The determination of the absolute configurations of some phenylallenecarboxylic acids

The determination of the absolute configurations of some phenylallenecarboxylic acids

TetrahedronLettersNo.44, PP. 4371-4374,1967. PergamenPress Ltd. Printed in Great Britain. OF TRE DETERMINATION THE ABSOLUTE SOME PHENYLALLENBCARBO...

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TetrahedronLettersNo.44, PP. 4371-4374,1967. PergamenPress Ltd. Printed in Great Britain.

OF

TRE DETERMINATION

THE ABSOLUTE

SOME PHENYLALLENBCARBOXYLIC Keiji Shingu, Sanji Hagishita Department

of Chemistry,

OF

CONFIGURATIONS ACIDS

and Masacumi Nakagawa

Faculty of Science, Osaka University,

Toyonaka,

Osaka, Japan

(Receivedin Japan 24 July 1967) We wish to report the synthesis , resolution absolute

configurations

and the determination

of some phenylallenecarboxylio

PhYc=C=CRCOoli

arids

of the

(I).

(I, R=H, He, Et, &-Pr and &-&a)

R’ Phenylallenecarboxylic procedure

acid (I, R=H) was prepared

(l), and the other acids

the method outlined

PhsP=CHCOOEt

OK

(I, R=Me, Et and A-Pr) were synthesised

PhaP= -COOEt r: O=C- H-Ph '5(

=C=CBCOOH

Phenyl-i-butylallenecarboxylic

pyrolysis

(2)

SOCls (3)

Ph,

CH-Cxe-COOW

.

(I, R=Me, Et and &-Pr)

too, could be obtained by

route was found to be more convenient.

Ph,

- =C=c!HCl j_-Bu/c

1) Mg

e

isomers were obtained excepting

(I, R=&-Bu)*

2) coa

These racemic acids were resolved via the cinchonidine

salts. 'lhe (+)-

the case of R=Et which gave the (-)-enantiomer.

* lhe attempt to prepare the optically chloroallene

.

R’

acid (I, R=s-Bu),

the same reactions, but the following

&-B/OH

by

Phi c

-c-CSCB

to the known

in the folowing chart.

p>Hcocl

Ph\

according

active acid starting from the active

failed due to the complete

racemisation.

4371

4372

N#d#

All attempts

of resolution by the use of other bases such as brucine,

strychinine,

quinine and cinchonine gave unsatisfactory

points and the optical rotations

(in methanol)

results. The melting

of these acids are summarized

in Table I. TABLE I Physical Properties R

w

m.pt

109-110

These

Me

allenic acids

structures

Acids

(I)

&-Pr

&-BIJ

88;5-89.5

96-98

+318

125

+205

-280

+177

(I), on treatment with 1 mole of bromine

chloride, gave neutral materials The elemental analyses,

Et

101-102

+42o

[aID

of Phenylallenecarboxylic

I.&-

in carbon tetra-

(70-908 yield) with loss of hydrogen

bromide.

and N.M.R. spectra indicated their bromolactone

(11). Br+.

: R\ ph,cic=c<~-oH

-

Br2

p;>$:y

b,,GOH

I.

R

C-&H

Ph :

I

(1)

(11)

(IIE) The optically active allenic acids crotonolactones

(I) resulted in the optically active

(II). Their properties

are listed in Table II. The rotations

TABLE11 Physical Properties R

H

m.p.

88.5-89.5

99-101

+149*

+118

Cain

Me

Asterisk

were determined

of Crotonolactones Et 61-62 -190

(II)

i-Pr oil +260

t-Bu 65-66 +64

indicates the value in z-hexane.

in methanol

unless otherwise

indicated. As illustrated

in the

No.44

4373

reaction scheme, the stereospecific the carboxyl group participation mechanism

is considered

unsaturated

acids

cyclisation

assuming

in the attack of bromine cation. The proposed

to be analogous

(4). The structures

following degradation.

Permanganate

successive hydrolysis

in an alkaline

hydrory acids

may be rationalised

to that of the bromination

of some y,b-

of II were also confirmed by the

oxidation

of II in acetone-water,

and

solution resulted in the corresponding

(III, 40% yield). Moreover,

all the hydroxy

acids

(III) were

TABLE III Physical Properties R

H

m.p.

