Reaction of enamines with γ-bromo-αβ-unsaturated esters

Pergamon Press Ltd.

Tetrahedron Letters No.15, pp. 959-961, 1965 printed in Great Britain.

FMCTION OF BNAMIIESWITHd -BROMO-q/3-UNSATURATED ESTWS Amareshwar Chatterjee Department of Chemistry Jadavpur University, Calcutta-32, (Received 16 February 1965)

India

Since enamines have been shown to react halides,

c( -haloesters

interest

to see how they would behave with 3 -brono-o!&unsatu-

rated this

esters.

andaCp-unsaturated

with ally1 it was cbi

The author is not aware of any attempt made in

direction. As a model study methylf

allowed

to react

with

nndqr refluxing a liquid

material

-bromocrotonate

cyclohexanone

condition. boiling

52 per cent yield

After

enamines usual

at l18-122°/0.4

as the main product2

has been confirmed

I+1

-

II

(III)

a

/

and workup,

was established

in The

from

to be the normal

the following

0

reasons:

/ a

0

CH2.CH=CH.C02Me

cn2

xu

1. The compound contained colouratlon

for

in benzene

of the reection.

TLC and the structure product

(II)

mmwas isolated

OS the material

alkylation

(1) was

hydrolysis

homogenooas character

0

este&,

.co2hte

(CH&.COpR

H

no b&mine and did not produce any

with tetranltromethane.

959

No.15

960

2. It showd UV absorption (6 112) In ethanol, and broad)

infra-red

and 1670 cm-l

unsaturated

and 288 mp

(CC141 bands at 1722 (strong

(medium) characteristics

of o@

aster.

3. It furnished 365 m/(6

at 212 m)t(E 10,230)

DRP (MeOH-EtoAc), m.p. 146-147’,h,,x

24120) and seaicarbazone

-

CHC13

(MeOH), m.p. 169-170’

in very low yields. 4.

On catalytic

reduction

(Pd-C),

the compound absorbed

one

mole of hydrogen per mole to give only the saturated ester EtOH (IV, R=We), (6 421, strong infra-red (CC14) h ulax 283 m /Gbands at 1745 and 1720 cm’1 . This reduced ester produced a DRP (MeOH), m.p. 112’ in quantitative 5. The ester

(IV, R=Me) on acid or alkaline

ded the keto acid 60-610), alone

(IV, R=H), m.p. 60-61’

semicarbazone

m.p. 185-187’

or mixed with authentic It is interesting

acid

yield.

hydrolysis

characteristic

hydrolysis

(reported3

(reported3

affor-

m.p.

m.p. 185-187’)

samples.

to note that the ester

did not suffer

any molecular

of some E -keto

acids

(IV, R-Me) on

rearrangement4

reported

by Her&’ and

Banerjee’. The carbonyl ly inteuse group.

band of

near 288 m is significant/Lc (see above) than the value expected for normal carbonyl

This may possibly

exchange Interaction

be due to some type of intramolecular

may be satisfied

the side chain. poor yields

between the C=O and the double

reaction’

bond in the compound (III); interaction

(III)

groaetrical

condition

only by the axial

The C=O in (III)

is definitely

of DNP and semicarbasone)

for this

orientation hindered

Of

(very

but the double bond

No.15

behaves

normally Studies

ring

on catalytic

now In progress

hydrogenation. with

enamines

and r-bromo-&,&unsaturated

ferent

steric

pound

of the under

least

are

systeas

also

at

considerations. type

(III)

of other

esters

of dff-

The transformation

to the

bicycle

of the

octane

system

com-

(V) Is

investigation.

AcknowledaPzeat The author encouragement

wishes

and Prof.

to thank

Prof.

Gilbert

B. K. Bhattacharyya

Stork

for

for

valuable

discussion.

1.

G. Stork,

A Brizzolara,

and R. Terrell, 2.

All

H. Landesman,

J.Am.Chea.Sog,

compounds

reported

here

s, gave

J.

Szmuszkovlcz

207 (1963). satisfactory

analytical

results. W.

3.

J.

Cook and C. A. Lawrence,

4.

Compare,

W. Rerz,

5. w. Herz, 28, 6.

m,

J.Am.Chm.,

2529

M, a,

2,

1485

817 (1937). 630 (1957) (1956);

W. Herz,

Ibid.,

(1956).

D. K. Banerjee

and T. R. Kasturi,

J.Am.Chem.Soc.,

2,

926 (1957). 7.

G.P.

Kugatova-Shemyaklna

hedrw,

g,

J.Chem.Soc., J.

Hudec,

697 (1962); 2302

(1956);

-._&Q$_&&,

and Yu.A.

Ovchlnnlkov,Tetrahe-

R.C.Cookson R.C.Cookson, 589 (1961).

and N.S. R.R.

Wariyar, Hill

and