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Bis(pentamethylcyclopentadienyl)(3-trimethylenemethane)zirconium A New Mode of Bonding for the Trimethylenemethane Ligand.

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[6] H. Tokuyamd, S. Yamago, E. Nakamura. T. Shiraki, Y. Sugiura, J Am. Chem.
SUC.1993, ll5, 7918-7919.
[7] S . H . Friedman. D. L. De Camp, R. P. Sijbesma, G. Srdanov, F. Wudl, G. L.
Kenyon. J A m . Chem. SOC.1993. 115. 6506-6509.
[ X I R. F. Shinazi. R. Sijbesma, G . Srdanov, C. L. Hill, F. Wudl, Anfimicroh. Agents
C1irinofht.r. 1993. 37, 1707-1710.
[9] H. Tokuyama. E. Nakamura, J OrE. Chem. 1994, 59, 1135-1138.
[lo] L. Perrouault. U. Asseline, C. Rivalle, N. T. Thuong. E. Bisagni, C. Giovannangeli. T. Le Doan, C. Helene, Nururi, 1990, 344. 358-360.
[ I l l T. Le Doan. D . Praseuth. L. Perrouault, M. Chassignol. N . T. Thuong, C.
Helkne. Bio~~unpgate
Chem. 1990, 1 . 108-1 13.
[12] J. L. Mergny. G. Duval-Valentin. C. H. Nguyen, L. Perrouault. B. Faucon, M.
RougCe. T. Montenay-Garestier, E.. Bisagni, C. Helene Science 1992, 256,
1681 1684.
[13] H . Tokuyama, M. Nakamura. E. Nakamura. Terraht,dron Lett. 1993, 34,
7429 7432.
[14] A. S . Boutorine. T, Le Doan, J. P. Battioni, D. Mansuy, D. Dupre, C. Helene,
Bioconliigutt~Chent. 1990, I, 350-356.
Bis(pentamethylcyclopentadieny1)(q -trimethylenemethane)zirconium: A New Mode of Bonding
for the Trimethylenemethane Ligand
Gerhard E. Herberich,* Carsten Kreuder, and
Ulli Englert
Trimethylenemethane (tmm) forms a multitude of q4 complexes with transition metals."] For complexes of the early transition metals, only [Cp*TaMe,(tmm)][2"1 (Cp* = q5-C,Me,)
(tmeda =
and recently [Cp*Zr(tmm)(p-CI),Li(tmeda)]~2"1
N,N,N',N'-tetramethylethylenediamine)have been described to
date.
[CpZZrCl,] reacted with Li,[tmm(tmeda)lr3I to give 1, which
was obtained as deep red crystals in 45 YOyield. An X-ray struc-
Cl,C3,C2 planes is only 33.0(9)"; the terminal CH, group is
bent out of the Cl,C3,C2 plane by 7.8(5)".
The binding of the tmm ligand to the Zr atom is unusual. The
distances from the metal atom to C 1 and C 2 (227.7 and
225.8 pm, respectively) are very similar to those in Zralkyl complexes ([Cp,ZrMe,]: 228,""' [Cp,Zr(CH,),SiMe,]:
224 pm[7b1).The distance to the central atom C 3 (263.7 pm) is
typical for weak interactions (compare, for example, 259.7 pm
for C-2/3 in the butadiene complex [Cp,Zr(2,3-Me,C4H4)]rs1
and 263.3-269.2 pm in the q3-fluorenyl derivative
[CpZr(C,H4CMe,C,,H,)CI]r91); no direct interaction exists between C 4 and the Zr center (Zr ' " C 4 distance = 388 pm).
Thus, q 3 coordination is observed in 1. Finally, the long C 3-C4
bond (137.6(9) pm) shows that the delocalization of the K electrons of the tmm dianion is to a certain extent retained in the
complex.
The zirconocene fragment in 1 possesses three valence orbitals
with two valence electrons.["] It is therefore able to form two
strong CJ bonds with C 1 and C 2 of the tmm ligand, as in dialkyl
derivatives [Cp,ZrR,]. If the tmm ligand were not bent out of
plane, the acceptor orbital of the [CprZr] fragment would be
unable to overlap with the TC electron pair of the tmm ligand.
