Insect antifeedants from parabenzoin trilobum (II) the absolute configuration of shiromodiol-diacetate

Tetrahedron

Letters

No.45,

pp.

INSECT THE

ANTIFEEDANTS

ABSOLUTE

Laboratory

(Beceived The

in Japan

structure

evidence').

1968.

FROM

Wada

University, 1968;

This

paper

presents

Nagoya,

Britain.

(II)

Faculty

of Agriculture,

Japan

received

publication

in IK for

has

evidence

TRILOSUM

in Great

Munakata

Chemistry,

of shiromodiol-diacetate

Printed

Press.

OF SHIROMODIOL-DIACETATE

and Katsura

of Pesticide

6 July

Pergamon

PARASENEOIN

CONFIGURATION

Kojiro

Nagoya

4677-4680,

been

which

derived

from

let us assign

6 August 19~) chemical

and

the absolute

spectroscopic

configuration

(I) for

shiromodiol-diacetate. Partial 131°C,

and

199°C

readily

1270

1.7(3H,

cm

alcohol

and

, nmr;

3440,

group

followed

no vinylic Both

Thus, Sa-hydrogen

That

bond

suggests

X-ray

established

that

these

6-monoacetate and

relative

The

treatment

with

boron

product

j=6.31

and

chromic

and

1240

2)

cm

-1

trifluoride

(VI, C17H2804,

l.O(3H,

j= 6.3)

d.,

3.9(1H,

.

These

product

gave

data

m.p.

C24H310,N

3500,

1.2(3H,

2.5 H-C-OH)

the nmr

H 0 7 m.p. 17 28 4

the monoacetate

181°C, kKBr max

by the

C

(IV),

etherate,

and

(VI),

the presence

is formed from

of III

the ketone

indicate

which

(III),

(CH3-CH-Cg3), 2.5,

dt.,j=lO,

is indicated

cyclization,

6-monoacetate

p-nitrobenzoate

trioxide-pyridine

V is a cyclized

and

that

analysis

epoxy

ring

germacrane

in I must

compounds (III)

have

having

group

in acidic

configuration

have

sesquiterpenes

the

as shown media

of I was

7)

trans-substituted

a-epoxy

3)

trans are

elephantin

of germacranolides,

4a-hydroxy

is stereospecific

The

1705

the

C

3430,

1720

s., 0-C-CH3), 5.1(lH,

s.,

H 0 , m.p. 17 26 4

of a tertiary

cleavage

spectrum

of the epoxy

of V, which

have

signal.

the double

recently,

of V with

mainly

1240

s., 0-CO-CH3),

by trans-annular

proton

consideration

d.,

2.0(3H,

1735,

in V.

On

gave

-1 . cm

to a cycllzed

O.Q(3H,

Oxidation

(II)

1730 and

-33.3.

(a)25 D

rearranged

-1

llQ°C,)ii;

which

3480,

s.,C=C-CH3),

H-C-OAc).

ring

shiromodiol

(a)z5 +36.4&t::

has m.p. (III)

acetylation.of

group

in the

would

structure

configuration

formed

from

, elephantopin epoxy give

ring

since

all-trans 7)

and

farnesol

and

heliangine8)have

and double

the cyclized

(Vl by

biogenetic

bond.

product

trans-annular

which

has

cyclization,

.

established

4677

by the detailed

analysis

of the nmr spectrum

4678

No.45

of v. boat the

The form

cycloheptene of the

structure

system

cyclohexane

(A) or

ring

4)

,

energetically

so that

the

favoured

relative

conformers

I.

Dihedral

5a+I6a

configuration

Angles

of Molecular

A

B

80'

120°

160°

O0

80°

80°

3o"

165O

Models

6a-H7a

H6a-H7/3

H

90° with

H-5

of models of H-5, The

H-8

on the

That

Thus,

shiromodiol

The

absolute

solution

1708 The

B,Y-unsaturated group

be shown

by the

the

and

coupling

and

constants

if the

the

(10,

cyclized

(H-6)

with

must

H-5

and

cyclohexene

of the

also

side

from

established

from

of the O-H bonded

nnr

coupling

65 or llO" 65 or llO" 30 or 150°

form

dihedral

-7 are

system

angles

near

zero.

in V has

chair

in VII of the

plane

in VII and

had

to possess

the

of about

An

inspection

form and

band

of the

ir. spectrum

VIII

group that

put

through

The

identities

1)

suggest

as

cm

-1

plane

all

put

in VII

ten-membered

that

VIII

indicates

cm

U.Y. also

shifted the

group Thus,

absorption has

the

ten-membered -1

with

methyl ring.

