6808
J. Am. Chem. SOC. 1982, 104, 6808-6809
83487-27-8; Re(N-r-Bu),Me,, 83487-28-9; R ~ ( N - ~ - B U ) ~ ( C H , P ~ ) , , 83487-29-0; R ~ ( N - ~ - B U ) ~ ( C H , S ~ M ~83487-30-3; ,),, Re(N-t-Bu),CI,, 83487-31-4; R ~ ( N - ~ - B u ) ~ N83487-32-5; ~,, Re(N-t-Bu),(CHSiMe,)83487-34-7; (CH2SiMe,), 83487-33-6; Re(N-r-Bu),(CHPh)(CH,Ph), [Re(C-t-Bu)(CH-t-Bu)(NH2-f-Bu)Clz]2, 835 10-97-8; Re(C-t-Bu)(NHt-Bu)(CH2-t-Bu)CI2(Py), 83510-98-9; Re(C-t-Bu)(CH-t-Bu)(TMEDA)I,, 83510-99-0; R~(C-~-BU)(CH-~-BU)(O-~-BU)~, 83487-35-8; Re(CCMe3(CHCMe3)Py212,835 1 1-00-6.
Reaction of Tungsten(V1) Alkylidyne Complexes with Acetylenes To Give Tungstenacyclobutadiene and Tungsten Cyclopentadienyl Complexes Steven F. Pedersen,Ia Richard R. Schrock,*la Melvyn Rowen Churchill,*Ib and Harvey J. WassermanIb Department of Chemistry Massachusetts Institute of Technology Cambridge, Massachusetts 02139 and Department of Chemistry State University of New York Buffalo, New York 14214 Received July 29, 1982
Figure 1. ORTEP-11 diagram (30% ellipsoids) of W[C-t-BuCMeCMeICI, with hydrogen atoms omitted. Scheme I W(CEt)(OBut)3
+
EtCECEt
-
red
1
(slow)
We have reported that W(C-t-Bu)(O-t-Bu), will catalytically metathesize dialkylacetylenes a t a high rate, presumably by forming unstable tungstenacyclobutadiene intermediatesG2On the other hand, while complexes such as W(C-~-BU)(CH~-~-BU),,~ O=W\OBut W(C-t-Bu)(dme)C13,4and [NEt,] [W(C-t-Bu)Cl4I2will react with d’ 0 +EtCECEt acetylenes, they do not metathesize them catalytically. We report But ( c olorless) here that W(C-t-Bu)(dme)Cl, reacts with dialkylacetylenes to give a stable tungstenacyclobutadiene complex, that tungstenathe axis of the acetylene ligand in W(q5-C5Me4-t-Bu)(MeC= cyclobutadiene complexes containing certain alkoxide ligands (but CMe)C12lies parallel to the plane of the cyclopentadienyl ligand, not three tert-butoxide ligands) are also stable, and that cycloand the acetylene carbon-carbon bond length is lengthened pentadienyl complexes are formed in the presence of excess diconsiderably as a result of its strong bond to the metal. Therefore, alkylacetylene, even (slowly) in the active alkyne metathesis species are also we propose that the “[W(C-t-B~)(alkyne)~Cl~]~” system. substituted cyclopentadienyl complexes, [W(qS-C5R4-t-B~)C14]2. Excess 3-hexyne reacts with [NEt4][W(C-t-Bu)Cl,] in diand [W(q5-C5R4-tMost likely W(q5-CSR4-t-Bu)(RC=CR)C12 chloromethane to give a pentane-soluble paramagnetic red complex Bu)C14] form via disproportionation of some intermediate with the empirical formula W(C-t-Bu)(CH3CH2C= tungsten(1V) complex, possibly “W(qS-C5R4-t-Bu)C1,”as shown CCH2CH3)3C12in -50% yield. 2-Butyne reacts more rapidly in eq 1 and 2. with [NEt,] [W(C-t-Bu)C14]to give an analogous ether-soluble W(C-t-Bu)(dme)Cl, + 2RC=CR “W(q5-C5R4-t-B~)Cl3” species. Both can be obtained more straightforwardly by reacting (1) an e x w of the alkyne with W(C-t-B~)(dme)Cl~.~ In this reaction a less soluble, paramagnetic, orange complex with the empirical O.SRC*R “W(qS-CSR4-t-B~)C13” formula W ( C - t - B ~ ) ( a l k y n e ) ~ Calso l ~ ~forms in -50% yield by 0.5W(q5-C5R4-t-Bu)(RC~CR)Cl2 weight. A molecular weight study of “W(C-t-Bu)(EtC= CEt),C14” in dichloromethane at 0 ‘C (by differential vapor 0.25[W(q5-C5R4-t-Bu)C14]2 (2) pressure measurement) showed it to be a dimer. Addition of only 1 equiv of 3-hexyne or 2-butyne to W(C-tAn X-ray structural study6 of “W(C-~-BU)(M~C=CM~)~C~~” Bu)(dme)C13yields violet diamagnetic complexes with the formula shows it to be W(q5-C5Me4-t-Bu)(MeC=CMe)C1,, a species that W(C-t-Bu)(RC=CR)C13.8 13C NMR studies suggested that is closely related to the diamagnetic Ta(II1) derivatives, Tathese species are tungstenacyclobutadiene complexe~.~ An X-ray (qs-CSMe5) (alkyne) C12.7 As in Ta (qS-CsMe5)(PhCECPh) C12,’ structural studylo of W(C-t-Bu)(MeC=CMe)Cl, confirmed this proposal (Figure 1). The molecule is nearly a trigonal bipyramid (1) (a) Massachusetts Institute of Technology; (b) State University of with axial chloride ligands (LCl(l)-W-C1(2) = 166.12 (9)’) and