Only through the observed folding is a CJ interaction with C 3
possible. This phenomenon has been discussed previously for
enedithiolato complexes ([Cp,M(S,C,R,)] where M = Ti, Mo,
W) ,[lo]and is likewise observed for the analogous zircocenes
with butadiene['] and enediolato ligands.['ll The bonding in 1
may be represented according to the valence-bond method by
the resonance structures A and B (Scheme 1 ) .
B
A
[CpTZr(tmm)] 1
Scheme 1.
ture analysis shows 1 to be a bent metallocene with a side-bound
tmm unit (Fig. l).[41The angle between the CI,Zr,C2 and
Fig. 1. Crybtal structure of 1. Metallocene angle 136.9(4)"; Zr-C(10... 14) 254.1,
Zr-C(20 ' . 24) 256.3 pm (average); Zr-C1 227.7(6). Zr-C2 225.8(7), Zr-C3
263 7(7). CI-C3 149(1). C2-C3 151(1), C3-C4 137.6(9) pm; Cl-Zr-C2 66.7(3)', ZrC1-C3 86.1(4). Zr-C2-C3 86.4(4). Cl-C3-C2 112.2(6), CI-C3-C4 123.4(9), C2-C3C4 123.7(9)
In the NMR spectrum, the Cp* rings in 1 are equivalent, even
at low temperatures ('H NMR: -90 "C, 500 MHz; I3C NMR:
-9O"C, 125.7 MHz). Thus, in solution, the energy barrier for
the inversion of the [Zr(tmm)] moiety can only be small
(0 I
AG * < ca. 30 kJ mol- I ) . There is no evidence of high-amplitude motion or disorder of the tmm ligand in the solid state;
there are no short distances between the terminal methylene
group and neighboring molecules.r'21
Upon heating, 1 decomposed with cleavage of isobutene. Protonolysis with methanol and phenol generated [CpzZr(OR),]
(R = Mer131or Ph[l4I) and isobutene; no intermediates were
detectable by NMR spectroscopy. 2-Butyne and 2,3-dimethylbutadiene did not react with 1. On the other hand. insertions
into polar double bonds were successful. Thus, methyl formate
and tert-butyl isocyanate react with 1 at 0 ° C to form the sixmembered ring complexes 2 and 3, respectively; similar behavior was found with butadiene complexes.[' On warming. the
azaenolato complex 3 with an unconjugated K electron system
rearranged quantitatively to give the conjugated isomer 4.
'
[*] Prof. Dr. G. E. Herberich, Dr. C. Kreuder, Dr. U. Englert
Institut fur Anorganische Chemie der Technischen Hochschule
Professor-Pirlet Strdsse, D-52056 Aachen (FRG)
Telefax: Int. code + (24118888-288
Anjiex
Chem. In/. Ed. Engl. 1994, 33, No. 23/24
2
$7 VCH Vcrlagsgesellsrhufr mbH. 0-69451 Weinhrim, 1994
3
0570-0833/94i2323-2465 $ 1(1.00+ .25:0
4
2465
COMMUNICATIONS
At 0 "C, 1 reacted with tert-butyl isonitrile in a double insertion reaction to
yield the symmetric diiminoacyl complex
5. A similar reaction is known for
the cyclobutene complex [Cp,Zr(PMe,)(qz-C4H6)],'t61 whilst the 1-sila-3-zirconacyclobutane [Cp,Zr(CH,),SiMe,] undergoes two insertion reactions with C - C
coupling of two tBuNC molecules.['71
%.
cP;zy>
N
%
Experimental Procedure
1: A cooled suspension of [CpTZrCI,] (32.4 g. 0.75 mmol) in T H F (0.6L) and
hexane (0.6 L) was treated portionwise at -80°C with Li,[tmm(tmeda),] (13.8 g.
