Synthesis of axially dissymmetric 3,5-octadiene framework with C2 chirality via palladium(II)-catalyzed twofold [3,3]sigmatropic rearrangement

Tetrahedron Printed in

Letters,Vol.29,No.lO,pp Great Britain

1157-1160,1988

0040-4039/88 $3.00 Pergamon Press plc

+ .OO

SYNTHESIS OF AXIALLY DISSYh4METRIC3,S-OCTADIENE FRAMEWORK WITH C2 CHIRALlTY VL4 PALLADIUM(I&CATALYZED TWOFOLD [3,3)SIGMATROPIC REARRANGEMENT Seiki Saito,*

Shin-ichi

Hamano,

Department

University,

Tsushima,

Palladium(II)-catalyzed

(bisbenzyloxyl-2(E),6(g)-octadiene

[3,3]sigmatropic has proceeded

(bisbenzyloxyl-3@),5(g)-octadiene, termini,

which

constitutes

Asymmetric optically reasonable creating

translating

a novel

Diels-Alder

active

strategy

auxiliary

must be singly

chiral

centers

tagged

700

of (4R,5R)-4,5-(bisacetoxy)-1,8-

chirality

completely

to the migration

pure 3,5-octadiene

with C2 chirality.

and versatile

multiple

in dienes

seems

Moriwake*

to give (2S,7S)-2,7-(bisacetoxy)-1,8-

efficient

containing

by this method

Japan

rearrangement

of optically

and Toshio

of Engineering

Okayama,

convergently

is the most

ring systems

Keiji Okada, Faculty

the original

synthesis

cyclohexane

new chiral

Moriyama,

Chemistry,

Okayama Summary:

Hiroshi

of Applied

chiral

entry

centers.

or dienophiles,

to be highly

for the synthesis For performing

or both of them.

challenging,

a progress

of

it, a Though

in the breadth

of cycloaddition processes and the level of efficiency in this context have extremely been encour11 aging. Embarking on this field, we have contemplated to explore a novel asymmetric Diels-Alder system

which

features

and, consequently,

dienes

multigram

quantity

relying

on palladium(B)-catalyzed system

task to be achieved

4,5-(bishydroxyl-2,6-octadiene we planned

can be elaborated

through

acid diester

selection

the solvent,

(2) which

with DIBAL-H.

of at least

in which

a simultaneous simultaneous

four factors,

not methyl

After

or ethyl

twofold

L-tartaric

E-geometry

for both olefinic

linkages

hydroxyl

endeavors protecting

must be satisfied.

but isopropyl, 1157

formyl

groups

acid into is established.

functionalities

in appropriately

toward group,

we

acid.

for transforming

ester

A primary

and in a 2) of rearrangement

L-tartaric

of two terminal

as well,

pure form

methodology

long-standing

reagent,

into account.

faces

In this communication

[3.3]sigmatropic from

of homotopic

i.e., the

homotopic

of 1 in an optically

condensation

reduction

and the kind of condensation

or MEM but acetonide,

and, thereby, can be taken

is attainable

is to devise

backbone

For this purpose

that

of dienophiles

of the goal, i.e., synthesis

4,5-(bisacetoxyl-2,6-octadiene

L-tartaric

auxiliaries

supply of such novel dienes.

be a replenishing

the realization

The first

two chiral

only endo or exo-approach

goal of this idea should will disclose

possessing

which protected

this end we have found

the alkyl group of tartrate,

Eventually,

not MOM, TBDMS,

not THF, CH2C12, or ether

but toluene-

1158

hexane

system,

promising

and not Ph3P=CHCOOEt

but (i-PrO),P(O)CH,COOEt,

In the event

diisopropyl

L-DIPT

was reduced

solution

of ethyl

condensation

with DIBAL-H

to diethyl

by the addition

For successful the reaction

otherwise

appropriately. and/or

This situation

intermediary

by 13C-NMR revealed eight-carbon

benzyl

signals,

reduced ethers

and the product

execution

to be

analysis

that

4 keeps

2 hours

(7) in 70% yield

and olefinic

even

i.e.,

purified

protecting factors

two equiva-

other.

groups

off as usual, from 4 after

spectroscopies

geometries

if other

centers,

hydroxyl

group was splitted

of 7 by ‘H- and I3 C-NMR

chiralities

the acetonide

mixture

the reaction

to diol (5)4) and thus-generated

the acetonide

at -78” to 0”.

