Asymmetric palladium-assisted alkylation of olefins

Tetrahedron Letters,Vol.23,No.9,pp Printed in Great Brltaln

0040-4039/82/090939-04$03.00/O 01982 Pergamon Press Ltd.

939-942,1982

ASYMMETRIC PALLADIUM-ASSISTEDALEYLATION OF OLEFINS

A. SolladrC-Cavallo+and J.L. Haesslein Laboratoire de Chlmre Organrque de 1'Ecole Nationale Sup6rieure de Chlnne, (ERA no 687) Dniversrt~ LOUIS Pasteur, 67008 Strasbourg, France Jan-E. B&kvall Department of Organic Chemistry, Royal Institute of Technology S-100 44 Stockholm, Sweden

Palladrum-promotedalkylatron of some alkenes using choral sulfoxideS-rY contalnmg carbanlon as nucleophlles or using optrcally active N,N-dlmethyl-u-phenylethylamlneas ligand together with a non-choral stabilized carbanlon as nucleophlle results in an asymmetric Induction of 10-40X.

Palladlunrasslstednucleophllic addrtlons to olefrns are well known and of particular Interest in organic synthesis.192 During work on transition-metalasslsted asymmetric 3 synthesis we became Interested in the posslblllty of inducing asymmetry in the nucleophrlrc addition of stabilrsed carbanlons to n-oleflnpalladlumcomplexes. Asymmetric induction has previously been observed in the palladium-catalyzedcycllzatlon of 2-allylphenol4 and rn the nucleophilic addition of stablllzed carbanron to r-allylpalladlum 5 complexes. In the preceeding communication we have shown that an asymmetric induction was obtained 6 in the palladium-promotedoxyamlnatlon of oleflns. We now report some results from palladrum-promoted asymmetrrc alkylatron of oleflns. The general accepted route for palladium-assistedalkylation is shown m

Scheme

Scheme 1.

1.

I?,

R'

.,I 2

n)

1

PdC&rRCN],

L

NEt,

R’i+-p::Ni

R2

R,

'R2 dl

R’

939

25

x

:?'

R’hlet --__)

R1

x

Y

8' 32 R2

ait 22 R2

i?!?

940

Reductive u-complexes

cleavage

(by H2 or NaBH4) of

-2a and -2b gives

the products

and R are not H, the final 2 chlrallty may be Introduced choral

nucleophlle

products by the

this

work we have the

lnvestlgated

we have

Naphthyl)

used

ethylamine

first

pure

llgand

In the

palladium

an asymmetric

IntermedIate

black.

When R1

carbon. In these reactlons, 4-6 by the use of a 6 a choral nucleophile . In

on the metal,

together

5 (racemlc)

(-1s

bond

with

llgand

two approaches

carbanlons

optically

a choral

a choral

the

sulfoxlde-containing

llgands,

-3a and -3b bear use of

or by the use of

used

the palladium-carbon

-3a and -3b together

wrth

As choral

nucleophiles, 7 pure). As

or 2 (optically

N,N-dlmethyl-a-phenylethylamlne

5,

we have choral

and (+)

a-(1-

1.

* EO-CH,

plol-SO-FH-COOtBu

LI

LI 4

The results 1,2

and 4,

ratios

of

the the

from

not

In entry

ester

,

5 the purity

of

methyl

of

induction

products,

1s determined

and the

be determined

optlcal

6

a)

alkylation

asymmetric

mixtures

The regloselectlvlty (compounds

asymmetric

amount of crude

+

+ &),

too

b).

are

+ 9b)

ratios

on the

Table

from

the

using

between

the

purity

methyl crude

in

and lo,

The optlcal

many triplet-like

1s determined

given

1s determined (9a --

from

(compounds

of

regloselectlvlty

obtalned

(8a -

simultaneously

doublets

by NMR because

some olefins

mixture

-lla

diastereomerlc 1 250 MHz H NMR

methyl-triplets

of

signals

1. In entries

compound -8a could

In the + 2,

spectrum.

but

the

of -llb

-llc followed 7 and 9 were

was IndIrectly determined by desulfurizatlon (Raney Ni/etOH) to the 1 by 90 MHz H NMR analysrs using Eu(hfc) 3. The esters obtained from entries analysed

using

Eu(hfcj3

and 90 MHz ‘H NMR.

“P? NH*

OOtBu

CH,

A few features runs

5,

and 7

ned

In entrles

very

similar

asymmetric obtalned that

should

be noted.

may be related 1 and 2 (20

to

methyl-p-tolyl lnductlon

during

In those

tions

are,

rapid

enough

entrles

compared

sulfoxlde

of (1 to

klnetlc to

The lnverslon

the

the

“size”

40%) are

obtained

addition

therefore,

to

of

larger to

5)

same anlon the

reactive

resolutions, rate

of

than

regloselectlvlty

anion those

aldehydes

in run 5 (20%) the

of the

obtained

(OX in

1s poor

the

compared

to benzaldehyde r-complexes unless

nucleophllic

the

case to

(91X).* are

choral

exchange

addition

between

The asymmetric during of the It

addition

obtalof

benzaldehydea asymmetric

the

(Curtin-Hammet

the But the

induction

must be pointed

and racemlc.

between

run 2 and

lnductlons

out

The reac-

enantiomers principle).