75 mmol) [ 3 ] .The mixture was warmed slowly (18 h) to 2 0 ° C volatiles were removed in vacuo. and the residue extracted portionwise with hexane (ca. 0.3 L) until
the extracts remained colorless. The solution was again evaporated to dryness (finally under high vacuum), and the residue taken up in hexane (0.15 L). The resulting
suspension was filtered through sea sand to remove insoluble solid material. Crystallization at -30 C gave 1 (14.1 g, 45%) as dark red rods [18]; m.p. 105 'C
(decomp.); MS:m!z(%): 414(32, M ' ) . 359(300, CptZr - H); 'H NMR(C,D,):
6 = 5.24 (quin, CH,=), 1.60 (t, 2ZrCH,, 4J= 1.5 Hz), 1.76 (s. 2Cp*); "C N M R :
6 =136.9 (s. C C , ) , 107.0 (tquin. 154, 6.5 Hz. CH,=). 56.0 (tm, 133 Hz. ZrCH,),
Cp*. 117.5 (s). 10.9 (9, 126 Hz)
2 : A solution of 1 (1.27g) in hexane (50mL) was treated at O'C with HC0,Me
(176 mg). After 2 h, all volatiles were carefully removed in vacuo. Crystallization
from hexane at -3O'C gave 2 (1.09g. 78%) as orange crystals [IX]; m.p. 110MeOH), 287 (100. Cp*Zr(OMe):): ' H N M R
120'C: MS: n ; z ("/a): 442 (13. M
(C,D,): 6 = 5.19 (dd, 'J(Sa.6) = 8.6, 'J(Sb.6) = 3.3 Hz. 6-H). 5.04 (t.
'J(AB) = 2.8 Hz. H4). 4.66 (dm, 2J(AB) = 3.2 Hz. H,) (protons of 4-CH2=
designated as H,, and H8). 3.27 (s, OMe), 2.55 (ddm, 'J(5a,Sb) =12.5.
'J(Sb.6) = 3.3 Hz, 5-HJ. 2.26 (ddm. 'J(Sa,Sb) = 12.5. '.J(Sa,6) = 8.6 Hz, 5-H,),
2.18 (dm. 2J(3a,3b) =11.0Hz. 3-H,), 1.84 and 1.83 (s, Cp*), 1.09 (dm,
'J(3a.3b) = 11.0 Hz. 3-H,j: "C N M R : 6 =154.0 (s, C=CH,). 107.0 (t, 153 Hz,
C H , = ) . 105.1 (d, 164Hz, OCH). 54.0 (qd. 140. 4Hz. OMe), 50.0 and 47.8 (1.
124Hz. CH,), Cp*: 119.34 (s), 119.32 (s), 11.52 and 11.47 (q, 126Hz).
3: A solution of 1 (2.60 g) in hexane (60 mL) was treated at 0°C with rBuNCO
(616 mg). After 12 h the precipitated yellow powder was filtered off. and the filtrate
concentrated. Further product crystallized at 30 C as orange platelets (total yield
1.YSg. 6 1 % ) [18]; decomp. 160-1XO'C; MS: m:z (%): 513 (67, M i ) , 379 (100.
.MH Cp*);'HNMR(C,D,):d = 4.99and4.70(dm,'J= 3.1 Hz,4-CH2=),3.12
(a. 2 x S-H). 1.76 (s. 2Cp*), 1.70 (s. 2 x 3-H). 1 54 (s, tBu): ',C N M R . 6 = 158.3 (s,
C=CH,).151.8(~.C=N).107.0(t,
154Hz.CH2=).53.0(t. 124Hz.CH2).49.7(t,
126 Hz. CH,). fBu: 52.X (s, CC,). 32.1 (q, 125 Hz, CMe,), Cp*: 120.2 (s), 11.3 (q.
125 Hz).
~
with 3 < 8 < 2 4 on the half Ewald sphere, 1862 symmetry independent with
1>3u(1) in the structure solution and refinement [6] for 232 parameters;
R = 0.041, R , = 0.047.
= u2(Fo),GOF =1.19; H atoms in structure factor calculation. Further details of the crystal structure investigation may be
obtained from the Fachinformationszentrum Karlsruhe, D-76344 EggensteinLeopoldshafen (FRG). upon quoting the depository number CSD-401223.
15) A. C. T. North. D. C. Phillips, E S. Mathews, A c f u Cr>stu//ogr.Sect. A 1968,
24, 351 -359.
