Allylic organobismetallic reagents - part 1

0040-4039/89 $3.00 + .OO 3955-3958,1989 Maxwell Pergamon Macmillan plc

Tetrahedron Letters,Vo1.30,No.30,pp Printed in Great Britain

ALLYLIC

J.F.

ORGANOBISMETALLZC REAGENTS -

Normant,

Laboratoire Universite

We

have

leading

recently to

bis

electrophiles'

Scheme --

1

have

now

We

postulated

P. et M.

disclosed metallic

J.Ch.

Quirion,

A.

Alexakis

a "metalla derivatives,

extended process

Claisen" which

this is

rearrangement

can

react,

concept

to

the

rearrangement

of

allyl-vinyl

zinc

or

twice,

a

with

case

organometallics the

two

the

newly-formed

of scheme

reagents

variety

of

allyl-allenylzinc

reagents.

The

in -1 reagent

z

-.

Y

-_)

Zn

b 1,

is probably

bonds

of

z\ ==t y

_b

Li

species

once

05

:

/mZnBr

C-m

Masuda

:

-.

in the

and Y.

de Chimie des Organo-eliments, Tour 45 Curie, 4 Place Jussieu F-75252 PARlS Cedex

zL-(y + As

PART 1

is 2

the

real

nature

of m and

m'

a

nonmonomeric cluster. We 1 different , but the problem may

be

thought

of

in

:

3955

terms

a is

unknown,

have is of

shown even

a

and

the

corresponding

that

the

reactivity

complex

here,

more

mixture

of

two

of

since

equilibrating

3956

I-Trimethylsilyl-1:methoxyallene then

by

allylzinc

hydrolyzed

bromide

to give

the

OMe

1) n BuLi,

this

A

case,

protonation to a single

variety

metallation

of

of

allenes

by

mixture

yield

is

n-butyllithium

brought

to

in

reflux

and

THF',

for

12

h and

:

z)&ZnBr

-70°C

as

a

single

for

4) NH4CI,

60

by a favoured

carbons

1

functionalized

more

ethers.

isomer

on

H,O (MeOD)

and

3

almost

exclusively.

Deuterolysis

-4D.

and

or,

to propargylic

accounted

in 60%

-70°c

occurs isomer

simple

attention above,

_4

3) 12h, 65°C

SiMes

leads

large

sequentially the

3

-3

(MeOD)

treated before

-70°,

allylsilane

--.

Tn

is

at

is

simply, When

of

allenes

substituted

alkynes

are 2-4

easily

.

We

available

thus

turned

I-phenyldimethylsilyl-3-methoxyprop-l-yne

obtained.

chelation

lithio

of

This the

high

regio-

bismetallic

and

our

is treated

stereoselectivity

reagent

by

may

be

:

m l-OMe

1) 2) same as above

OMe PhMa,Sd

I+

3)

4)MeOD (or

I

z

m l--OMe

fi has been compared to both E and 2 5 to and is identical to the former. Following

the

metallatropic

course allenic

of

the

isomer

authentic

samples

By analogy,

metallation

of

2

of

we propose by

G.L.C.

the

product,

the shows

a

: OMe

PhMelSk--+

m

prepared

Z structure

PhMe2S*woMe m

mixture

according

for

4D. -

of

-5

and

its

3957

In

this

the

case, or

rearrangement, propargylic-allylic

Recently

et

showed

Molander’ an ether

that

function

The his

metallic

ketones

:

showed

al’,

in 83% yield,

can

internal

be

either

viewed

delivery

of

the

as

ally1

a

metalla-Claisen

moiety

of

the

mixed

:

reagent

Negishi

proceeded

carbometallation

alternatively,

that

although this

addition

much more

preferential

was located

reagents

at

ally1 than

Syn addition

the

display

of slowly

propargylic

the

same

zinc in

our

(85/15)

position

regio

bromide

to

case

(18-24

became

on the

selectivity

silylated

alkynes

h at

an anti

60”),

and

addition

when

:

substrate

when added

to

aldehydes

or

Me0 Me3Si

=

,OMe

1)

