Trifluoroacetoxysulphenylation of unsaturated nitriles as a route to lactones

Tetrahedron Printed in

Letters,Vo1.27,No.43,pp Great Britain

0040-4039/86 $3.00 + .OO Pergamon Journals Ltd.

5293-5296,1986

TRIFLUOROACETOXYSULPHENYLATION

OF UNSATURATED

NITRILES

AS A ROUTE TO LACTONES K M Abtl El Samii, Mohamed

Zakaria

Department

of Chemistry,

I Al Ashmawy

The University,

and John M Mellor*

Southampton

SO9 5NH

Abstract Use of manganic acetate as oxidant permits efficient trifluoroacetoxysulphenylation of unsaturated nitriles with organic disulphides. The adducts in a cobaltous chloride promoted hydrolysis afford alkyl- or aryl-thio substituted lactones. In the preceding

paper' we describe

two important

for hydroxysulphenylation

of alkenes.

replace

as the oxidant

lead tetraacetate

in particular control

unsaturated

In seeking

acetate

other functionalised

alkenes.

unsaturated

a process which

nitriles

used instead afford

acetoxysulphenylation to an important

of unsaturated

class of substituted

Trifluoroacetoxysulphenylation 1-ene (3)4 using diphenyl disulphide manganic

promoted

(6) was effected

acetate

in

nitriles

of the trifluoroacetoxysulphides

mixtures

of hydroxysulphides

nitriles acetate Unlike

in Table

could be isolated.

is observed

lower regioselectivity.

trifluoroacetoxy

by hydrolysis

(of acetate

sulphides

and hence the procedure provides

group,

is

readily

of trifluoroa novel route

disulphide

(2)3 and 5-cyanopent-

(5) and di-n-propyl acid (4:lj

Results

from Markovnikov a hydrolysis

with

are shown in Table

1.

and anti-Markovnikcv under basic conditions

The hydroxysulphides

were readily

(7-24) shown in Table

separated

1 satisfactory

that whereas

trifluoroacetoxysulphenylation

(55-85%)

the additions The observed

lead tetraacetate

of hydroxysulphides

to be isolated

of esters of allylic

to these unsaturated regioselectivities

alcohols

nitriles

of unsaturated

the use of manganic after hydrolysis. where high regio-

are characterised

might be controlled

an effect apparent

in

additions' 5293

to allylic

acetates.

by a

by the electron

withdrawing inductive effect of the substituent nitrile group, an effect apparent in 1 or by a neighbouring group participation additions to the allylic trifluoroacetates, nitrile

to

data were obtained.

the trifluoroacetoxysulphenylation

selectivity

derived

in only low yield using

good yields

regio-

additions

when manganic

(l), 4-cyanobut-1-ene

on work up, or following

1 establish

can be effected permits

followed

and for all the hydroxysulphides

and spectroscopic

permit efficient

alkenes

the hydroxysulphenylation we have examined

as the added oxidant.

could be isolated

The results

vicinal

(4) di-p-tolyl

addition

analytical

functionalised

lactones.

Mixtures

by chromatography

which

dichloromethane/trifluoroacetic

or lead tetraacetate

can advantageously

Secondly,

more efficient

hydrolysis

of ally1 cyanide

disulphide

acetate

Trosr procedure

the trifluoroacetoxysulphenylation

is markedly The adducts,

on cobalt chloride

to extend

and lead tetraacetate

Here we report

of lead tetraacetate.

lactones

of the disulphide.

esters may be used in procedures

based on manganic

of the original

We find that manganic

of the hydroxysulphenylation.

procedures

extensions

We tentatively

by the

2

5294

Table Hydroxysulphides

from

Addition

to

Unsaturated

Added Oxidant

Alkene

1 Nitriles. Markovni Product

Disulphide

kov (Z)a

Anti-Markovnikov Product (%)a

7

(20)

8

(66)

5

9

(15)

10

(73)

6

11

(11)

12

(46)

13

(28)

14

(47)

I

Mn(OAc)3

4

1

Mn(OAc)3

1

Mn(OAc)3

2

Mn(OAc)3

4

2

Mn(OAc)3

5

15

(36)

16

(47)

2

Mn(OAc)3

6

17

(24)