1s

941

Table

Runs

1

Asymmetric

Palladium-asslsted

Nucleophlle R"

Olefms

alkylatlon

of oleflns

Rat10

Products

Llgand

a/b %

Asymmetric mductlon %

30

NEt3

40 20

NEt3 5

NEt3

I

NEt3

z

-R’*

20

20

NaCH[CO, Et&

F,

& -R’

a ,2

ho

b

4~\

-

a NaCH[CO,Ct]2

6 b

37

‘A

F!aCH[CO$t:2

6

IIaCH:CO,Lt!2

;‘nCH:CO,,

a

R1*-- CH :OPh 2

,

R2* = CB(&h)C02tBu

‘I2

, R3 = CRK02Et)2

14 -

63

32

942

When the chlrallty metric

InductIon

butene).

1s introduced

depends

It must be polnted

dlastereomerlc provided

of the olefln

the asymmetric

mixtures,

induction

for nucleophlllc

procedure

was allowed

to Increase

through

THF

The chemical

Attempts

to increase

thus far obtained

the asymmetrlc

The product

K

J.E. Backvall,

K

(c) J.E. Backvall

and E.E

2. L S

Hegedus,

(1980)

R.E

Sloberg

(1980);

5

6

(b) A

T. Hosokawa,

J

optical

personal

communlcatlon

Strege, J

Am

J E. Backvall,

Bjorkman,

S.E

C

communlcatlon

Mloskowskl

Tsamo, J and A

on certain

J. Am

Sot

,

in

Angew

1363 (1974),

Chem Sot , 102, 4973

Chem. Int. Ed., 2,

OrganometaZ Chem

Sonoda, JCS Chem 4-substituted

1005

172, 165 (1979).

Comm

687 (1978), Recently

2-allylphenols,

T. Hosokawa

Chem Sot , 95, 8201 (1973) Chem. Sac , 99, 8201 (1973) Bystrom

and A. Solladl&Cavallo,

Tetrahedron,36_,227 (1980).

Kahn and A

Mltra, J, Org. &em., 43, 2923

France

Novelrb er 1981)

20

J.E. Backvall,

102, 4980 (1980).

in this issue.

and G. SolladlB,

Still, M

(Fecelved

Hayashi,

Am. Chem

and

2893 (1980)

Syntheszs, 1, 185 (1981)

8. G. SolladlB, 9. W.C

and T J

Akermark,

Chem, 2,

Org

J.L. Haessleln,

Am

B.M. Trost and P.E E.R

d

and E

J

amine as

K. Sllrala-Hansen

(b) B

S I. Murahashl

Dietsche,

Zetterberg,

K

Tetrahedron Lett

Suffert,

B M. Trost and T J

by using a "more dlsymmetrlc"

127 (1974),

Darlington,

yield was obtained

1) are encouraging.

Zetterberg,

M.A. McGulre

SolladlE-Cavallo S. Miyagl,

a higher

preceding 7

and K

and W.H

,

AND NOTES

Hegedus,

Bjorkman,

Wllllams,

L.S. Hegedus

3. (a) A. SolladlE-Cavallo,

4

L S

J. Orgunomet. &em., 2,

Sloberg,

K. Siirala-Hansen,

20 and 35%

are under investigation

REFERENCES

(a) B. xkermark,

for 2 hrs at -5O'C,

mixture -3a + 3b was

and are still low fbetween

(Table

induction

llgand together with choral nucleophlle

1

The

and analyzed.

chromatography'

lnductlons

of 10 mln

(6 mmol) was added dropwlse

the mixture was stirred

yields have not yet been optimized

but the asymmetric

ratio,

The mixture was then cooled

a syringe over a period

the flask was flushed with H2 and the cold bath removed isolated by column

are

4 nun01 of PdC12(C6H5a)2

to -5O'C and the carbanlon

of 10 min. After

over a period

the n-complexes

10 min at 0°C (runs 2, 3, 4, 5, 7, 8, 9) or 10 mln

to -78'C, 8 mm01 of amine was added dropwlse

through a syringe

that asym-

are the same for the two Isomers

has been used for the alkylatlons

and 8 mm01 of the olefln were stirred

lt appears

will depend upon the dlastereomerlc

addltlon

at 20°C (runs 1 and 6) under argon In 40 ml of anhydrous

temperature

llgand,

(30% for 1-hexene, 0% for truns-2-

(runs 6,7, 9) where

out that In those cases

the rate constants

The following

by the way of a choral

upon the nature

(1978)

Tetrahedron Lett ,