Co(acac)2-organophosphorus activator-AiEt2Cl (1:1.5-10, 80~ ... The nature and concentration of the organophosphorus ligand activator proved to have a con-.
ORGANIC CHEMISTRY
C00LIGOMERIZATION OF 1,2-DIENES WITH NORBORNADIENES CATALYZED BY OOBALT COMPLEXES U. M. Dzhemilev, R. I. Khusnutdinov, Z. S. Muslimov, and G. A. Tolstikov
UDC 542.97:541.64:547o315.1:547.599.2
Cooligomerization of olefins, 1,3-dienes, and acetylenes with norbornadiene (NBD) under the action of transition metal complexes, which opens up a direct route to strained polycyclic compounds which are difficult to access, is sufficiently well known [I]. Analogous reactions of allene compounds with NBD have been little studied. In particular, the [27 + 27] cycloaddition of an allene to NBD in the presence of Pd catalysts [2] and [27 + 2~ + 27] addition of l,l-dimethylallene to NBD in the presence of Fe catalysts [3] have been reported~ At the same time, there is no information on the influence of the structure of the initial norbornadienes and allenes on the direction and selectivity of the reaction nor on the possibility of obtaining codimers of NBD derivatives and substituted allenes by a [27 + 27 + 2~] cycloaddition. In the present work our object has been the synthesis of new types of strained polycycles of the tetracyclononane series built up from three-, four-, and five-membered rings, and for this purpose we have studied the cooligomerization of NBD and spiro{bicyclo[2~ hepta-2,5-diene-7,1'-cyclopropane} (I) with aliene, cyclopropylallene (CPA), phenylallene, and 1,2-cyclononadiene by a [2v + 2~ + 27] cycloaddition catalysed by low-valence Co complexes.
+
CH=-----C~ICH~~
+
+
(II)
(ni)
+
(Iv)
(v)
Thus, from allene, taken in excess, and NBD in the presence of a catalyst system Co(acac)2-organophosphorus activator-AiEt2Cl (1:1.5-10, 80~ 1 h, toluene) a mixture of the hydrocarbons (II)-(V) in the ratio 5:2:1:3 was obtained in overall yield of 93% with a predominance of 8-methylenetetracyclo[4o3.0.02,~.03,?]nonane (II). Because of the complications of measuring the gaseous allene in the course of the reaction the cooligomerization of 1,2-dienes with NBD was studied using CPA as an example. It should, however, be emphasized that the reaction of CPA with NBD differs from that with allene in that it proceeds with the formation, in addition to the three isomers of tetracyclo[4o3.0.O2'~.O~,~]nonane (delta cyclene) structure (VI)-(VIII), C16-polycycles of a new type - lO-cyclopropylmethylenehexacyclo[ll.2.1.O2,12~ (IX) the concentration of which in the reaction mixture can reach 37%.
~ + .
~
CH~---C~Ctt-~
(vl)
(vn
(vm)
+
(v)
(ix)
Bashkir Branch, Academy of Sciences of the USSR, Ufa. Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 6, pp. 1346-1356, June, 1988. Original article submitted November 4, 1986.
0568-5230/88/3706-1183512.50
9 1988 Plenum Publishing Corporation
1183
TABLE i. Effect of Nature and Concentration of Organophosphorus Activator on Isomer Composition and Yield of Products in the Reaction o#~ with Cyclopropylallene (Co(acac)2: AIEt=CI:CPA:NBD = 1:10:200:200, 80~ i h, Tolune) Organophosphorus ' I Molar ratio t Overa~ yield I activator (L) [Co(acac)z'.Ll orco011- . i - I gomem (v), ~ ,.
I
[(vi)-(ix~.
% L'-'
t Higher
Com posTfio~~0 (VII) + + (YIII) *
(ix)
(v)
0 P{h~ PPhs
t:i i : t,5 l :2
PPhs
(o-MeC,H,) Ph~P Ph,PCH~PPh2 Ph2PCH~CH2PPh2
i:t,5 i:t,5 i : t, 5
"--"
oligomers,
iO0
85
93 86
32 40
80 8t
40
II
30 32 27
i0
28 35
20 10 22 12 10
i5 7 8 i3 t7 i5
*Isomers (VII) and (Vlll) formed in ratio 2:1. The nature and concentration of the organophosphorus ligand activator proved to have a considerable effect on the yield and composition of the products of this reaction (Table I). The optimum ratio of Co(acac)2:PR 3 is 1:1.5 to 1:2. In the absence of a ligand activator Co(acac)2-AiEt=Cl, NBD, and C ~ give higher oligomers which were not identified. The use of bidentate ligands, 1,2-bis(diphenylphosphino)ethane (BPE) or 1,2-bis(diphenylphosphino)methane (BPM), made it possible to suppress the formation of the polycycle (IX) completely. However, even the use of biphosphines did not make it possible to suppress the homodimerization of NBD into the binor-S (V). The ratio of the starting materials has a considerable effect on the yield and composition of the reaction products (Table 2). It would appear that an excess of CPA plays the part of an activatingligand and in this role it is more effective than a bisphosphine~ For example, with a ratio of CPA:NBD = 2:1 the homodimerization of N ~ is completely blocked and this effect holds for all the allenes which we have studied. I n the light of what has been said, the reason for the absence of hydrocarbons of the type (IX) from ~ o n g the reaction products becomes ~derstandable, since their formation requires the participation of two molecules of ~ D . The reaction of phenylallene with N ~ under conditions found to be optimal results in a 56% yield of the two isomeric deltacyclene hydrocarbons (X) and (XI) and the binor-S (V) in the ratio 3:2:1.