-70~

nBuLi,

Me3Si

2+ZnBr-70°C

R’ 3) 3.5 h, 35°C -7

5) Hz0

8

-8a R = Ph, R’ = H 55% ; -8b R = iPr, diastereoisomers is observed. Esters

can be reacted

or zinc

reagents,

the

keto-stage.

the

hemiketalate

4) RCHO or RCOR’

but

as well,

which

lead

R’ = H 55% ; -8c R = Ph, contrary

directly

We interpret

this

to

to the

fact

by the

the

bis

usual

R’ = Me 55%. A l/l

reactivity

allylic

carbinols,

interaction

of the

of

ratio

allylic

this

reaction

second metal,

of

lithium

-

stops

at

stabilizing

:

intermediate

Ph

P Zn

1)

2)

3)

as above

L

)

-Me3Si

4) PhCOOEt

NO

OEt

H20

)

55%

OMe

\ Imines

can also

be used

:

?Me 7

1)

2)

3)

r-l’

,

as above 45%

5)

H2O

b

Me3s(me

Me

3958

Metallated

allenes

can

activated

enynes

lithium3b,

followed

also

for

;

be

prepared

example,

by allylzinc

by

the

treatment bromide

gives

of

addition

alkyllithium

of

1-ethylthio-3-buten-I-yne

the

desired

reagents with

rearrangement

without

-

SEt

nBuI-1

+

THF

S-CH,--C”=C=C’

D )

‘L I

SEt

/+ZnBr

-6O"C,

:

\

-9

,

butyl

heating

SE1

-lOT, 15 mln --

to

56%

+5"C

2h

2) DzO In this

case,

a mixture

of

geometric

of purified

products

Although

yields

of these

reactions

before Work

is promising,

hydrolysis is

general

under scheme

way

:

and

isomers

presently

the

highly

are

good

candidates

for

in

this

direction,

as

the

nature

of

(Z/E

are

various

= 88/12) only

functionalized

further well

alkynes,

is formed.

modest*'

as

reactions, the

allenes,

the

high

regioselectivity

vinyl

zinc

reagents

particularly

delineation and

of

the

functionalized

at

hand

cyclisations. scope

of

allylic

this zinc

reagents.

References. lP. Knochel, J.F. Normant, Tetrahedron Lett. 27, 1039, 1043, 4427, 4431, (1986) 2 - a/ S. Hoff, L. Brandsma and J.F. Arens, Rec. Trav. Chim., Pays-Bas, z, 916 (1968) b/ J.C. Clinet and G. Linstrumelle, Tetrahedron Lett. 1137 (1978) c/ Y. Leroux, R. Mantione, Tetrahedron Lett. 2585 (1973). 3For general reviews on metallated allenes and alkynes : a/ L. Brandsma and H. Verkruijsse in "Preparative Polar organometallic chemistry", b/ L. Brandsma and H. Verkruiisse in "Svnthesis of Ed. Springer Verlaq (19873. c/ 'J.L. Moreau acetylenes, allenes, and cumulenes", Ed. Elsevier, Amsterdam*l981. in "The chemistry of ketenes, allenes and related.compounds", Ed. S. Patai, Wiley, New York 1980. d/ J. Klein in "The chemistrv of the carbon-carbon triole bond. R. Epsztein in “Comprehensive ‘carbanio; Ed. S. Patai, Wiley, New York 1978. e/ chemistry”, Ed. E. Buncel, T. Durst, Elsevier Amsterdam 1984 (Part B) 4Metallation of silylated alkynes : ref. 2, 3 and E.J. Corey, H.A. Kirst, Tetrahedron Lett. 5041 (1968) ; R.G. Daniels, L.A. Paquette, Tetrahedron Lett. 22, 1579, (1981) and references cited. 5J.G. Duboudin, B. Jousseaume, J. Organomet. Chem., 168, 1 (1979) 6E.I. Negishi, J.A. Miller, J. Amer. Chem. Sot., 105, 6761 (1983) 7G.A. Molander, J. Org. Chem., 48, 5411 (1983) 8In all these experiments, the raw product was obtained with yields in the 60-80% range and fair purity (according to NMR). Purification on silica dramatically diminished the yields for unknown reasons.

(Received

in

France

4 April

1989)