18

(49)

3

Mn(OAc)3

4

19

(42)

20

(14)

3

Mn(OAc)3

5

21

(50)

22

(14)

3

Mn(OAc)3

6

23

(72)

24

(5) (18)

1

Pb(OAc)4

4

7

(3)

8

2

Pb(OAc)4

4

13

(9)

14

(12)

1

Pb(OAc)4

6

11

(3)

12

(15)

2

Pb(OAc)

6

17

(7)

18

(24)

a Isolated

4 yields

after

chromatographic

separation

OH

SR

(_

(CH2jn CN

RS

HO

7

R=Ph;

9

R=pMeC6H4;

11

R=nPr;

13

R=Ph;

(CH21n CN

+

n=l

8 n=l

n=l n=2

I5

R=pMeC6H4

17

R=nPr;

19

R=Ph;

21

R=pMeC6H4;

23

R=nPr;

;

n=2

n=? n=3

SR

n=3 n=3

&A

SR

R=Ph;

n=l

10

R=pMeC6H4;

12

R=nPr;

14

R=Ph;

16

R=pMeC6H4

n=l

n=l n=2

18

R=nPr;

20

R=Ph;

22

R=pMeC6H4

24

R=nPr;

;

n=2

n=2 n=3

;

n=3

n=3

f-Q0

SR

25

R=Ph

28

R=Ph

31

26

R=pMeC6N4

29

R=pMeC6H4

32

R=pMeC6HS

27

R=nPr

30

R=nPr

33

R=nPr

R=Ph

5295

Table 2 Cobaltous Starting

Chloride

Promoted

Hydroxynitrile

Product

7 8 9 10 19 20 a Isolated conclude Hence

25 25 26 26 28 28

effect

effect

is the major

addition

These results

other trifluoroacetoxysulphenylations,

because

purification the observed

of anti-Markovnikov

normal Markovnikov

by the remote substituent.

(%)a

70 93 85 87 86 90

factor controlling

leads to the dominance

but in 5-cyanopent-1-ene

transmitted

Yield

yield of pure lactone after chromatographic

that the inductive

this inductive

cyanide

Lactonisations

addition

is observed

to ally1

as little effect is

cannot be effectively

of the limited available

selectivity

compared

with

data for this reaction

but afford an interesting comparison with other additions leading to sulphenylation. In 5 6 sulphenolactonisation involving unsaturated esters or acids,6'7 processes noted to be 9 8 characterised by a number of disadvantages, sulphenoetherification and sulphenocycloamination the observed

regiochemistry

neighbouring Access

to the hydroxynitriles

substituted recent

is substantially

lactones,

synthetic

of regioisomers

(7-24) suggested

compounds

interest.

The success

of the participaticg

the efficient lactones.

conversion

Hence

two step process the subsequent

by addition

to hydrolyse in aqueous

of regioisomeric

depends

the nitrile

cobaltous

pairs to single alkylthio-

the successful

of trifluoroacetoxysulphides

conversion

of nitriles

Cobaltous

chloride

ordinated

nitrile

formation

of the mixture precedent

on whether

formation

of regioisomers

nitrile

functionality.

chloride,

in Table 3 we report

and arylthio-

yet the subject lo of

to an unsaturated

of initial

There is good literature

of Warren's

chosen

of reactions

route to alkylthio-

in the literature,

of such a route clearly

e.g. (7) and (8), obtained

2 the consequence

hydrolyses

by the demands

a possible

not well reported

the same lactone under conditions in Table

determined

group.

conditions

or arylthio

of lactones

We report which

permit

substituted

obtained

using manzanic

to a single

the pairs

both afford

by the

acetate

and

lactone.

for our observations. A number of metal ion promoted 11 and cobalt salts are particularly efficient.

have been reported

has been used to promote intramolecular nucleophilic attack at a co12 Secondly it is well established from the recent work group previously. 13 that under acidic conditions phenylthio migration permits a number of group

useful

transformations

afford

lactones

including

via episulphonium

participation

Of the three types of lactone described (3H) ones (4-substituted

butyro

by a neighbouring

ester functionality

to

ion intermediates. in this paper the 4-substituted-4,5-dihydrofuran-2-

lactones)

(25-27) are the most well known because

relationship

of their

to butenolides. Although other syntheses of 4-thio substituted butyrolactones 10,14 The have been reported the present method seems advantageously simple and direct. other lactones

(28-33) have not been previously

reported.

