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Cobalt Mediated [2 + 2 + 2]-Cycloadditions Stereospecific Intramolecular Reactions of Enediynes to Tricyclic Dienes Bearing Angular Methyl Groups.

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together with a marked broadening of the lines. We interpret these observations as evidence that a bridged complex
containing the grouping Ir-PF2-BH3
has been formed;
in confirmation of this view, the I9F-NMR spectrum consists of a broad doublet, due to ‘J(PF), each line of which
is split into a I :3 :3 : 1 quartet by F-H coupling.
3. The ligands in (2), all of which were either previously
unknown - (2a-d) - o r incompletely characterized (2e,
f j I V - may be liberated as colorless oils in high yield by oxidative demetalationr6] (Table 1). Decomplexation of the
mixtures (2d) and (28 gave only one product, corroborating the structural assignment of the minor component.
~
Received: August 18, 1980 [Z 825 IE]
German version: Angew. Chem. 93. 785 (1981)
(11 W. MaLsch, R. Alsmann, Angew. Chem. 88, 809 (1976); Angew. Chem.
Int. Ed. Engl. IS, 769 (1976).
121 E. A. V. Ebsworth. D. W. H . Rankin. J. D. Whitebck. unpublished results.
cocp
+ +
Cobalt Mediated I2 2 21-Cycloadditions:
Stereospecific Intramolecular Reactions
of Enediynes
to Tricyclic Dienes Bearing Angular Methyl Croups[’*]
/
F
/
By Thomas R . Gadek and K . Peter C. Vollhardt[’l
We recently reported on the inter- and intramolecular
[2 2 2]cycloaddition of linear achiral enediynes containing terminal double bonds, using C ~ C O ( C O )to~ ,give polycyclic diene complexes (cp = cyclopentadienyl)rll. We
now describe similar stereospecific reactions of enediynes
which may even be used to incorporate trisubstituted double bonds, producing tricyclic dienes with angular methyl
groups. The molecules synthesized constitute good model
systems for a variety of polycyclic natural products, particularly vitamin D precursors.
The educts (1) were prepared by Wittig reaction of the
terminal acetylenic aldehydes or ketones with the appropriate acetylenic ylides[’l. The aldehydes o r ketones generally originated from internal propargyl alcohols via the
“acetylene-zipper’’ reactionr3’, followed by standard structural manipulations. Cis- and trans-(1) were interconvertible by irradiation in the presence of sensitizer[41 and, if
necessary, separated by preparative gas chromatography.
In a typical experiment, a solution of (I) and
C ~ C O ( C Oin
) ~boiling m-xylene was irradiated to give the
red-brown complexes (2) (Table 1) in fairly good yield,
after chromatography on alumina. Stereochemical and
spectral assignments were carried out by comparison with
model compounds, utilizing the effect of the anisotropy of
cobalt on the N M R spectra”], symmetry considerations [cf.
(2a) with (2b)], and off-center resonance proton decoupled
I3C-NMR spectroscopy.
Three points of particular interest are:
1. The [2 + 2 + 2]-cycloaddition proceeds with retention
of stereochemistry at the original double bond and also
with remarkable stereoselectivity with respect to cobalt [cf.
(2a), (2b), (2c). (2e)I; this might be valuable in asymmetric
syntheses with an optically active metal compound.
2. The cyclopentadienylcobalt not only fulfills the function of the mediator of the cyclization but also serves to
protect the diene unit from rearrangement and polymerization.
+ +
[*] Professor Dr. K. P. C. Vollhardt, T. R. Gadek
Department of Chemistry. University of California, Berkeley
Materials and Molecular Research Division,
Lawrence Berkeley Laboratory
Berkeley, California 94720 (USA)
[**I
0 Verlag Chemie GmbH, 6940 Weinheim. 1981
(2ri c o c p
(2d) 3 : 2 mixture
COCP
The origin of the stereoselectivity observed in the above
reactions is not clear at present. It should be noted that trimethylsilylation of the alkyne moieties is detrimental to
the successful outcome of the reaction.
Hydrogenated benz[e]indanes and phenanthrenes of the
type synthesized here are frequent structural features in
natural products. The ligands in (2e) and (2fj are of particular interest since they may be regarded as constituting
the ABC-portion of steroids, which function as precursors
to vitamin D and valuable steroid hormones. The cobalt
mediated [2 + 2 + 21-cycloaddition approach should provide a simple and effective route to these classes of compounds.
