Schiinberg and T. Stalpp, 4) L. Field

and C. H. Banks,

5) s. Tamagaki 6) 2: mp.

and S. Oae,

66-67°C.

33.9(t),

37.

1721

Chem.

J. Suzuki,

Chem.

63,

Sot.

24.8(t),

51.5(q),

T. Toyama,

S. Nakaido,

(1972).

Ber.,

J. Org. Chem., Bull.

42.7(d),

144.2(d),

7) 8: IR(cm -l,KBr)

I. Imai,

13C NMR(6,CDC13)

35.5(t),

141.4(d),

179 (1977).

S. Tozune,

3102

40,

(1930).

2774

(1975).

Jpn., 45, 25.6(t),

64.5(s),

960

(1972).

29.9(t),

127.3(d),

32.3(t),

128.6(d).

130.3(d),

173.9(d).

1695(C=O).

'H NMR(G,CDC13)

1.53(s,6H),

3.66(s,2H),

7.51-8.11(m,lOH). 8) 2; mp.

95-96°C.

1_53(s,6H), 23.1(q),

23.3(q),

128.7(d), 9) 11; mp.

IR(cm -1,KBr)

1.97(s,3H),

27.4(q),

143.6(s), 109-110°C.

4_31(q,2H), (Received

157O(C=C),

2_01(s,3H), 53.1(s),

146.9(s),

1 August

65.1(s),

125.0(s),

'H NMR(6,CDC13) 13C NMR(6,CDC13) 127.7(d).

128.0(d),

200.4(s).

'H NMR(cS,CDC13)

4.96(s,lH). in Japan

1665(C=O).

7.50-8.09(m,lOH).

1985)

1.33(t,3H),

3.62(bs,3H),

3.68(bs,3H),