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Cycloaddition to Homofulvenes.

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quently the case in photochemical reactions, the yields are
low: 15 to 20 mg from a 100 ml volume of gas (or solution).
Received: December 1 I , 1969
[Z 136 1El
German version: Angew. Cheni. 82, 182 (1970)
Detailed information about the composition and structure of
compounds ( I ) and (2), which readily sublime at room
temperature, was provided by their 70 eV mass spectra. The
signals of highest intensity are due to the fragments
M(CF2)zM ' ( M ~= Fe, C o ) ;other signals occurring are those
due to the molecular ions and the dissociation products
resulting from CO cleavage as well as those of the fission
fragments of M(CF2)2+. The 1R spectra of the complexes
(see Table) are also in accord with the proposed structures:
the spectra show that compound ( I ) contains a bridging CO
group whereas compound ( 2 ) does not. The compounds are
diamagnetic and therefore must contain metal-metal bonds.
( I ) and (2) are readily soluble in organic solvents such as
ether, petroleum ether, benzene, or methanol and crystallize
therefrom in the form of yellow needles. Just as F e 2 ( C 0 ) 9 is
more stable than Coz(C0)8. compound i l ) is more stable
than (2) in air; however, it melts at 104°C with decomposition. i 2 ) sublimes at 45 "C under atmospheric pressure
If a solution of Fe(C0)S i n CFZBrZ is subjected to irradiation,
tetracarbonylbis(bromodif7uoroorange-yellow,
volatile
methyl)iron (CFzBr)zFe(C0)4 (3) is formed. This compound, which is probably a precursor of ( I ) , was also characterized by its IR (cf. Table) and mass spectra. Since ( 3 )
exhibits more than *one JR-active CO absorption band it
must be present in the cis-form. The signals of the molecular
ion and fragment ions in the mass spectrum of ( 3 ) exhibit
triplet and doublet structure as a result of the isotopy of
bromine.
Table. CO bands (cni-1) of the 1R spectra of [ I ) , (2) and 13) in 11hexane solution, of Fez(C0)9 in the solid state, of Co2(CO)s (bridge
form) in n-hexane, and of cis-Fe(C0)4Br2 in chloroform.
Fez(C019 (21
2082 s
2019 vs
1829 vs
[*I Prof. Dr. F. See1 and Dipl.-Chem. G . V. Roschenthaler
Institut fur Anorganische Chemie der Universitat
66 Saarbrucken (Germany)
[ l ] Type TQ 81, Quarzlampen GmbH Hanau.
[ 2 ] F. A . Cotton, A . D.Liehr. and G . Wilkinson, J. inorg. nuclear
Chem. I , 175 (1955).
[3] G . Bor, Spectrochim. Acta 19, 1209, 2065 (1963).
[4] R . C. Toylor and W. D.Horrorks, Inorg. Chem. 3 . 584(1964).
Cycloaddition to Homofulvenes
By Roiner Asktrni 1 * I
Whereas [6 + 21-cycloadditions with fulvenes as 6;r-electron
components are still unknown, the homofulvene derivatives
e.yo- and endo - 1,2,3,5,6 - pentamethyl - 4 - methylenebicyclo[3.1.0]hex-2-ene ( l a ) and ( I b ) 111 have been found to undergo
homo-[6 + 21-cycloaddition with N-chlorosulfonyl isocyanate to give the adducts (3a) and (3b), respectively, the reaction involving inversion at C-6. This finding is in accord
with the requirements for a symmetry-allowed concerted reaction of the kind [(02a r4s) + %2J, while a corresponding
reaction of fulvenes, being a [r;6s + .2,] process, is symmetryforbidden[*]. A further possibility in the case of N-chlorosulfonyl isocyanate, i.e. that the reaction proceeds stepwise,
would require stereospecific opening of the three-membered
ring since n o products exhibiting retention could be detected
alongside those that had undergone inversion at C - 6 .
Reaction of ( I n ) and ( I b ) with N-chlorosulfonyl isocyanate
is assumed to give initially l2u) and (2b), respectively, which
are converted into the conjugated isomers (3u) and (3b) by
a n allylic hydrogen shift under the reaction conditions[**].
Since only one product can be isolated in each case, this shift
must be stereospecific; however, the available spectral data
provide no definite information about the steric course. The
conversion of both (3u) and (3b), via the acids (4a) and (4b)
and the esters (5a) and (561, into the same ketone (6) shows
+
co2(co)st3l
2112 vw 1866 m
2071 vs 1857s
2044 vs 1832 vn
2031 s
2001 w
x
cis-Fe(CO).+Br*[41
OCN-S02CI
H
2155 w
2112 s
2109 s
2082 s
( l a ) , X = H, Y = CH,
( I b ) , X = CH,, Y = HIa1
Experimentul:
For the preparation of ( I ) equimolar amounts of Fe(C0)s
and CFZBr2 are introduced into a n evacuated quartz glass
reaction flask at 0°C (p r 8 0 t o r r ) and the resultant gas
mixture is irradiated; for the preparation of (2) and (31,
0.03 M solutions of Co(CO)3NO and F e ( C 0 ) 5 in CFzBrZ
resp. are subjected to irradiation.
