Sulphenate ions as ambident nucleophiles

TetrahedronLetters No. 43, PP 3783 - 3784,

SULPHENATE

IONS

AMBIDENT

AS

and R. Hogg" of Chemistry, Aberdeen

Donald Department

PergamonPress. Printed in Great Britain.

1974.

NUCLEOPHILES

Alexander Robertson University of Aberdeen, AB9 ZUE.

(Received in UK 19 August 1974; aoceptedfor publication18 September1974)

Interest by

their

the

facile

the

has

The

anions

now

4

as

observed

aqueous

dioxan

5

attributed

of

Addition almost 1215

the

in

and

more

evidenced

by

sulphenate

the

us

3

reported

excess the

nmr

which

1208

thiolate

anion.

1 with at

standard,

the

labile

on

ion

Addition

by

F nmr

disulphide

with

relative

1263

ion

Hz

this

3703

the

ambident

disulphide stability

of

the

detection.

and

in

downfield

from of

2:l

respectively.

signals

very

30%

intensities

to

sulphate

the at

the

more

than

fluorosulphonate

at

swl-

similarly slowly as

is noteworthy

is faster

and

methyl

sulphoxide It

solution

1208

reacted

much

methyl

respectively.

of methyl

Hz

comparison

reacted

reagent

penicillin

acidified

ttio main

sulphide

only

0-silylation

(0.03M)

and

by

for

by

+ H20

Dimethyl

iodide

of methyl 1172

higher

1289

showed

respectively.

and

19

sulphenate

assigned

methyl

the

fluorosulphonate

spectrum were

to

+ ArS-

signals

of methyl

contrast

at

owing

and

recently

but of

to report

of using

(0.25M

gave

and

a mixture

signals of

ion

2:l

In

gave

Until

rearrangement

prompts

= ArSO

internal

sulphenate

slowly. and

methylation

the

and

ratio

methyl

thermal

convenience

hydroxide

thiolate

the

been

stimulated

derivatives'

2

sulphoxides. had

anions

+ 20H-

30 min.

a lo-fold

(36 min.)

the

sodium

immediately Hz

phide but

of

and

sulphenate

and

ion,

to

the

of penicillin

been

of bis(2-nitro-4-trifluoromethylphenyl)

5

after

trifluoroacetate

atom

has

hydrolysis

ArSSAr of

sulphur

to

RSOH,

anions.

series

Reaction

reactions

esters

by

acids,

sulphenate

a source

this

their

the

sulphenic

in

generated

been

of

alkaline

in

of of

acid

nucleophilicity

of

intermediacy

reactions

sulphenic

used

chemistry

rearrangement

sulphoxide

was

the

postulated

nucleophilic of

in

that

methylation the

beginning

of of

No. 43

37a4

the

hydrolysis

phenate

did

formation

not does

intercept not

These iodide gave

gave

only

were

the

the.sulphide

low

yield

of

the

the

gave

anions

therefore

alkylating

agents

predominantly at

that

methyl

sul-

ion.

the

was

ArS-OMe

isolation

sulphoxide,but

the

harder

soft

of

the the

sulphoxide sulphoxide.

during

anions 6 in reacting

sulphur

oxygen

of

to hydrolysis

sulphinate

at

yield

atom

Methyl

mole).

fluorosulphonate

a trace

relative

attributed

(0.01

methyl

and

(15%),

a greater

resemble

the

* 4

product

sulphenate

sulphenate

predominantly

demonstrated

or methoxide

Me2SO

by

and

Sulphenate

reagents

and

MeS03F ArSO-

sulphide

sulphate

anions

methanol

confirmed

(98%),

Dimethyl

(
results

involve

Me1 f--

ArSMe

the

but

with

workup. with

soft

harder

atom.

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