A highly regio- and stereoselective synthesis of internal olefins via an elimination of trimethylstannyl group

Tetrahedron Printed in

Letters,Vol.25,No.3,pp Great Britain

A HIGHLY

REGIO-

OLEFINS

AND

VIA

AN

0040-4039/84 $3.00 + 01984 Percamon Press

313-316,1984

STEREOSELECTIVE

ELIMINATION

OF

SYNTHESIS

OF

.oo Ltd.

INTERNAL

TRIMETHYLSTANNYL

GROUP

* Eigoro

Masahiro

Murayama,

Department

Uematsu,

of Applied

Hiroyuki

Chemistry,

Shinjuku-ku,

Abstract:

Internal

thionium

ion

gave

stereoselectivity trialkylstannyl

Some of

time

of

produce

trans

via

or

Macdonald

ago,

reactions

= 0 or

The

resulting

group

finding

to 2)

while that

-

or

produce

and

the

reaction

in

group

in

the

the

high

of

compounds

yield

and

a hydride

carried

having

regio-

p to

transfer modes

of

olefins.

and

the

are

a

b)

bond

a hydride 1)

We

(path

strictly

,2 3

two

formation

to

p to

path

b

- n=3,

4

from

on

n the

PhSm

= 3 or alkyl

the

1 using

predominated when

dependent

the

investigated

derived a)

reaction

found

then

predominated

b

313

internal and

compounds

cyclization (path

the

carbon-carbon

alkyltin(IV)

that

out

electrophiles,

transfer

terminal of

found

@-hydride

path PhS

Japan

with

carbon-centered

reaction

chloride,

his

either

products

ion-induced

2,

olefins

Sato

3,

Ookubo

alkyltin(IV)

1,6-transfer

and

having

cyclization

titanium(IV)

1,5-

University,

160,

secondary

Tadashi

group.

trialkylstannyl thionium

of

internal

tetraalkylstannanes

modes

n

reaction

Waseda

Tokyo

and

Nishio,

when 4. 3) chain

314

length

prompted

Hb-transfer Actually,

us

or

to

cyclization

a hydride

stereoselectivity synthetic

examine

method

in

transfer was

of

whether the with

observed,

internal

there

exists

a selectivity

secondary

alkyltin(IV)

excellent

regioselectivity

and

the

olefins

reaction

with

trans

compounds

turned

out

well

to be

(Scheme as

a useful

4 R

a

= Me,

n=l

d

R = Me,

n=3

e

R

n=4

b

R

= Me,

n=2

C

R = Et,

n=2 Scheme

I.

as

2

Ha-,

geometry.

f

Table

among

Elimination

of

the

I

Secondary

Temperature OC

Alkyltin(IV)

= Me,

Alkyltin(IV)

Product

a)

Compound.

Yieldb)

trans

cis

(sa)

(%)

(%)

100

0

-100

-78

95

9e

2

0

90

91

9

91

80

20

2a -

rt

I()

i-

-2b

0

2?G!

91

84

16

-2c

0

2JG

85

100

0

4d (= 2) -

93

99

1

4e -

96

90

-2d

-78

-2e

0

a)

Chlorides

b)

Yields

2 were

dichloromethane are

based

treated for

with

1 eq

of

titanium(IV)

chloride

15 min.

upon

the

sulfides

before

the

chlorination.

10

in

I).

315

The

secondary

of

titanium(IV)

chloride,

through

Ha-transfer,

while

through

Hb-transfer.

The

1 eq

structure

was

absorption protons

966 cm

observed

in

GLC.

known

routes,

The

reaction and

2b,&, and

_2e

the

at

the

smoothly

at

-78OC,

temperature,

used

The process

the

lower

the

absence in

the

the

Extremely responsible

the

the

the

could

thermodynamically

stable

migrating The

hydrogen

secondary

alkenes

5 as

1 were

treated

alcohols converted in

THF.4)

6

in to

in

with 49

underwent

UV-Irradiation

of

and

4d The

and

the

strong

two

olefinic on

were

prepared

&

4e -

trans

isolated

The

(3)

lower

IR

a by

the

products

group

center

of

and

1,5-

II.

compounds the

the

2a --

The

Grignard or

tosylates 8 by

crude

- 2e

oil

g

the

vs.