130.0-131.5

Me

[a]R obs. +151 [a]=

lit. +149.7

of Hydroxy Acids

(III)

A-Pr

Et

115-116

126-128

+36.'5

-32

&-Bu 110-112

108-109

-5o*

+33*

(5a)

. Asterisks

indicate the values in methanol.

obtained in optically active state , when the active crotonolactones used. The melting points and the. rotations (III) together with t.re literature optical purity of the resulting of the brominative

cyclisatien

(in ethanol) of the active acids

values were listed in Table III. The high

III indicates

the highly

reaction. The hydrolysis

has already been shown to proceed with retention hydroxy acids

assigned compounds

to II and I (WE,

stereospecific

in these

of III (R=H, Me and Et) are

the absolute configurations

of S(+) can be

Me and Et). The fact that the intermediate

cyclic

(II) can be isolated in optically pure state in the conversion

allenic compounds

(molecular dissymmetry)

(III) of known absolute configurations configurations

into the asymmetric

makes unambiguous

and &-Bu) have not been reported yet , the configurations Recently,

studied the O.R.D. of the derivatived

of

carbon compounds

our assignment

of PI-and I. As the optical active hydroxy

their optical rotatory properties.

nature

of ester intermediate

of configuration

(6)s and the absolute configurations

shown to be S(+) (7). Therefore,

(II) were

acids

of the

(III, R=A-Pr

were determined

by

Klyne and the co-workers have

of mandelic

acids

(8). They have attri-

4374

No.44

buted the

the

n--_*n*

related

to

Cotton-effect

of

transition

of the

the

positive

Cotton-effects AE

6,

noted 220

of

that

III

rnp region

Brewster's Thus,

all

(I) are ration

of

The acids

which

indicating

the

hydroxy

to have

the

and

and

group,

in the

and

C.D.

region

as

We have

negative

limited

maxima,

III

224 Me

(R=H,

[o]D

validity

220-230

rnp region

(S)-configurations

Cotton-effects.

4-B":

has

Et)

mp

and

exhibits

of

simple

from

the

to

have

been

observed

the

(+)-

i0E12.5

and

222

Et).

mp

It is to be

(+)-Cotton-effect application

of

at the

(9).

the

shown

the

same

(R=t-Bu)

rule

of

(R=i-Pr

in the

(R=H , Me

carboxyl

sign

III

respectively)

III

acids

(III)

derived

(S)-configuration

(+)-allenic

acids

studies

on

the

optical

(I) will

be

reported

and

(I) are

rotatory

in near

(+)-phenylallenic

accordingly

established

the

to be

properties

of

the

absolute

acids configu-

(S). phenylallenecarboxylic

future.

References M.

1.

G. H. Mansfield

and

2.

G. Markl,

Ber.,

3.

Y.

R. Bhatia,

R. J.

4.

D.

Evans,

70,

Ber.,

A. McKenzie

7.

a)

4061

and

Ind.,

9.

T.

R.

and

S. R.

and

Biochem.

and

Sot.,

59, =

Z.,

1016

2,

SOC.,

Landor,

J.

1956, -

Chem.

R. Taylor-Smith,

Campos

; P. N. Craig,

Chem.

and

K. Mislow,

z,

Moura

Chem.

4761.

K. L.

Lindsay,

J. Am.

&

129 (1952).

444

(1914);

b) A.

c)

and

and

A.

24

i

1506.

Chem.

HcKeneie

A. McKeneie

1959, -

1963,

ibid.,

ibid.,

(1910);

SOC.,

G.

SOC.,

W.

Ritchie,

23 (1937).

6.

-

de

J.

(1961).

3009

D. Landor

M.

a) II. Horsters, J.

a,

Whiting,

S. R. Landor

(1953)

1044

Clough,

a.

P.

R. T. Arnold,

2, 5.

Chem.

C.

J. Am.

(1956);

c)

1964, -

233.

Emerson,

L. H.

Roach

and

J. H.

Breluster,

D. R.

-Ber.,

S. Lesslie,

M.

Chem.

Sot.,

S. Mitsui,

F. Ewing, J.

J. Am.

Swan, Chem.

(1951);

Imaizumi,

W.

Klyne,

J.

Chem.

Sot.,

153 (1928).

3954

2,

S.

61,

Y.

b)

Senda

D. G. Nelson, Sot.,

81,

5475

1965,

J. H. and

D. A.

4007.

(1959).

Brewster,

K.

Konno,

V. Peters,

ibid., Chem.

;