Reaction is complete in about 3 hours, when dark colored
reaction products are deposited on the walls of the reaction
vessel. Termination of the gas reaction can be recognized by
a cessation of the pressure increase that accompanies evolution of carbon monoxide and tetrafluoroethylene. After
pumping off the gases and excess starting materials compound ( I ) can be sublimed into a cold-trap (liquid nitrogen)
and recrystallized from petroleum ether. The suspensions
containing (2) and ( 3 ) must be filtered under nitrogen before
evaporation in vacuum. The pure compounds can be sublimed onto a cold finger (Dry ice) in high vacuum. As is freAngew. Chem. internat. Edit. J Vol. 9 (1970)
No. 2
(4u), (4b). R = H
(Su)> (Sb), R = CH,
mo
H,C H y.., X
[a] This assignment is retained in the subsequent formulas; the lines
radiating from the rings signify methyl groups.
167
Cpd. [a1
m.p. ("C)
N M R [bl
U V (nm)
1R (cm-1)
(E)
(3d
123-124
4.10(s) =C-H, 5.60
(4, J = 6.5 Hz)
0-C-H,
7.44
(4. J = 7.0 Hz) C-H,
8.02 (m) 8.13 (m), 8.44
(d, J = 6.5 Hz), 8.83
(d, J = 7.0 Hz),
9.05 (s) CH3
11 :1 :1:3:3:3:3:3
(CDCIdI
vC-C
1620(m)
1590 (s)
vC=N 15OO(s)
vSOz 1350(s)
I 170 (s)
(KBr)
328
(28 300)
(dioxane)
(36)
100-I01
4.25 (s) =C-H, 5.00
(4. J
6.5 Hz)
0-C-H,
7.26
(4, J = 7.0 Hz) C-H,
8.05 (m), 8.12 (m), 8.6.
(d, J = 6.5 Hz), 8.82 (s
8.85 (d, J == 7.0 Hz)
CH3 [1:1:1:3:3:3:3:3
(CDCldl
vC=C 1620(m)
1590 ( s )
vC=N 1500 ( s )
VSOZ 1 3 5 0 ( ~ )
1170 (s)
WBr)
33 I
(28200)
(dioxane)
(44
161-165
(46)
160-161
(50)
86-87
(56)
oil
(6)
87-88
168
7
4.50 fs) -=C--H. 5.79
(4, J .- 6.5 Hz)
0-C-H,
1.62
(4,J - 7.0 Hz) C-H,
8.15 (m), 8.22 (m),
8.65 (d, J = 6.5 Hz),
8.92 (d, J = 7.0 Hz).
9.08 (s) CH3
[l :I :I :3:3:3:3:3
(CDCldl
vC 0 1680(s)
vC-C 1640(m)
I600 ( s )
WBr)
278
(20200)
(dioxane)
176)
124-125
4.50 ( s ) --C-H, 5.37
(4,J - 6.5 Hz)
0--C-H, 7.34
(4. J = 7.0 Hz)C-- H ,
8.15 (m), 8.23 (rn),
8.74 (d, J := 6.5 Hz).
8.81 ( s ) , 8.93
7.0 Hz) C H J
(d. J
[I :1:1:3:3:3:3:3
(CDCIdI
VC - 0 1680 ( s )
vC - C I640 (rn)
1610 ( s )
(KBr)
282
(18400)
(dioxane)
~
[a] Satisfactory analytical resulrs were obtained for all compounds.
[bl TMS as internal standard, r scale.
