Endo addition of chlorosulfonyl isocyanate to norbornadienes

Endo addition of chlorosulfonyl isocyanate to norbornadienes

Letters No. 52, pp 2953 - 2956. @Pergamon Press Ltd. 1979. Printed in Great Britain. Tetrahedron END0 ADDITION OF CHLOROSULFONYL ISOCYANATE TO NO...

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Letters No. 52, pp 2953 - 2956. @Pergamon Press Ltd. 1979. Printed in Great Britain.

Tetrahedron

END0 ADDITION

OF CHLOROSULFONYL

ISOCYANATE

TO NORBORNADIENES

Paul H. Mazzocchi*, Theodore Halchak and Herman Department of Chemistry University of Maryland College Park, Maryland 20742

L. Ammon

SUMMARY The addition of chlorosulfonyl isocyanate to several bornadienes affords endo and -exo addition products. Recently

has been 1 norbornadienes. With

tuted

additions,

there

the preponderance

a great

deal of interest

respect

to inverse

of s-end0

substituents

(i.e. 3b) has been explained -_ la bond by the sllbstituent.

double

obtained

by specific

nor-

in additions

electron

adducts

7-substituted

to 7-substila-c Diels-Alder

demand with

certain

activation

7-

of the syn

R +

&

i

“6

b RIO+

4

C R- OCOC6H5

The addition diene

has been

adducts

of chlorosulfonyl

shown

in 86% and 94% yield

of 7-substituents our initial

results.

to norbornadienes.

NMR(CDC13)

63.3

with

(m, 3H),

1770 cm-1.4,5

phase

(CSI) to norbornene

by exo addition 2 respectively. We initiated on the mode

constitute

the exo

a study

of the effects

of CSI addition

the first

and norborna-

to give

case of endo

and we now report addition

of CSI

Addition

treatment

IR(CHC13)

These

isocyanate

exclusively

in norbornadiene

subsequent

aqueous

to occur

of 7-phenylnorbornadiene (la) __ to CSI in CHC13 3 Na SO -KOH gave a 37% yield of the exo-8-lactam 2 3 3.75 (m, 2H), 6.2 (m, 2H), and 7.2-7.4 (m, 5H),

A second

and was preliminarily

crystalline

product

characterized

2955

was

isolated

as the amide

from the

alcohol

8a: __

and 6a:

No. 32

H5C20C0

OH 10

NMR(DMSO-d6)

61.3-2.1

(m, 3H), 2.2-2.4

4.8-6.7

(broad, exchangeable, -1 ; mass spectral and 1460 cm 167 respectively.

The yield

Confirmation was provided smooth

(m, 2H),

3.4

parent after

3650,

(s, lH),

3490,

ion and base peaks

several

of the structure

by brief

conversion

(m, 2), 3.0

3H), IR(KBr)

(s, 5H), and

3200,

at m/e

recrystallizations

and endo orientation

7.4

3360,

1690

229 and m/e (H20) was

l58.

of the amide-alcohol

treatment

of 8a with HCl-EtOH which resulted in its *-_ 9a: 6 NMR(CDC13) l-7-2.0 (m, 3H), 2.55-2.75 (m, HB); 7.35 (s, 5H); IR(CDC13) 1785 cm -1 .

to the lactone

(s, lH), 4.95

Treatment

of lc with CSI and aqueous workup afforded the corresponding __ 9c (IR(CDC13) 1785 and 1725 cm -1) , 7 in addition to the B-lactam 5c. __ __ A tentative assignment of the orientation of the bridge substituent with relactone

spect

to the lactone

carbonyl in 9a and 9c was made by comparing the chemical -.__ of Ha in 9a vs 9c. Proton HA is deshielded by the bridge carbonyl group __ I_ by approximately 0.2 ppm in 9c (62.9) vs 9a (6-2.65) whereas the HB chemical __ __ shifts are quite similar. shifts

This

assignment

9a _-. (Fig. 1). phite crystal are:

(2)O; 2 = 4.

ground.

R

Data were

collected

monochromatized

monoclinic,P21/n;

20 of 500.

matrix

was confirmed

Intensities

were

radiation

squares

([xw(~_-~~)~/Zw&~]%

solved

technique.

f actors

FACS-I

with

by direct The final

were

methods R

determination

diffractometer 2

with

gradata

c = 20.769(4) _

more

than

and refined

(CIFo-Fcl/CFo)

and 0.037.

