Cycloadditions of organic azides to cyclopentadienones

Tetrahedron Letters No. 29, pp 2463 - 2466, 1977. Pergemon Press. Printed in Great Britain.

CYCLOADDITIONS OF ORGANIC Alfred

Hassner,

David

AZIDES

J. Anderson

Department State

TO CYCLOPENTADIENONES1a

University

and Robert

of New York

Binghamton,

H. Reuss

of Chemistry

lb

at Binghamton

New York

13901

(Received in USA 5 Mqy 1977; received in UK for publication 8 June 1977) Organic not only

azides,

cycloadditions. for

in particular,

as precursors 2

the thermal

cycloaddition

of j_ via the azide with 2_ acting

azides

have

been

which

shown

add

We now report with

2 which

group,

the thermal

affords

that can a priori

the vinyl

thermally

in a Diels-Alder novel

with

fashion

nitrene

be predicted or the olefinic Some vinyl

2 via prior

transformation azepines 5. 3

of several

types

of organic

such as azabicycloB.3.OJoctanes,

azabicyclofi.l.O]hexanones,

and pyridones,

interest

in dipolar 2 includes

moiety

component.

to produce

cycloaddition

heterocycles

recent

partners

1 to cyclopentadienones

as the 2r- or 4a-electron

to react

bicyclop.2.1]octanones, C2.2.l]heptanones

azides

have elicited

as potential

of pathways

of vinyl

bond

azides,

but also

The multiplicity addition

double azirines

vinyl

to nitrenes

depending

as well

on the structure

to azides aza-

as azidobicyclo of the azide

sub-

strate.4 For instance, produce 1767 la -

2 (52%)

cm-l),

vinyl

together

An 88% yield

azide with

of 3a was

(1.5 eq) and 2b to stand

la_,

X:

H

lb, X: NO2 i; __)

2b in refluxing chloroform to -la reacts with a minor amount (2%) of Diels-Alder adduct 4 (ir realized

by allowing

a benzene

at 25' for 4 days.

G,

R: Me

3a_, Ar: Ph

E,

R: Et

%,

X: 0CH3

Ar: C6H4N02

3c, Ar:

2463

C6H4OCHq

solution

of

2464

No. 29

The and mass

structure

of 2 follows

spectra.

3a shows _

from

ir, H nmr,

a C=O absorption

europium

shift

studies,

13C nmr

at 1695 cm-l.

Et Ph

Downfield

shifts

Complexation

in ppm on Eu(fod)3

of the oxygen

5 with

Eu(fod)3

cially

those

causes

located

the regioisomeric to steric

and electronic

reaction,

relative

This observed case are

suggests

to 3 and

factors

in its borohydride

than

leading

Electron

shift

azide

of vinyl

attacked

with

the pathway

of starting

approximately charge

azides

with

shown

excludes sensitive

materials X speed

in the transition rate

order

state

which

we

In the latter Our

via the B-carbon.

in reaction

scheme

with

up the

6:3:1.

triazolinediones.5 system

product (espe-

This

substituents

to the relative

the unsaturated

reduction B-protons

of 1 to 2. is highly

to recovery

withdrawing

of --1b:la:lc being stabilization of a negative contrast

for the

for the y-protons.

rates

is in direct

in consonance

and

downfield

The cycloaddition

L.

azides.

for the reaction

the vinyl

larger

syn to the oxygen)

styryl

leading

in ketone &

a much

structure

B-substituted the

complexation

data

1.

Scheme By comparison, group

diazoethane

as well Phenyl

(S) reacts

to produce

tion

of B_ is not a fast

the

phenyl

presence

to tetraphenylcyclopentadienone

as at one of the double

azide

60')

2 since

adds

the bridged azide

step

slowly ketones

bonds

with

to produce

of the 2,3-dihydro

toluene

2 in ca. 70% yield.

largely

derivative

of -. 2b

upon

(no reaction

Apparently,

but is dependent

unchanged

at the carbonyl

a dihydropyrazole.6

2_ in refluxing

in the reaction

S remains

1

refluxing

Furthermore,

at

decomposi-

on the presence in toluene phenyl

in

nitrene

of

~0.29

2465

Generated

from

9b is stable photochemical this

Under

addition and

conditions

with

to the indoline

2b Ketone -* 10 upon -

at 350 nm.

to the behavior picryl

azide

to cyclopentadienone.

via oxidation

did not react

by a 1,3-shift

of 3,5_dinitrophenylazide

is analogous

these

and tributylphosphine

but rearranges

irradiation

Reaction and

nitrobenzene

at 200'

with

of sulfonyl

forms

phthalimide. *

the o-pyridone

azldes

with

fi

(33%) tetracyclone. 7

the furazan-N-oxide

2 was achieved

of N-amino

2b to give

using

ethyl

In this manner

12 Nitrene -* azidoformate at 1150 the fused

aziridines

Efforts are under-13 and -14 were formed in 64% and 100% yield, respectively. way to determine the reaction mechanisms in these transformations and the various

factors

that

influence

the pathway

chosen.

Ph

n

Et R: Me

or E+

Ar: Ph; 3,5-kh1C2)2C~Hj

oi-

2,4,6ff”02)3C6H2

-C02Et Ph

2466

No. 29

Acknowledoment This National

investigation Cancer

was

Institute,

supported

by Grant

NO. CA 19203

awarded

by the

DHEW.

REFERENCES 1.

(a) Cycloadditions N. Sartoris, in part

2.

(a) T. Sheradsky

Chem.

3076

z.

4. 5.

A. Hassner,

6.

Muller 7. 8.

Hassner,

A.

(1976);

of the Azide

pp. 373-384; 7301

Ed., 14,

were

see

7698

R. M. Cory

(b) Work

carried

S. Patai,

Ed.,

and out

of Colorado.

(1973) 775

(b) A. Hassner

D. Tang

Group,'

(b) K. H. Houk. and references

J. Sims,

therein;

Inter-

C. R. Watts,

(c) 6. L'Abbe,

(1975). J. Org.

Chem.,

39,

and D. J. Anderson,

characterized

and J.

and A. J. Thommen,

D. J. Anderson, C, 576

Keogh,

and A. Langbein,

and M. El-Chahani,

R. A. Abramovitch Sot.

95,

XXII

98,

by ir, H-nmr,

3070

E.,

(1974); 38,

mass

ibid.

2565

spectra

(1973).

and

analysis.

(a) B. Eistert 6. Fink

Sot.,

and D. J. Anderson,

(1974);

All new compounds elemental

1971,

Intern.

(a) A. Hassner 39,

Chem.

in "Chemistry

Publishers

L. Luskus,

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at the University

science and

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J.

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104 101,

J. Chem.

4l_, 2102

78 (1964);

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(b) 8. Eistert,

(c) B. Eistert,

R.

(1968).

Sot. Chem.

D. C. Horwell

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J. Chem.