the -2~).

cyclization steric

stannyl

group. might

reaction.

be

The

intermediate

high of

group

and

position. were

prepared

compounds to

2 derived

in

when

trimethylstannyl

epoxides

treatment

trans

(2b -

transfer

a cyclic the

The

bulkier

the

proceeded

improved

that

present

nor

reaction

substantial

to

anti-coplanar

aldehydes The

the

bound

assuming

compounds

yields.

to

in which the

became

1,6-hydride

in

by

was

indicate

due

carbanion

Scheme

higher

quite

was

transfer

(4)

however,

would

unfavorable

occupy

the

was

products

1,5-hydride

the

while

selectivity

stereoselectivity.

stannyl

explained

selectivity

trans

required

Among

transfer,

cyclization

better

transfer,

(1)

follows.

The

of

Although

transfer

as

1,5-hydride

(2)

is

of

only

bond.

appropriate

alkyltin(IV)

are

trace

conformation,

the

- 82%

results

any

of

atom

I.

between

samples

with

respectively,

olefins

Table

Hz

to 2

treatment

2,

in view

the

contain

alkyltin(IV)

shown

the

regioselectivity be

of

transfer.

processes

stereoselectivity

and

the

15.2

1,6-hydride

cyclized

high

of

spectra

1,6-hydride

case

in

products

constant

-2d

the

secondary

facile for

major

1,6-hydride

P-position

of

the

temperature.

present

at

not

with

B,

upon

corresponding

s-arized

of

and

double

the

z,

references.

only did

in

on

interaction

the

-2a

and

2,

corresponding

features

inevitably

group

as

olefins

produced

NMR

isomers

2b,

are

of

400-MHz

and

stereoselectivity

-2e

coupling

cis

of

and

results

The

products

observed

-2d

and

the

&,

produced

all

underwent

isomers

compounds

for

modes,

position

alkyl

-1

characteristic

possible

high

assigned

at

preparative the

alkyltin(IV)

with thiophenol

from

from

give from

w-bromo-l-

the

bromides

secondary 6

(76

- 91%)

were

trimethylstannyllithium gave

sulfides

2,

316

LiSnMe, 4 2)

RCH2CH0

or

“‘To

2

ii

X=H

z

X

Scheme

accompanied to

by

thiophenol

diphenyl by

treating

triphenylphosphine. of

the

The an

2 with

of

mixture

overall

byproduct

with

yields

2

in

lithium

of 2

z were

carbon

yield

removed

aluminum

from

in

quantitative

was

as

48

after

reducing

hydride

or

- 5146.

Treatment

tetrachloride

an

almost

it

gave

pure

oil

after

the

succinimide.

present

internal

The

II

N-chlorosuccinimide

sulfides

filtration

the

The

sulfides

a-chlorinated

disulfide.

= Ts

reaction

trans

offers

double

bond

a valuable

into

an

approach

organic

for

molecule

the

introduction

regio-

and

of

stereo-

selectively.

References 1)

T.

L.

Macdonald

and

S.

Mahalingam,

J.

T.

L.

Macdonald

and

S.

Mahalingam,

Tetrahedron

Macdonald, (1981); 2)

Y.

B.

M.

I.

Peterson

3) E.

Trost

Ohta,

E.

Murayama,

and

I.

Fleming,

M.

J.

S.

Filippo,

E.

C.

Ashby in

M.

and

Chemical

(Received

Mahalingam,

Ueno,

Murayama,

the 4)

S.

Uematsu,

Society

of

Jr.,

and

and

Japan

R.

D.

E.

and

M.

Okawara,

A.

O'Dell,

Amer.

Chem.

Chem.

J.

Silbermann, ibid.,

1983)

J. 104,

22,

Amer.

Chem.

m,

Sato, 1983, Amer.

6144

103,

2113

2077

(1980);

(1981);

Sot.,

6529

T.

April

Lett.,

Sot.,

Nakano, Kyoto,

102,

Lett.,

Lett.,

and

Sot.,

Tetrahedron

Tetrahedron

Japan,

DePriest,

1 October

and

J.

J.

Amer.

3,

T.

L.

log,

6767

2577

(1982).

(1981);

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Abstr. Chem.

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No.

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