Diagnosis

of 4

dissymmetric C2 chirality by indicating carbons. 3) Then, the two ester groups

of existing

absolutely

were

giving silica

has clarified

has been

a

the

was chromatographically

must be anti to each

axially

temperature,

into the cold reaction,

of this transformation

means

available

(4) in 78% yield. 3) :

a deteriorated

functionalities,

that

half of the real number

with DIBAL-H

including

of water

affording

1,2-(bisbenzyloxy)-2(B),G(E)-octadien-4,5-diol framework

at -78” and, at the same

0.5 hour at -78” and additional

probably

formyl

unequivocally

(6), in which,

Stereochemical

system

(4R,5R)-4,5-0-isopropylidene-2(E),6(B)-octadiendioate

[crg7 -70.1” (c 2.4, CHC13).

4 were

have proven

from commercially

in THF was introduced

during

group is essential, lent ester

(3) prepared

in toluene-hexane

being continued

was quenched

to give rise

L-2,3-0-isopropylidenetartrate

sodiodiisopropylphosphonoacetate

reaction

The reaction

are set

respectively,

and reproducible.

protected

only of as

rise to (4R,5R)5)

gel chromatography. again

that

preserved

an essential

throughout

the

transformations.

b

0 78%

L-DIPT

3

OzEt

c, d, e

)

70%

4

7

a) 2,2-dimethoxypropane

(1.1 eq)/p-TsOH/refl.: b) i. DIBAL-H (P.aeq)/PhCHJhexane (1:1)/-78°C, 4 h. Ii. (i-PrO)zP(O)CH(Na)COOEt (5.0 #q)/THF/-78-C, 0.5 h and -78”C-O”C, 2 h; c) DIBAL-H(2.2 eq)/THF/-78Y, 3 h and -78’C-O’C, 2 h: d) BnBr(2.2 eqVNaH(2.2 eq)/DMF/rt, 3 h; e) ZN-HCl(1.5 eq)/MeOHBO”C, 6 h.

As quickly ment

system

recognized

is seemingly

located

at C(4) and C(5).

related

variations

way under

were

the standard

from

the structural

feature

able to be introduced It turned

extremely conditions.

out, however,

of 7, two set of [3,3]sigmatropic

by simply that

functionalizing

the Claisen

the two hydroxyl

rearrangement

rearrangegroups

and available

a formidable challenge, none of these taking place in the desired 6) To our delight, however, we have been rewarded by the method

1159

for equilibrating

allylic

7 was acetylated catalyst

(10

esters

as usual

mol%

which

to 4,5-(bisacetoxy)-2,6-diene

in THF at room temperature

(bisacetoxy)-3(B),5(B)-octadiene ‘H-NMR

(c 1.35, CHC13); C(1,8)H2),

12&4(d),

(m,

10H);

supported

that

Moreover,

in order

137.8(s),

carbon-chain

was transformed

(8), which,

after

Hz, Jvic=6.4Hz,

silica

on exposure

gave

to establish

C(1,8)H2),

(2S,7%l&(bisbenzyloxy)-2,7(u$

additionally,

through

unequivocally acetonide

4.52 (d, 2H, Jgen=12.2

71.19(t),

72.60(d),

the absolute

stereochemistry

(10) through

reasonable

that

around

appeared

127.7(d),

as 9.

C(2) and C(7), 9

pathways,

as shown below.

antipode

that

diethyl

the same in magnitude with opposite L-tartrate, 7) which led to the confirmation

127.6(d),

for 9 has strongly

C(1) to C(8) should be strictly

derivative

6.24 (m, 2H, =CH-

73.20(t),

a COSY experiment

HZ,

HZ, BnOCH),

sign as that

from

-41.0’

5.68 (m, 2H, =CH-C(OAc)),

126 MHz) 6 21.19(q),

170.2(s):

arrangement

into glycerol

derived

Thus,

to RdC12(CH3CN)2

The (ajn value of 10 was essentially

ration

2)

of acetonitrile.

gel chromatography:

5.48 (m, 2H, AcOCH),

13C-NMR (CDC13,

132.4(d),

complex

(CDC13, 500 MHz) 6 2.07 (s, 6H), 3.52 (dd, 2H, &em=10.6 Hz, Jvic=4.5

3.55 (dd, 2H, Jgen=10.6

129.4(d),

chloride

for 4 hours),

(9) in 82% yield

4.55 (d, 2H, &II= 12.2 Hz, BnOCH), C=), 7.30

uses the palladium(h)

of an authentic

the absolute

configu-

of 9 is (2S,7S).

b 7

2

Bn

Bn

n-

5 OAc

6Ac 9

8

g

22

WC BnO&H

>

B-H

p

L

BnO 10

(ax3 +20.2“ (c 2.56, CHCls) a) Ac2 (2.4 eq)/DMAP (2.6 eq)/CHzClz/rt, 4 hr; c) WMeOH/-78“C. then (CH3)2S; f) dimethoxypropane/acetone/H+

Another

possible

was not detected

conjugated

at all which

diene-diol

(10 mol%)/THF/rt, 3hr; b) PdClz(CH3CN)z d) NaBH&eOH; e) LiAIHd/THF/-50’C;

structure

is to be formed

through

such as 2,3-(bisacetoxy)-4,6-diene a stepwise

mechanism

involving

framework

(12)

an intermediary

1160

2,5-(bisacetoxy)-3,6-diene rearrangement involved still

of 8 has proceeded

simultaneously

holding

C2 symmetry

as a whole

translation

of the original stereochemistry.

