Stereoselective synthesis of cis or trans N-phenyl 2-phenyl decahydroquinolin-4 ones by catalyzed hetero-Diels-Alder reaction.

Stereoselective synthesis of cis or trans N-phenyl 2-phenyl decahydroquinolin-4 ones by catalyzed hetero-Diels-Alder reaction.

Tetrahedron Printed Letters,Vol.27,No.26,pp Great Britain in STEREOSELECTIVE SYNTHESIS DECAHYDROQUINOLIN-4 ONES Christine VEYRAT, Laboratoire...

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Tetrahedron Printed

Letters,Vol.27,No.26,pp Great Britain

in

STEREOSELECTIVE

SYNTHESIS

DECAHYDROQUINOLIN-4

ONES

Christine

VEYRAT,

Laboratoire

: --Cis

Summary

or

trans

de

OF

CIS

WARTSKI,

Carbocycles,

TRANS

Jacqueline

91405

2-phenyl

N-PHENYL

$3.00 Journals

+ .OO Ltd.

Z-PHENYL

HETERO-DIELS-ALDER

associe

Paris-Sud,

N-phenyl

OR

BY CATALYZED

Lya

des

Universite

0040-4039/86 Pergamon

2981-2984,1986

REACTION.

SEYDEN-PENNE*

au

CNRS,

ORSAY

Bat.

CEDEX,

decahydroquinolin-4

420

France

ones

can

be

synthesized

highly

selectively.

The

use

of

process.

Recently,

a-enones

has

field,

there

present

silyloxydienes the

been is

study

Diels-Alder

report, the

largely

to

our

synthesis

increased

reaction

between

(1). However

examined

no on

has

of

the

despite

knowledge,

the

the

on

the

decahydroquinolin-4

synthetic

silyl

intense

enol

ether

of

activity

using

of

the

Diels-Alder

cyclohexene

acetyl

in the

of -I with

reaction ones,

potentiality

J

(2,3)

hetero-Diels-Alder

imines.

We

shall

benzylidenenaniline

and

focus

_2 as

the

hetero

dienophile.

QY I /

OSiMe

-1

No

reaction

temperature CH2C12

or in

the

diastereoisomeric obtained,

after

took

at

reflux

presence & basic

3

place

without

Lewis

methylene

various

decahydroquinolin-4 hydrolysis

NPh

-2

(toluene, of

PhCH=

and

Lewis

acid ones

treatment

acid

catalysis

chloride,

in

different

acetonitrilel.

using

a slight

excess

2 and

4 besides

small

by

2981

Et3N/MeOH

solvents

When of

the

diene

amounts

(treatment

either

reaction (I,2

eq),

of trans A).

at was

room run

a mixture isomer

in of

> were

2982

The MHz)

structural

according

assigned

to

after

6

and

the

the

treated

of

on

H-2

product

enoxy-silanes by

rely

(4) in

lead

( UC0

and

and

H-9

‘H NMR

WI/2

(H-9

spectra

and

(250

H-IO

or

signals

500 being

. solution

1 could to

= 1715 cm-‘)

constants

CH2C12

6 and

NEt3-MeOH

IR

coupling

treatment)

reaction

B), two 1

values

Et3N/MeOD

When (treatment

assignments

3

be

and

was

treated

characterized

2

in

similar

by

by

aqueous

250

MHz

HC03Na

and

NEt3

‘H NMR.

Mixtures

of

time

temperature

ratios.

Ph

I

H

h

\Ph \ Q

OSiMeg

OSiMeg ?

-6

The (see

3/4

-

ratio

depends

on the

nature

of the

Lewis

acid

and

on the

reaction

and

table). When

HC03Na

the

reaction

treatment,

2

was

was

performed

obtained

next

with to

a

TiCI

(1 eq)

mixture

of

for

40

mn

enoxy-silanes

and

_6

followed and

_7

by in

aqueous

the

ratio

gives,

after

>/&/?25/2/73. With treatment

TiCl 4 (3 by

aqueous

eq)

or

HC03Na,

ZrC14 only

(3 eq) 2.

respectively

for

I h or 2 h 40,

the

reaction

2983

Furthermore, water

and

MeOH

followed

by

when

the

treatment,

water

3

quenching

reaction

was

was

isolated

gives

run

with

(70%).

respectively

a

BF3.Et20

Treatment

(1 eq)

of 3

mixture

of

2,

by

I eq. Tic14

by

5, 2

followed

next

to

5

washing

during or

with

Ih or

only

18h

2.