on

The crystal

the O-28 scan method

reflections

are 0.038

x-ray

(X = 0.71069)

b = 8.402(l),

measured

1276 of the 1822 unique was

crystal

on a Picker

MoK

5 = 5.967(l),

The structure least

by a single

8,g

= 93.66-

to a maximum

3a above

back-

by the full

and weighted

No. 32

2955

Figure Evidence frared

for the intermediacy

spectrum

(C=N) and 1820 appear

ORTEP

I

of the reaction

immediately

of lactone

of 7 was provided

mixture

absorption

(C=O) cm-l

Drawing

on CSI addition

9a __

by examination

(la + CSI) which __

showed

of the in-

strong

from 7a and 5a respectively. _,.. Iand their relative intensities

1610

These

bands

do not change

on standing. Speculation must

on the nature

of the transition

states

leading to 7a and 5a *_ __ of 2 is essentially

be consistent

with the fact that the 5a/7a ratio __ _.. invariant 8 in solvents of widely different dielectric

EtBr,

CH3CN)

These

(kCH5CN'kCClq=10)' in these reactions leading

results

and that

to 7 and 5 are quite

similar.

mechanistic

by the electron

and would

result

ance of lactone

hypothesis

deficient

addition

the isomeric

l-substitution products.

in the rate of endo hope

to be able

gations

results

This

addition

to answer

norbornadienes

with

could

that

7-phenyl

state.

lactone

The preponder-

which

would

result

is some preference

increase

from either

for

in the yield

a significant

we have

finished

of CSI additions substituents

of

increase

in the rate of exo addition.

when

and kinetics

states

either initial -exo or endo of CSI at a double bond,

these

in a dramatic result

or a decrease

p-substituted -

of the transition

transition

(unisolated)

this question

on the stereochemistry

carbon

polarized

anti-end0 attack, indicates -___ la over -anti-end0 attack.

endo

involves

carbonyl

in the required 9 over

the polarities

from initial syn-endo -Clearly

(CC14, CHC12,

to la is quite solvent dependent __ that the transition states involved

suggest

are polar

A reasonable attack

constants

but the rate of CSI addition

We

our investito a series

(F, H, CH8,

of

OCH5).

2956

No.

37

Acknowledgement We thank the Computer Science Center of the University of Maryland and the National Science Foundation (CHE-7823808) for partial support of this work. References and Footnotes 1.

(a) Battiste, M-A., Timberlake, J.F., Malkus, H., Tetrahedron E., 2529 (1976); (b) Byrne, L.T., Rye, A.R., Wege, D., Aust. J. Chem., 22, 1961 (1974); (c) Astin, K.B., Mackenzie, K., J. Chem. Sot-, Perkin Trans. G, 1005 (1975); (d) McLean, S., Findlay,D.M.,%trahedron E., 2219 (1969); (e) Wilt, J.W., Malloy, T.P., 2. Org. Chem., 38, 277 (1973); (f) Wilt, J.W., Sullivan, D.R., J. Org. Checc, 1036 (1975); (g) Wilt, J.W., Roberts, W.N., 2. Org. Chem., 43, 170 (1978); (h) FranckNeumann, M., Sedrati, M., Angew. Chem., Int. Ed. a., LI_, 606 (1974); (i) Jefford, C.W., Mareda, J., Gehret, J>. E, Kabengele, nT., Graham, 98, 2585 (1976); (j) Jefford, C.W. W.D., Burger, U., J. Am. Chem. e., 703 (1976); (k) de 10s Heros, V., andBurger, U., Tetrahedron s., 707 (1976); Klumpp, G.W., Kwantes, P.M., Klumpp, G.W., Tetrahedron e., Veefkind, A.H., deGraaf, W.L., Bickelhaupt, F., Ann. Chem., 706, 47 -(1967).

2.

Moriconi, E.J., and Crawford, W.C., IL. Org. Chem., 33, 370

3.

Durst, T., and O'Sullivan, M.J., J. Org. Chem., 35, 2043 (1970).

4.

All new compounds gave acceptable elemental analysis (C,H,N).

5.

The exo stereochemistry follows from the analysis of the NMR couplings. See ref. 2.

6.

Prolonged treatment of 9a __ __ with EtOH-EICl afforded the alcohol ester 10.

7.

This material was originally isolated by Moriconi and Crawford (ref. 2) but its structure was not assigned. They reported an 11% yield of 5c __ and we have isolated 9~ in 10% yield.

8.

Determined by NMR using the olefin proton and HB resonance in 5 and z respectively. HB was assigned to a resonance at 5.26. An additional peak (l/3 the intensity of the 5.26 peak) at 5.06 was observed in all cases and was tentatively assigned to the isomeric imino lactone formed via initial anti-end0 attack. This material may have been lost during work-up. Inxportof this hypothesis preliminary experiments with 7-(p-methoxyphenyl)norbornadiene indicate that in this case we isolate a mixture of isomeric lactones in a 3:l ratio. We are presently working on the separation of these materials.

(Receivedin USb 26 kpril 1979)

(1966).