Reaction of isocyanides. III - synthesis of β-alkoxy imidoyl cyanides from acetals

Tetrahedron Letters, Vo1.30, Printed in Great Britain

No.2,

REACTION

OF ISOCYANIDES.

~ALKOXY

IMIDOYL

HBl&ne

Unite Avenue

Summary

:

CV-iminonitriles.

Tert-butyl

Litterature of

them

au C.N.R.S.

isocyanide

reports

few

PELLISSlER

no109

several give

- Faculte

with

syntheses

access

to

FROM

and Gerard

Boite

reacts

1989

+ .OO

OF

ACETALS

GIL

des Sciences

D12

acetals,

- 13397

CEDEX

13

of diethylaluminium

(l-8

possessing

et Techniques

MARSEILLE

in presence

of Cu-iminonitriles

imidoylnitriles

0040-4039/89 $3.00 Pergamon Press plc

Ill -SYNTHESIS

CYANIDES

Normandie-Niemen

to afford

However, (9,

AssociGe

Escadrille

pp 171-172,

and

an

chloride,

references

@-hydrogen

cited

or

an

therein).

,@ heteroatom

101. Previously,

been and

a-alkoxyamides

synthesized easy

from

route

in scheme

to

acetals

(11).

and

fl-alkoxy

(Y-alkoxynitriles

isonitriles

in the

Q!-iminonitriles

from

(12)

presence

of

or

@-alkoxycyanoenamines In this

TiC14.

tert-butyl

isocyanide

paper,

and

(13)

have

we describe

AlClEt2

(141

a new

as

shown

1.

RI-

R2 1 R-C/s ‘OR’

-

:C=N+

R2 :=N+ 8’ + -____._d-d-C’ :C=Ni-

AIEt&I

AR3

Q

-GC-c

AR3 ‘N+

No

2

&

I

SCHEME The

assignment

spectroscopic For

data example,

tert-butylhydrogens

CEN

‘H

When b-alkoxy

b

in

can be detected.

Moreover,

in

carbon R1

structure

NMR,

spectroscopy,

to the presence

a quaternary

the

in

correct

full

of cyanoenamine

IR

absorption

1 points

the

of

tert-butylhydrogens Using

of

of 1

is based

upon

the

analysis

of

NMR,

IR and

Raman

(14).

we

observe

can

upfield

identify

Nowever,

a

with

agreement appear

an

singlet the

1.46

at

results

ppm

of

DE

1640

cm

corresponding

KIMPE

(9a)

( ?‘,

-C=N-tBul

to

whereas

the the

at 1 .15 ppm (13). absorption

an absorption

at

at 2213

cm-l

-1

.m the

Raman

spectra

but

no

of compound

of the -C E N groups.

’ 3C

NMR

a signal

can be assigned =

we

H,

the

CY-cyanoenamines3

at

110

ppm possessing

a long

relaxation

time

corresponding

to

to the -C F N.

cyanoimines (Scheme

can

undergo

an

acid-catalyzed

isomerization

II).

“@

*;c_C,CN R2

CC4 SCHEME

171

II

3 ‘NH+-

giving

The

experimental

following

results

obtained

for

acetal

conversion

into

iminonitriles

2

are

summarized

in

the

Table.

TABLE If the

the

use

of

TIC!4

a-cyanoimines

of the

are

AlClEt2

obtained

imidoylcyanides.2

References

or

allows

in

better

is now under

N. TAKA-ISHI,

Y. ITO, A.L.

3 - J.S. SANDHU,

S. MOHAN,

P.S. SETHI,

RAI,

K. KRISHAN,

5 - K. TAKAHASHI, DE

8 - D.K.

each

of

the

isomeric

thea-cyanoenamines.

N.

DE

Lett.

The

nitriles

2

chemical

and 3,

reactivity

KIMPE,

procedures

Int.,

10 - N. DE KIMPE,

R.

KAPOOR,

SANDHU,

L.

10, 149 (1978)

5, 152 (1971).

Indian

148,

J. CHYS,

J. Chem.,

9, 504 (1971).

376 (1976).

DE

N. SCHAMP,

1973, 895.

Svnthesls,

. J.N.

L. DE BUYCK,

VERHE,

R. VERHE,

(1969).

892.

J.S.

R. VERHE,

34, 4040

Ind,fLondon)

J. Chem,

22, 955 (1981)

D. PRAJAPATI,

N. DE KIMPE,

A.L.

L. DE BUYCK,

Tetrahedron

Chem.,

Chem.

Indian

1978,

R. VERHE,

DUTTA,

KAPOOR,

A. SINCH,

Svnthesis,

KIMPE,

7 - F. POC HAT,

b)

that

of

in our laboratory.

J. Org.

S. MOHAN,

9 -a)

yields

investigation

2 - J.S. SANDHU,

6 -N.

preparation

:

1 - T. SAEGUSA,

4 - M.

the

BARUAH,

H. HASMA,

BUYCK,

J.

Svnthetic

Comm.,

N. SCHAMP,

CHYS,

N.

1985,

Tetrahedron,

SCHAMP,

335. 32, 3063

Organic

(19761.

Preparations

and

.

L. DE BUYCK,

J. CHYS,

N. SCHAMP,

Bull.

Sot.

Chim.

Beige.

88,

695

(1979). 11 -T.

MUKAIYAMA,

12 -Y.

IT0.H.

K. WATANABE,

IMAI,

T. SAECUSA,

A. MEOU,

C. GIL,

13 - H. PELLISSIER, 14 - The general To

procedure

a stirred

chloride

temperature It

is then

-2 (t.,

:

;

3H)

25.68

H = 9.62

an

argon

(C=N)

dropwise

(s.,

9H1

Anal.

;

1.80

(CH3,

ahueous

:

Calcd.

cm.,

2HI

;

for

;

in France

20

2979

937.

(1986).

3.40

57.33

: 2970, (s.,

(OCH3)

C 10H,8N20

Septerher

an acetal

mixture

is stirred

carbonate

:

;

3.78

58.76

: C = 65.89

1988)

mmol), 12

solution

in anhydrous

in hexane h.

.

at

After

(10

methylene ml)

at

room

room

temperature.

usual

work-up,

the

get column. 2940,

3H)

(1 mmol)

(1.2

potassium

; N = 15.42.

(Received

1984,

Et2AICI

on a silica

IR (neat)

tBu)

of

reaction

by chromatography

:

27,

(3 mmol)

The

in a saturated

; 29.32

Lett.,

1974, 1457.

Letters,

Letters

:

a solution

atmosphere.

; R2 = H ; R3 = Me

1.46

(CH21

142.04

) is added

is purified

R’ = Et

below

tert-butylisocyanide

ml

poured

cyanoimine

of

Chemistrv

Chemistrv

Tetrahedron

is described

solution

(10

M. SHIONO,

K. SECOE,

2880, ct.,

2830,

1635

1 H) ; 13C

CC, tBu1 ; H = 9.95

;

‘H

NMR

; 86.97

NMR

(CDCI3)

(OCH)

; N = 15.37

(CDC13)

;

: 9.32

: 109.83 Found

:

l.Ou

(CH31 (C-N)

: C = 65.23

; ; ;