Ph

w I HN

Ph

1

0

-a

Substances kinetic while

control under

control

6

in

the

reaction

the

way

take a

to

are

2.

used

enolates

kinetic

as

Lewis

: it is known to

these

might

of

decahydroquinolin-4

ones

whatever

predominant

the

via

Danishefsky

the

reaction

catalyst 10,

: related

equilibration to

of

(entries

process

according

these

intermediates

ring fused from

silyl

experimental

ratio

products

(entries

II).

Such

examples a

process.

a

I, 3,

4,

7,

8)

thermodynamic

have

silyloxonium

Under

been

recently

intermediate

(6). Further

experiments

to &

fused

on

are

under

possibilities.

result

that

70/30

primary

retro-Diels

of the tranS

(7)

the

(5). However,

be invoked of

be

highly

e

protonation

acids

a

_7 is

Diels

also

to

in

reaction

one

The formation

According 2-phenyl

formed

by

can

strengthen

appear

control

place

pathway

1

1. are

homo-Diels

The 3 and

and

and

thermodynamic

could

published

6

enol conditions

can

be

leads

compound

protonation ethers the selectively

are

2, which of

the

cleaved

stereoselective performed.

takes

equilibrating into

titanium synthesis

ring place

bicyclic

when

TiCI

zirconium

or

enolates of -cis

by or

trans

ketones or

ZrC14

titanium TiC14. N-phenyl

-

2984

Table Reaction Entry

Lewis

acid

(I eq.)

of 1 with

tot

2

in

CH2C12

time

treatment

3/4(a)

(Yield

%(b))

I

BF3.Et20

-78

5 mn

67/33(‘)

(0

2

BF3.Et20

0

5 mn

55/45(d)

(f)

3

BF3.Et20

20

I h 30

70/30(d)

72

4

AIC13

3 h 30

70130

(0

5

AIC13

20

5 mn

55145

If)

6

AIC13

20

I h 30

IO/90

60

7

Et2AICI

20

I h 30

70130

41

8

ZrC14

5 mn

70130

(f)

9

ZrC14

20

I h

40/60(C)

(f)

10

ZrC14

20

4 h 30

l/99

50

11

TiCI

20

5 mn

2198

(f)

a) -3/4

ratio

crude

-10

-40

determined

crystalline

f) Next

(e)

to

by

product.

adducts,

‘H

c) -3/4

starting

on

ratio

the

crude

deduced

materials

: We thank

Acknoledgments

NMR

were

crystalline

from

6/7 --

product.

ratio.

b)

Yields

d) Traces

determined

of &. e)

0.1

on

eq.

the

BF3.Et20.

observed.

Rhone-Poulenc-Agrochimie

for

financial

support

of

this

research.

References 1)

F.

RICHTER,

H.H.

2)

M.

WEINREB,

R.

3)

J.F.

KERWIN,

4)

All with mp

new

Jr.,

= 142

BARTLETT,

6)

S.J.

DANISHEFSKY, 1256

Tetrahedron,

correct

structures. ethyl C.

Letters, 38,

WU, W.H.

3087

Letters,

analysis

(C,H,N),

: mp “C = 167,3

acetate/hexane Org.

Chem.,

PEARSON,

D.F.

4351

(1985).

(1982).

Tetrahedron

elemental _3

J.

2&

2,

3739

IR and

(1982). ‘H

NMR

; 2 : mp “C = 156,8

spectra

in agreement

; 2 : mp “C

144,l

q

; &

recrystallization. 0,

4087

HARVEY,

(1985). C.J.

MARING,

J.P.SPRINGER,

J. Am.

Chem.Soc.,

(1985).

E. NAKAMURA, (.Received

Tetrahedron

DANISHEFSKY,

gave

after

P.D.

7)

S.

proposed

5)

105,

STAIB,

compounds

the “C

OTTO,

in

J.I. France

SHIMADA, 2 May

Y. HORIGUCHI, 19861

I. KUWAJIMA,

Tetrahedron

Letters,

24,

3341

(1983).