Procedure
This work was supported by the National Science Foundation (CHE 7903954) and the National Institutes of Health (GM 22479). K P.C. V. is a
Camille and Henry Dreyfus Teacher Scholar (1978- 1983).
802
i
A degassed solution of ( 1 ) ( 1 mmol) and C ~ C O ( C O( 1) .~1
mmol) in m-xylene (50 mL) was refluxed and irradiated
(visible light, GE-ENH, 250 W). After 1 h, the solvent was
removed in uacuo (0.05 torr) and the residue chromato-
0570-0833/81/0909-0802
$02.50/0
Angew Chem. Int. Ed. Engl. 20 (1981) No. 9
Table I. Physical data of the diene complexes (2) and their free ligands. All
new compounds gave satisfactory analytical and/or high resolution mass
spectroscopic values. 'H-NMR (at 250 MHz unless otherwise stated) and
"C-NMR (63 MHz): &values (C6D6); for numbering see (2c) and (2e); ex0
and endo refer to the position of the proton relative to the metal.
(Za): 63%; m.p. 43'C; 'H-NMR (600 MHz): 4.50 (s, 2H, H".'), 4.45 (s, 5H,
Cp), 1.91 (d, J=11.5 Hz, ZH), 1.67 (dd, J=9, 8Hz, 4H),1.63 (dd, J=12, 1 1
Hz,4H),1.35(d,J=11.5Hz,4H),1.23(AA'm,4H),0.62(dd,J=17,11
Hz,
2 H , H,3.,4); I3C-NMR: 80.7 (Cp), 75.5 (C"), 72.5 (C'), 47.0 (C"), 41.1,32.7,
30.7, 28.0
(26): 63%; oil; 'H-NMR: 4.60 (d, J-4 Hz, 1 H, H" or H7), 4.55 (s, 5H, Cp),
4.47 (d, J = 4 Hz, l H , H" or H7), 1.8-1.0 (m,16H), 0.87 (dd, J=6.5,7 Hz,
2H), 0.63(dddd, J= 12.5, 12.5, 12.5,3.5 Hz, 1 H), 0.16 (m,1 H,
"CNMR: 80.1 (Cp), 75.6,75.4,71.7,68.4, 52.9 (C"e"de), 42.9 (C'4ex"),40.6, 36.4.
35.7,35.0, 30.0,27.9,26.8,26.3
K . P. C. Vollhardt, in B. M . Trosf, C. R . Hutchinson: Organic Synthesis
Today and Tomorrow, Pergamon, New York 1981,p. 71.
[31 J. C . Lindhoudt, G. L. van Mourik, H. J. J. Pabon, Tetrahedron Lett.
1976, 2565; C. A . Brown, A . Yamashita, J. Chem. SOC.Chem. Commun.
1976, 959.
I41 C. Moussebois, J. Dale, J. Chem. SOC.C 1966. 260.
151 W. Huber, Ber. Dtsch. Chem. Ges. 718 (1938)725; K . Dimrofh, E. Dietzel, E. Stocksfrom, Justus Liebigs Ann. Chem. 549, 256 (1941); H. B.
Charmbury, C. C. Wright, J. Am. Chem. SOC.66, 526 (1944);E. A . Braude,
0. H. Wheeler, J. Chem. SOC.1955, 329.
I61 E. R . F. Gesing, J. P. Tone, K . P. C. Votlhardt, Angew. Chem. 92, 1057
(1980);Angew. Chem., Int. Ed. Engl. 19, 1023 (1980).