[6] B. A. Frenz, The ENRAF-Nonius CAD4-SDP - a Real-Time Systemfor Concurrent X-Ray Daia CoNectionand Crystai Structure Determination (Coniputing
bz Crystallography (Eds.: H. Schenk, R. Olthof-Hazekamp, H. van Koningsveld. G. C . Bassi), Universitit Delft. 1978); SDP-PLUS. version 1.1. 1984,
and VAXSDP. version 2.2, 1985.
[7] a ) W. E. Hunter, D. C. Hrncir, R. V. Bynum, R. A. Pentilla, J. L. Atwood,
Organninrtu/lic$ 1983. 2, 750-755; b) W. R. Tikkanen, J. W. Egan, Jr., J. L.
Peterson, ihid. 1984, 3. 1646-1650.
[8] a) G . Erker. J. Wicher, K. Engel. F. Rosenfeldt, W. Dietrich, C. Kriiger, J. Am.
Chem. So<.1980, 102, 6344-6346; b) G. Erker. C. Kruger, G. Miiller, Adv.
Orgunomel. Chenz. 1985,24,1-39: c ) H. VdSuda, A. Nakamura, Angeu.. Chem.
1987. 99. 745-764; Angew. Chem. I n f . Ed. Engl. 1987, 26, 723-742.
[Y] G. M. Diamond. M. L. H. Green, P. Mountford. N. A. Popham, A. N.
Chernega, J. Chem. Soc. Chem. Commun. 1994, 103-105.
[lo] J. W. Lauher. R. Hoffmann, J Am. Chem. Sor. 1976, 98, 1729-1742.
[ l l ] P. Hofmann. M. Frede, P. Stauffert. W. Lasser, U. Thewalt, Angew. Chem.
1985, 97, 693-694; Angew. Chem. Inf. Ed. Engl. 1985,24, 712-713.
1121 Shortest contact from the terminal methylene group to its nearest neighbor ca.
270 pm. An inversion is not possible with the given packing of the molecules,
since the distance between the terminal methylene group and its nearest neighbor would have to shorten to < 170 pm in order to achieve planarity in the
[Zr(tmm)] ring.
[13] J. M. Atkinson, P. B. Brindley, J Organomel. Clzem. 1991, 411, 131-137.
[14] L. E. Schock. T. J. Marks, J Am. C1iri.n.Sac. 1988, ff0,7701-7715.
[15] a) H. Yasuda. T. Okamoto, Y Matsuoka, A. Nakamura, Y Kai, N. Kanehisa.
N . Kasai, OrgonomefaNics 1989, 8, 1139-1152: b) A. Nakamura, J
Organoinet. Chem. 1990, 400, 35-48, and references therein
[16] R. A. Fisher, S. L. Buchwald. Organometallics 1990, 9, 871-873.
1171 E J. Berg. J. L. Peterson. Organometallics 1991, 10, 1599-1607.
[I81 Correct C,H analysis.
~
~
4: Heating of 3 in toluene for I2 h at 60'C generated 4. The toluene was replaced
with hexane. Further workup as described for 3 afforded 4 as yellow platelets (total
yield 60%) [IX]; in.p. 67-75 C: ' H N M R (C,D,): 6 = 6.21 (q, ' J = 1.0 Hz, 5-H),
2.00 (dm. 4 J = 1 . 0 Hz, 4-Me), 1.75 (s. 2Cp*), 1.58 (s, tBu), 1.33 (s, 2 x 3 - H ) ;
" C N M R : 6 ~ 1 5 9 . (s,
2 C'C,), 148.8 (s. C=N). 129.1 (d. 156 Hz, CH=), 51.5 (t.
123 Hz. CH,). 32.1 (q, 125 Hz. 4-Me), rBu: 52.7 (s. CC,), 31.8 (4, 125 Hz. CMr,),
Cp*: 119.7 (s). 11.3 (q, 127 Hz).