TA seems

other

of stabilizing

conjugated

chiral-building of which

to constitute

of the present diene

Diels-Alder blocks

should be responsible them

rearrangement

for the complete

termini

with clean investigation

whereas,

anti-periplanar

of the corresponding

should

conformation

interactions,

m-bonds, are

the energy

being

chair

is open for further

of non-bonded

the conjugated

moieties

as a double

relationship

transition

be a consequence

in TB,

state.

of the formation

functionality. reactions

utilizing

with C8 backbone

will be reported

above

between

than lb in terms

must play a role in lowering

irreversibility

Asymmetric

final choice

[3,3]sigmatropic

both allylic-acetate

is indicated

at C(4) and C(5) to the migration

A reasonable

The apparent

manner,

which

(TA or TB) and, thus,

C-O chiralities

bonds destined which

the palladium(II)-catalyzed

concerted

state

to be more probable

the two o-(C-C) to each

in highly

in the transition

suprafacial because

(11).8) Consequently,

system

thus-obtained

presented

diene

and synthetic

in this work are currently

applications

our major

of

concern,

details

in due course.

Acknowledgments: We are grateful lH (500 MHz)- and 13C (126 MHz)-NMR

to The SC-NMR

Laboratory

of Okayama

University

for

experiments. References and Notes

1) L. A. Paquette

in 'AsymmetricSynthesis",J. D. Morrison,

Ed., Academic

Press,

New York,

1984,

Vol. 3, pp 455-501. Am. Chem. Sot., 94, 5200 (1972);

2) a) P. M. Henry, J.

Engl., 23, 579 (1984) and references question

of chirality

Bongers,

and H. Tanaka,

3) 4: 13C-NMR 142.0(d),

transfer

cited

by means

J.

therein;

b) L. E. Overmann, for the first

of this strategy,

Angew Chem. Int. Ed.

report

which

see P. A. Grieco,

addressed

T. Takigawa,

the S. L.

Am. Chem. Sot., 80, 102 (1980).

(CDC13, 25 MHz) 6 14.23(q), 26.85(q),

60.63(t),

79.88(d),

110.8(s),

123.8(d),

(CDC13, 100 MHz) d 1.30 (t, 6H), 1.48 (s, 6H), 4.20 (q, 4H), 4.25 (m,

165.6(s); ‘H-NMR

2H), 6.12 (dd, 2H, J=16 Hz, 1.5 Hz), 6.82 (m, 2H). 4) 5: [og7 +17.2” (c 1.0, CHCIJ); ‘H-NMR (m, 6H), 5.70-6.25 5) 7: [a];’

-20.5” (c 2.0, CHC13); IH-NMR

PhCHZ), 7.28-7.37 127.71(d),

5.77 (ddd, 2H, 5=15.6, 128.4(d),

7) The antipode

129.6(d), Claisen

silylketene

decomposition synthesized

(CDCI,,

500 MHz) 6 4.02 (m, 6H, CHC=CCH2),

4.3, 1.3 Hz, =CH-C(OH)),

5.91 (dt, 2H, 5=15.6,

(m, 10H); 13C-NMR (CDC13, 126 MHz) 6 69.89(t),

6) We have executed Ireland’s

(CDC13, 60 MHz) 6 1.45 (s, 6H), 2.30 (d, 2H), 4.05-4.30

(m, 4H).

131.28(d),

has been obtained as reported

Johnson’s

[bisacetylation/LiHMDS/Me3SiCl]

of the substrate

74.86(d),

5.4 Hz, BnOC-CH=), 127.63(d),

138.0(s).

[CH2=CH-O-Et/Hg(OAc)2/A],

acetal

72.24(t),

4.50 (s, 4H,

or in the formation through

benzylation

(A. H. A.-Hakim,

ortho

ester

rearrangements

of multi-component

IMeC(OEt),/H+/Al, for 7 to result

mixtures.

of (RI-l,2-0-isopropylideneglycerol

A. H. Haines,

and

in the

and C. Morley, Synthesis,

which

was

1985, 207):

Lug7 -21.2” (c 4.33, CHC13). 8) For the pertinent

system,

see A. C. Oehlschlarger,

791 (1983) and B. T. Golding,

C. Pierpoint,

(1981). (Received

in

Japan

24 November

P. Mishra,

and R. Aneja,

1987)

J.

and S. Dhami, Can. J.

Chem., 62,

Chem. Sot. Chem. Commun., 1030