5295

Additions

using phenylsulphenyl

trast to the widely of

phenylsulphenyl

chloride

promoted

chloride

used phenylselenyl chloride

have not been used to give such lnctones The disadvantages

chloride.

make this alternative

lactonisation

a valuable

associated

mode of hydroxysulphenylatinn

extension

to the important

in con-

with the use nnd cobalt

are<+ in synthesis

of

sulphenolactonisation. Table 3 Two Step Conversion

Disulphide

Alkene 1 1 1 2 2 2 3 3 3

4

Channel

Scheme,

References 1.

7and 9 and 11 and 13 and 15 and 17 and 19 and 21 and 23 and

; 4 ; 4 5 6

a Isolated Acknowledgement

of Unsaturated

Nitriles

tc Lactones

Alcohols Affording Intermediate Trifluoroacetates

Lactone

8 10 12 14 16 18 20 22 24

25 26 27 28 29 30 31 32 33

yield of pure lactone after chromatographic

We thank the Egyptian and ?Irs J Street

Education

for n.m.r.

Yield

Bureau

(%)a

65 65 61 __

:>

ii 69 85 73 80

purification

for financial

support

through

the

spectra.

and Notes

Z K ?1 Abd El Samii, M I Al Ashmawy

and .J M Mellor,

and P G McDougal,

preceding

2.

B X Trost, M Ochini

3.

M Podzimkova, M Prochazka and M Palecek, Collect.Czech.Chem.Commun., 1969, s,2101. was prepared following the method of A P Krapcho and A J Lovey, Tetrahedron Lett., 957 from the appropriate u-cyanoester.

4.

F B LaForge, N Green and W A Gersdorff, J.Am.Chem.Soc., pared by the method of Krapcho and Lovey (see ref.3).

5.

P A Bartlett, 'Asymmetric Synthesis' Press, Xew York, 1984. J.Am.Chem.Soc.,

J.Am.Chem.Soc.,

paper.

~01.3,

chap.6

3973, 100, 7103.

1948, s,

3707.

(2) 1973,

(3) was ,)rf-

(Edited by .J II Morrison),

Academic

6.

De youra Campos,

7.

Nicolaou and 2 Lysenko, J.Chem.Soc. Chem.Commun., 1977, 293; ti C Nicolaou, S P Seitz, J Sipio and .J F Blount, J.Am.Chem.Socl, 1979, 101, 3884; R N Young, W Coombs, Guindon, J Rokach, D Ethier and R Hall, Tetrahedron Lett., 1981, 2, 4933.

1954, 16, 4480.

8.

Capozzi,

V Lucchini, F Marcuzzi and G Modena, J.Chem.Soc.

9.

Ihara, Y Haga, M Yonekura, 1rl(; "J, 71/.q ld-,,.

K Fukumoto

J.Am.Chem.Soc.,

1983,

10.

R Tanikaga,

I I Creaser, J MacB Harrowfield, 3559 and references therein.

F R Keene and A ?I Sargeson,

12.

Y Fukuoka and K Sasaki, E, 170109c).

Patent

13.

V K Aggarwal and S Warren, ibid, p.765.

14.

M Watanabe, K Shirai and T Kumamoto, Bull.Chem.Soc.Jpn., 1979, 52, 3318; I' Brownbridge, E Egert, P G Hunt, 0 Kennard and S Warren, J.Chem.Soc. Perkin Trans.L, 1981, 2751; P Brownbridge, P G Hunt and S Warren, Tetrahedron Lett., 1983, g, 3391. in

UK

18

and A Kaji, Synthesis,

and '1 Kametnni,

1981, 3106.

11.

(Received

H Yamashita

T Ohsawa,

Perkin Trnns.1,

Japanese

Tetrahedron

August

1986)

1986, 416.

10th July Lett.,

J.Am.Chem.Sorl_,

197i, 74,26,621.

1986, 2,

101;

1981, 103,

(Chem Abs.,

M Hannaby

1971,

and S Warren,