(x)
(xl)
Ph
The result of the codimerization of NBD with 1,2-cyclononadiene is exceptionally interesting
tt--', +
(y)
(xm) (XI!)
The ratio of (XII):(XIII):(V) is 3:2:1.5. The main isomer (XII) is typical of a product of a [2~ + 2~ + 2~] cycloadditionof allene and NBD. Parallel with this, a [2~ + 2~] cycloaddition takes place with the formation of compound (XIV) which, under the reaction conditions
1184
TABLE 2. Effect of Molar Ratio of Monomers on the Yield and Composition of the Products of Cooligomerization of Norbornadiene with Cyclopropylallene Co(acac)2:PPh3: AIEt2CI:NBD = 1:1.5:10:200, 80~ I h, Toluene Ove rail Molar ratio I yieldof NBD : CPA- I(V), (VI)-
/(IX), ~o
(vi)
(vii) + (viii)
(ix)
(v)
4 3 ii 14 t8 27
13 37 3O 25 12
70 40 20 15 5
8
95 95 93 94 92 92
1:0.2 I : 0,5 i:i t:1,2 i:1,5 1:2
Composition, %
9
32 40 57 65
Higher oligomers, % 5 5 7 6 8 8
used, undergoes isomerization into the final product (XIII) (scheme A). The mechanism of this isomerization is not fully clear; in any case, examples of similar reactions in the methylenecyclobutane series have not been discovered. The known isomerization mechanism (scheme B) does not explain the formation of the 1,4-diene (XIIi). Reactions of allenes with spiro{bicyclo[2~ (I) takes place in a similar manner. Thus, in the cooligomerization of al~ene with (I) a mixture of (XV), (XVI), (XVII), and (XVIII) is formed in the ratio 3:0.7:0.3:2 with an overall yield of 78%.
+
'
_ _
---.---',- ( X i l l )
(A)
r
),
~
"
):
(B)
[Co]
(xyni) (xv)
(xvi)
(xvli)
Reaction Of (I) with CPA gives a mixture of hydrocarbons olose in composition and yield to the mixture formed in the analogous reaction of NBD with CPA. Thus, the concentration of the hydrocarbon of type (IX) in this mixture reaches 28%. Separation of the cooligomers (II)-(IV), (X)-(XIII), and (XV)-(XVIII) in individual form presented considerable difficulties. Fractionation and GLC proved not to be very effective. The best results .were obtained using high performance liquid chromatography with reversed phases. A search for optimum conditions led to the use of ~-Bondapak C18 as an analytical column and for preparative work a semipreparative column of Zorbax ODS. By this means we succeeded in separating the cooligomers (II), (VI), (IX), (X), (XI), (XI!), (Xlil), and (XV) as individual species. The isomer ratios (III):(IV), (VII):(VIII), and (XVI):(XVII) were determined from carbon-13 NMR data. The cooligomers of (I) with CPA, phenylallene, and 1,2-cyclononadiene were obtained in yields of 73, 54, and 46% respectively. The isomeric cooligomers in this case were characterized in the form of mixtures. The structures of compounds (II), (V), (XV), and (XVlII) were established by comparison of their characteristics with those given in [4-6]. Proof of the structure of the remaining compounds was obtained on the basis of proton and carbon-13 NMR, IR, and mass spectroscopy. Assignment of the
1185
Co
e~
b~
o
0
01
o
o
I-h
f-t
I
TABLE
3 (Continued) IIIII
C9
1t,36 d
I t,36
d
157,99 S
C'~
C"
15.52 d
35,95 t
15,52 d
35.97 ] it0,83 ii0~39 t t t
[02.99 t
14.37 d
32,25 t
[22,13
35,t2 t
122,91 ! li,I0
35,05
[40A5
d
t56,36 $
d
s
s
t05.70t
C':
C~
C~
C=a
6,46 t
6,46
d
t
35A5 t
C,r
i,74 t
d
!
Ct6
II0,83 1t0.83 t t
t0,84 i
CL=
~
42,95 49,20 138,6t i d d d
4,t02 128,84
d
~ii
i
?,
6,8i t
t43.47s 127,80 128.82 d
1187
TABLE 3 (Continued)
C2
Compound