I.

carbontetrachloride

chelates

the vinyl

in Table

and

chromophore

through 1683

at C-9

configuration(I)

, which

of VII,

of the

shown

relative

of the dilute

at 3530

shows

methylene

of B,Y-unsaturated

region

the hydroxy

or the enanticmer. of H-4

of models

side

VIII

neighboured

inspection

hydroxy

and

to the

the

streching

10 the

that

2.5)

the ORD

on same

carbonyl

indicates

chromophor

2.5 and

product

hydroxy!. group

on same

structure(C)

group

of H-6

is clear

intramolecularly

maximum

present

only

ir. spectrum

ketone

acetoxy

couplings

couplings

of I was

This

coupling

on a-position.

three

carbonyl

cm -' in VII15).

the

on a-position

The

absorption

carbonyl

and

.

has an

of the

The

ring.

1)

of VII

existence

shows

configuration VIII

from

Ht3-H9

the

is possible

diacetate

(V) reSpeCtiVely.

bearing

both

placed

is placed

and

in VII and

this

-7 are

H-7.

carbon

nmr

90°

H7-H8

H8/3-H9(3

since

that

signal

H-8

165O

H8~-H7a

3o"

and H-7

-6 and

H -H 6 7

H8-H9

shows

as

90°

5a-H6

SO0

8a-HQa

proton

be depicted

B

from

Required

7o"

8a-H7a

H8a-H9@ Tpe

and

. .

A H

to chair

of V could

A and

Required

H H5a-H6,3 H

analogous

(B). TABLE

H

has two

same

to

carbonyl.

and

the

VII would maxima

conformation

4679

No.45

(A)

1 B)

I .

Rl=Rz=Ac

V.

II .

RPRPH

VI.

Ill.

RI = AC , R2 = H

IV.

RI = AC, R2 = COC6kh-NO2

RlH,P-OH R=O

VII. VIII.

R=H R = AC

No.45

4680

with that of VII.

VII and VIII show a negative Cotton effect 6, ((b‘1326-24200,

a: 514, MeOH) and ( <4‘1326-42500,C4;12Q0+38300, The high a-values inherently absolute

dissymmetric

conformation(C)

respectively.

reveals that in VII and VIII the fi,Y-unsaturated ketone chromophor

6)

.

-148 -lOS= -256) indicates

since the

the s-configuration

Application

of benzoate

negative A CM1value at C-8.

forms an

to have the

rule for the hydroxy group

(
alcohol=

Thus, shiranodiol

diacetate

was assigned

configuration(I).

Footnotes

and References and K. Munakata,

Tetrahedron

1)

Part I. K. Wada, Y. Enanoto, K. Matsui, this issue.

21

T. R. Govindachari,

3)

V. Prelog and V. Kiing, Helv. Chim. Acta, 39, 1394 (1956). -

41

R. Pauncz and D. Ginsberg,

Tetrahedron,

5)

These are the wave numbers VII and VIII.

in the ir. spectra of the chloroform

6)

A. Moscowitz, 1945 (1962).

7)

S. M. Kupchan, Y. Aynehchi, J. M. Cassady, A. T. Mcphail, and A. L. Burlingame, J. Am Chem. Sot., 88, 3674 (1966). -

81

M. Nishikawa, K. Kamiya, A. Takabatake, 22, 3601 (1966).

-

grouping

From these data, VII and VIII were concluded

and (D) respectively.

of III supports the above conclusion

to the absolute

a: 808 MeOH)

cb>280+27200,

B. S. Joshi and V. N. Kamat,

Tetrahedron

Letters,

2l, 1509 (1965).

9, 40 (19601.

K. Mislow, M. A. W. Glass and C. Djerassi,

solutions

of

J. Am. Chem. Sot.,

84,

G. A. Sim, H. K. Schnoes,

H. Oshio, Y. Tomie and I. Nitta, Tetrahedron,