5 : A solution of I (0 51 g) in hexane (30 mL) was treated at 0°C with tBuNC
(200 mgj. After 2 h the mixture was filtered through sea sand. Concentration of the
filtrate to cd. 10 mL gave, after cooling to - 3 0 ' C , 5 (240 mg, 35%) as an ochre-colored powder, which decomposed slowly at room temperature; MS'm!i(%): 497
( M i - fBuNC), 360 (100, CpfZr'); ' H N M R (C,D,): d = 4.88 (s. 4-CH,=). 3.36
(5.3-;5-CH2), 1.8O(s,2Cp*). 1.48(s,ZtBu): "C{'H) N M R : d = 230.3(Zr-C=N),
148.3 (CC,). 109.0 (CHI=). 58.7 (CH,). tBu. 47.5, 32.1, Cp*: 115.9. 12.7.
Received: June 9. 1994 IZ7022IEJ
German version: Angew. Chem., 1994, 106, 2589
[l] a) M. D. Jones, R. D. W. Kernmitt, Adv. Organomct.Chem. 1987.27,279-309;
b) B. Trost. Angew. Chem. 1986,98. 1-22; Angew. Chem. I n t . Ed. Engl. 1986,
25. 1-20: c) G. E. Herberich. T. P Spaniol, J. Chem. So<. Dalton Trans. 1993,
2471 -2476, and references therein.
[2] a) J. M. Mayer. C . J. Curtis. J. E. Bercaw, J Am. C'l7em. SOC.1983, 105, 2651 2660: b) G. C. Bazan. G. Rodriguez. B. P. Cieary. ;hid. 1994, f f6,21 77- 21 78.
[3] J. Kleiu. A. Medlik, J Chem. Soc. Cl7em. Commun. 1973,275-276. Theisolated
solids have the approximate formula Li2[tmm(tmeda)].
[4] Crystal structure analysis: ENRAF-Nonius CAD4 diffractometer; Mo,. radiation, graphite monochromator: empirical absorption correction (PSI [ S ] ) ;
intensity data with 0) scan collected at 253 K: dark red parallelepiped,
0.3 x 0.3 x 0.2 mni, monoclinic. space group P2,;c (no. 14); a = 1093.7(8).
h = Y61.0(4), L' = 2060(1) pm. [I = Y2.3(6) , I/ = 2.164(4) nm',
Z = 4,
pCrad
= 1.28 gem-'. p(Mo,,) = 5.02 c m - ' . F(OO0)= XX0: 6879 reflections
2466
((2
VCH Ver/rg.~~e~r//srhu/t
mbH, 0-69421 Weinhcim, 1994
Total Synthesis of Soraphen A,,
Stephan Abel, Dominik Faber, Ottmar Hiiter, and
Bernd Giese*
In 1986 a new class of 18-membered macrolides called the
soraphens were isolated by H. Reichenbach, G. Hofle et al. as
metabolites of the microorganisms Sorangium cellulosum."' The
parent compound, soraphen A,, (1 a), contains ten stereogenic
centers, and the methyl, methoxy, and hydroxy groups of the
tetrahydropyran ring occupy axial positions.r21 Due to this
chemical structure as well as its antifungal activity, the novel
natural product soraphen A,, is an interesting target for synthes ~ s . ' Herein
~]
we report the first total synthesis of soraphen 1 a
and 2-norsoraphen 1 b. The retrosynthetic analysis of 1 leads to
compounds 2 and 3, which are both available from D-glucose
(Scheme 1). These building blocks were connected by a Julia
olefination (6 13 -14) as well as a subsequent lactonization
(16 -1 b). Further key steps of the synthesis involve stereoselective chain elongation (10 -11) and methylation of 2-norsoraphen 1 b resulting in soraphen (1 a).
The synthesis of 6, a silylated derivative of 2, was accomplished by converting the dideoxysugar 4[41into the dithiane 5
and elongating the chain with Corey-Seebach methodology
+
[*] Prof. Dr. B. Giese, Dr. S. Abel. D. Faber, Dr. 0. Huter
Departement Chemie der Universitat
St. Johanns-Ring 19, CH-4056 Basel (Switzerland)
Teiefax: Int. code + (61)3226017
[**I This work was supported by Ciba-Geigy. We thank Prof. M. Zehnder and M.
Neuburger for performing the crystal structure analysis.
OS70-0833/94/2323-2466$10.00 + ,2510
Angew. Chem. Int. Ed. EnKl. 1994, 33, No. 23/24
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bonding, mode, bis, pentamethylcyclopentadienyl, zirconium, new, ligand, trimethylenemethane
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