4.13 (s) -C-H, 4.66
(4, J
6.5 Hz)
0-C-H,
6.90
(4,J = 7.0 Hz) C-H,
8.23 (m), 8.27 (s),
8.37 (m), 8.87
(d, J = 6.5 Hz), 8.89
(d, J = 7.0 Hz) CH3
[I : I : I :3:3:3:3:3
(pyridine)]
vC-0 1680(s)
vC=C 1640(m)
1590 (s)
(KBr)
283
(20000)
(CHsOH)
3.93 (s) -:C-H, 4.76
(4. J = 6.5 Hz)
0-C-H
6.94
(4, J = 7.0 Hz) C-H
8.27 (m), 8.39 (m),
8.43 ( s ) , 8.69
(d, J = 6.5 HE), 9.00
(d, J = 7.0 Hz) CH3
[ I :I :1:3:3:3:3:3
(pyridine)]
vC=O 1680(s)
vC=C 1640 (m)
I590 (s)
(KBr)
285
(19500)
(CH3OH)
4.62 (s) -C-H, 5.30
(4,J = 6.5 HZ)
0-C-H,
6.40 (s)
OCH3, 7.23
(4, J = 7.0 Hz) C-H,
8.15 (m), 8.35 (m),
8.68 (s), 8.97
(d, J = 7.0 Hz), 9.18
(d, J = 6.5 Hz) CH3
[1:1:3:1:3:3:3:3:3
(CCWl
vC=O 1700(s)
vC= C 1640 (m)
1590 (s)
(CC14)
283
(23 800)
(ether)
4.47 (s) -C-H, 5.53
(4,J = 6.5 Hz)
0-C-H,
6.35 (s)
OCH,, 7.24
(4, J = 7.0 Hz) C-H,
8.17 (m), 8.33 (m),
8.84 (s), 8.96
(d, J = 6.5 Hz), 8.97
(d, J = 7.0 Hz) CH3
[1:1:3:1:3:3:3:3:3
(CCl4)l
vC=O 1700(s)
vC=C 1640(m)
1590 ( s )
285
(23 600)
(ether)
4.25 (s) =C-H, 6.20 ( s )
OCH3, 7.21
(4,J = 7.0 Hz) C-H,
7.92 (s) COCH3,
8.05 (m), 8.17 (m),
8.72 (s), 8.92
(d, J = 7.0 Hz) CH3
[1:3:1:3:3:3:3:3
(CDCWl
vC-0 1 7 0 0 ( ~ )
vC=C 1640 (m)
I590 (s)
(KBr)
7
/7a)
177- 178
that the adducts (30) and (3bj differ only in the configuration
of the carbon atom bound to the oxygen[31. The JH-NMR
signals of the group X-C-Y
in (3a) and (3b) and of t h e
lactones ( 7 ~ )and (76) accessible from (40) and ( 4 b ) , respectively, (benzene, p-toIuenesulfonic acid, water separator)
suggest that inversion at C-6 takes place during the addition
to ( I ) .
Methyl 2-(2-0cetyl-2,3,4,5-tetramethyl-4-cyclopenlen-I-ylidene)acetate ( 6 )
A solution of N-chlorosulfonyl isocyanate (2.0 g) in ether
(30 ml) is added dropwise to a solution of ( l a ) or ( I b ) (2.0 g)
in ether (50 ml), to which a small amount of anhydrous
potassium carbonate has been added, at -60 ' C . The reaction
mixture is kept at -6OOC for another hour, permitted t o
warm up to room temperature overnight, and then filtered.
The filtrate is evaporated down t o a volume of about 10 m1
and placed in a refrigerator; pale yellow crystals of (3ai
(2.2 g, 59
or (3b) (1.2 g, 32 %) are precipitated.
A solution of (3a) or (3b) (1.5 g) in dioxane (40 ml) is permitted to react for 24 h, with stirring, at 60 O C with a solution
of potassium hydroxide (4 g) in water (30 ml). The aqueous
phase remaining when the dioxane is distilled off is extracted
with ether and acidified with hydrochloric acid. ( l a ) or (4b)
(0.8-0.9 g , 70-80 %) is obtained.
A solution of 1.0 g of the ester (5a) or (Sbj, obtained in 85
to 90 % yield from (4nj or (46) o n reaction with diazomethane, in acetone (5 ml) is treated with a solution of
chromium trioxide (1.0 g) in water (5 ml) and conc. sulfuric
acid (1 ml). After 10 min, water (100 ml) is added to the reaction mixture and the product ( 6 ) t0.9 g, 90 %) is extracted
with ether.
x)
Received: November 24, 1969;
revised: December 16, 1969
[Z 137 IEI
German version: Angew. Chem. 82, 176 (1970)
(CC14)
[ * ] Dr. R. Askani
283
(22200)
(dioxane)
Institut fur Organische Chemie der Universitat
75 Karlsruhe, Richard-Willstatter-Allee(Germany)
[ I ] W. Schafer and H . Hellmann, Angew. Chem. 79, 566 (1967);
Angew. Chem. internat. Edit. 6, 518 (1967); R . Criegee and
H . Griiner, Angew. Chem. 80, 447 (1968); Angew. Chem. internat. Edit. 7, 467 (1968).
121 R . B. Woodward and R . Hoffmann, Angew. Chem. 81, 197
(1969); Angew. Chern. internat. Edit. 8, 781 (1969).
[**I Note added in proof(January 31, 1970): If acetylenedicarboxylic esters, azodicarboxylic esters, maleic anhydride, or
tetracyanoethylene is used as reactant instead of N-chlorosulfonyl isocyanate the adducts corresponding to (2) are isolated.
[3] According to the N M R spectra the configuration of the second H-C-CH3 is identical in (3a) and (3b); the same also
applies to (57) and (Sb).
Angew. Chem. internat. Edit.
/ Vol. 9
(1970)
1 NO.2
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