(2c): 65%; oil; 'H-NMR (600MHz): 4.51 (s, 5 H, Cp), 4.47 (d, J=4.5 Hz, 1 H,
H" or H'), 4.43 (d, J=4.5 Hz, H" or H'), 2.56-1.20 (m,14H), 0.90 (m,2H,
H"."); "C-NMR: 80.0 (Cp), 75.3,73.2,50.8, 50.4,41.5,33.3, 33.1, 30.8,28.2,
26.0,22.3 [a]
[(q5-CH3C5H4)Mn(CO),Hg14,a Compound with
an Mn4Hg, Eight-Membered Ring and Additional
Hg-Hg Bonds
(Zd): 63%; oil; 'H-NMR: 5.05 (d, J=4.3 Hz, 1 H, H" or H'), 4.52(s, SH, Cp),
4.46 (d, J=4.3 Hz, 1 H, H" or H'), 2.9-0.6 (m),0.24 (m,1 H, HI2 or H " 7 ;
this spectrum also contains signals assigned to a second isomer (ratio 3 :2) at
4.65 (s, Cp), 4.71 (d, J=5 Hz, H"or H'), 4.47 (d, J-5 Hz, H" or H'), 0.05 (m,
HI2 or H13"O); "C-NMR: 81.2 (Cp), 79.8 (Cp), 74.5,71.4,56.2, 53.2, 48.3,
40.8,36.9, 36.5,35.7,35.2, 34.2, 33.3,29.9, 29.1,27.6, 26.5 (ZC), 26.4, 24.3,
23.3 [a]
(2e): 74%; oil; 'H-NMR: 4.57 (d, 1-4 Hz, 1 H, H" or H'), 4.49(s, 5 H, Cp), 4.43
(d, J=4 Hz, 1 H,H" or H'), 1.93 (ddd, J = 13, 13, 4 Hz, 1 H), 1.80-1.50 (m,
By Wolfgang Gade and Erwin Weiss"]
5H),1.5-1.1(m,l1H),1.34(s,3H,CHI),0.98(ddd,J=10.5,4.5,2Hz,1H),
0.85 (ddd, J= 13, 13, 4.5 Hz, 1 H), 0.62 (dddd, J=12, 12, 12, 4 Hz, 1 H,
H"""); "C-NMR: 80.4 (Cp), 76.7 (ZC), 75.8,72.3, 55.9 (C"), 42.3 (CI4),
41.1,37.5,35.9, 32.3, 31.2, 30.9,29.8 (CH,), 28.3,22.8
(2n:76%; oil; 'H-NMR: 4.72 (d, 1-4 Hz, 1 H, H" or H'), 4.53 (s, 5 H, CsHs),
4.47 (d, J=4 Hz, 1 H, H" or H'), 1.88 (ddd, J= 13, 13,4 Hz, 1 H), 1.78-1.42
(m.8H), 1.41-1.2 (m, 6H), 1.28 (s, 3H,CH,), 0.86 (dddd, J=12, 12, 12, 4
Hz, 1 H), 0.17 (dd, J= 12,0.8 Hz, 1 H, H"); this spectrum also contains signals assigned to a second isomer (ratio 3 : I): 4.53 (s, C5Hs), 4.50 (d, J = 4 Hz,
'), 0.65 (s, 3H,CHI); "C-NMR major
Hh or H'), 4.41 (d, J = 4 Hz, H" Or H
isomer: 79.9,77.7,77.6(ZC), 75.0,48.3 (CC"),44.5 (C'"), 37.1, 36.0, 30.6,26.5,
25.7,22.8, 21.8 (CH3); minor isomer: 80.8, 76.1,75.0,57.2 (C"), 42.6, 42.0,
41.5,33.5, 32.5,28.0,27.9,22.6
cis-l,2,3,4,4a,4b,5,6,7,8-decahydrophenanthrene
[from (2a)]: 93%; 'H-NMR:
5.42 (s, ZH), 2.43 (m,ZH), 2.28 (m, ZH), 2.02 (bdd, J=12, 12 Hz, ZH), 1.80
(m, 6H), 1.27 (m, 6H); "C-NMR: 115.5, 40.5, 35.2,29.0,28.5, 27.0b]
frans-l,2,3,4,4a,4b,5,6,7,8-decahydrophenanthrene [from (2b)I: 96%; 'HNMR: 5.38 (s, ZH), 2.22 (bd, J=13 Hz, 2H), 2.1-1.7 (m, IOH), 1.45-1.15
(m, 6H); "C-NMR: 115.1,44.1,37.1,34.8,28.6, 27.0[b]
cis-I-H-2,3,6,7,8,9,9a,9b-octahydrobeMe]indene
[from (2c)l: 86O/0;'H-NMR:
5.56(bs,ZH),2.93-2.56(m,ZH),2.5-1.1 (m.14H); "C-NMR: 115.5, 113.2,
43.1,42.6,36.5,31.6,30.1, 28.9,27.7., 27.2,24.9 [b]
frans-l-H-2,3,6,7,8,9,9a,9b-octahydrobenzIe]indene[from (Zd)]: 89%; 'HNMR: 5.61 (bs, 2H), 2.6-1.0 (m, 16H); "C-NMR: 119.2, 114.2, 48.4,42.0,
34.7,33.2,32.7,30.2,26.2,25.8, 24.8 @]
Numerous examples of mercury-transition metal compounds having linear M-Hg-M
bridges are known.
We wish to report here on the reaction of
K [ T ~ - C H ~ C , H , ) M ~ ( C O ) , G ~with
H ~ ]Hg2'
~ ' ~ ions in aqueous media, which yields the unexpected Ge-free compound [($-CH3C5H4)Mn(CO),Hg], ( I ) (55%); in addition,
the Hg-free compound [(q5-CH3C5H,)Mn(CO),1,Ge (2)
(1%) is formed, which contains a GeMn double bond as
well as two GeMn single bonds[']. The course of the reaction is still unknown; the observed elimination of mercury
indicates an oxidative action of the Hg2+ ions.
An X-ray structure analysis[31shows a novel ring system
with an Mn4Hg4eight-membered ring in the Hg-containing
compound (I). The molecule possesses a four-fold alternating axis. The four Hg atoms have an almost coplanar
P
cis-l,2,3,4,4a,4b,5,6,7,8-decahydro-4a-methylphenanthrene
[from (2e)l: 84%;
'H-NMR: 5.46(d, J=6 Hz, lH), 5.37 (dd, J=6, 2 Hz, 1 H), 2.27 (m. 3H),
2.0l(ddd,J=12, 12,4Hz,1H),1.94-1.45(m,8H),1.45-1.10(m,5H),1.02
(s, 3H,CH3); "CC-NMR: 116.3,113.9,52.2, 51.9,37.1,31.4,31.2,30.1, 27.8,
26.3,25.5, 25.2, 22.4 [bl
frans-1,2,3,4,4a,4b,5,6,7,8-decahydro-4a-methylphenanthrene [from (.?B]:
92%; 'H-NMR: 5.46 (bs, ZH), 2.46-2.0 (m, SH), 1.92-1.57 (m, 6H), 1.46
(ddddd,J=13,13,13,3,3Hz,1H),1.40-l.14(m,5H),0.87(s,3H,CH3);~3CNMR: 117.6,117.5,48.2,48.0,40.5,32.8,
31.3,30.0,26.4,25.5, 23.9,16.4, 16.0
M
[a] Quaternary C atoms not detected. [b] Quaternary vinyl C-atoms not detected.
graphed on alumina (activity 2, under N2) with pentane.
The diene complex is eluted as a single red-brown band.
Received: February 11, 1981 [Z827 IE]
German version: Angew. Chem. 93, 801 (1981)
[I]E. D. Sfernberg, K. P. C. Vollhanit. J. Am. Chem. SOC.102, 4839 (1980);
C. Chang. J . A . King,Jr., K . P. C. Vollhardf,J. Chem. SOC.,Chem. Commun. 1981, 53.
121 C. Chang. C. G. Francisco, T. R. Gadek. J.A . King, Jr., E. D. Sternberg.
Angew. Chem. I n f . Ed Engl. 20 (1981) No. 9
U
M
Fig. 1. a) Structure of (I) in the crystal, ORTEP-drawing. Mn-Hg 264.0(7),
Hg-Hg 288.8(2), Mn--C(CO) 176(7) and 179(8), M n - C ( C p ) 209(9) to
218(5), average 212.4 pm; Mn-Hg-Mn
157.2, Hg-Mn-Hg
66.2(2),
Hg-Mn--C(CO)
7q2) and 118(2), C ( C O ~ M n - - C ( C O ) 87(3)". Crystal
data: tetragonal space group 15, a = 1595.9(2), c=768.3(1) pm, V =
1956.8x 10" pm', 2=2, p(calc.) 2.64 g cm-'. Mo,,radiation,
986 independent reflections (up to @= 30"), R = 0.099 (Mn and Hg anisotropic, C and
0 isotropic). b) Projection of (I) at right angles to the plane of the molecule,
two of the Mn atoms shown without ligands.
[*] Prof. Dr. E. Weiss, Dr. W. Gade
lnstitut fur Anorganische und Angewandte Chemie der Universitat
Martin-Luther-King-Platz 6, D-2000 Hamburg 13 (Germany)
0 Verlag Chemie GmbH, 6940 Weinheim, 1981
0570-0833/81/0909-0803 $ 02.50/0
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angular, intramolecular, stereospecific, reaction, cycloadditions, group, cobalt, tricyclic, mediated, methyl, diener, enediynes, bearing
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