+< -
-
New York at Buffalo. (2) (a) Wengrovius, J. H.; Sancho, J.; Schrock, R. R. J. Am. Chem. SOC. 1981, 103, 3932. (b) Sancho, J.; Schrock, R. R. J. Mol. Coral. 1982, 15, 7 5 . (3) Clark, D. N.; Schrock, R. R. J. Am. Chem. SOC.1978, 100, 6774. (4) Purple W(C-f-Bu)(dme)CI, is prepared by treating W(C-t-Bu)( c H 2 - t - B ~ in ) ~ a mixture of pentane, ether, and 1 equiv of 1,2-dimethoxyethane (dme) with 3 equiv of HCI: Schrock, R. R.; Clark, D. N.; Sancho, J.; Wengrovius, J. H.; Rocklage, S . M.; Pedersen, S . F. Organometallics 1982, in press. (5) W(C-f-Bu)(CH3CH2C=CCH2CH3),Cl4. Anal. Calcd for WC1,H2&I4: C, 36.52; H, 5.23; CI, 25.37. Found: C, 36.66; H, 5.28; CI, 26.17. MW (differential vapor pressure, CH2C12,0 “C); Calcd: 1118. Found 1141 at 3 X lo-, M. (6) W(?5-C5Me4-t-Bu)(MeC=CMe)C12 crystallizes in the monoclinic space group P 2 1 / cwith a = 8.41 1 (1) A, b = 26.639 (5) A, c = 8.971 (1) A, = 114.320 (l)’, and p(calcd) = 1.89 g for Z = 4 and M,522.2. The final RF = 3.2% for 181 variables refined against all 2244 absorption corrected data. This structure will be reported in its entirety by M.R.C. and H.J.W. (7) Smith, G.; Schrock, R. R.; Churchill, M. R.; Youngs, W. J. Inorg. Chem. 1981, 20, 387.
+
(8) W(C-t-Bu)(CH3CH2C=CCHzCH3)CI,. Anal. Calcd for WClIHIOC13:C, 29.93; H, 4.34; C1, 24.09. Found: C, 30.23; H, 4.50; CI, 24.39. (9) ”C(lHJNMR spectrum of W(C-f-Bu)(CH3C=CCH3)C13 (CDzCI2) 6 267.5 and 263.4 (CJ, 150.7 (C&, 44.3 (CCMe,), 29.5 (CCMe,), 25.6 and 17.2 ( C M e ) . 13C(1HJNMR spectrum of W(C-t-Bu)(CH3CH2C= CCH2CH3)C13(C,D6): 6 267.6 and 266.7 (CJ, 150.3 (C,) 43.8 (CCMe,), 32.0 and 24.5 (CCH,CH,), 29.8 (CCMe,), 14.3 and 11.9 (CCH,CH,). (10) W[C-f-BuCMeCMe]CI, crystallizes in the centrosymmetric monoclinic space group P 2 , / c with a = 10.271 2) .&,b = 10.113 (2) .&, c = 12.721 (3) A, = 96.10 (2)”, V = 1313.8 (5) and p(calcd) = 2.09 g cmd for Z = 4 and M,413.4. Diffraction data were collected via a coupled 28-8 scan technique” using a Syntex P2, diffractometer and were corrected for absorption. All non-hydrogen atoms were located and refined, the final discrepancy factors being RF = 4.6% and RwF= 4.4% for all 2327 independent reflections (none rejected) with 4O 5 28 5 50.0”. (1 1) Churchill, M. R.; Lashewycz, R. A,; Rotella, F. J. Inorg. Chem. 1977, 16, 265.
a3,
0002-786318211504-6808$01.25/0 0 1982 American Chemical Society
J. Am. Chem. SOC.1982, 104, 6809-681 1
6809
of a tungstenacyclobutadiene ring or further reaction to give an essentially planar WC, ring lying in the equatorial plane. The (ultimately) cyclopentadienyl complexes will likely prove to be substituent carbon atoms (C(2), C(8), C(9)) and Cl(3) also lie very sensitive to the structure of the complex and (especially) the in the equatorial plane. The W-C, bond lengths are equal and steric and electronic properties of the ligands. slightly shorter than the W=C, double bond distance of 1.942 (9) 8, found in W(C-~-BU)(CH-~-BU)(CH~-~-BU)(~~~~).'~ Acknowledgment. We thank the National Science Foundation Carbon-carbon distances within the four-membered ring are infor support (Grants CHE 80-23448 to M.R.C. and 82-21282 to termediate between those expected for pure double and pure single R.R.S.) and the Dow Central Research Department for a felbonds but are slightly closer to the latter. The three most surlowship to S.F.P. prising features are the large C,-Cp-C, angle (1 18.9 (8)O), the Registry No. [NEt,] [W (C-t-Bu) Cl,] , 782 5 1- 20-4; W (C-t- Bu) (dme)short W-C, distance (far shorter than the W-C, single bond length of 2.258 (8) A in W(C-t-Bu)(CH-t-Bu)(CH,-t-Bu)-C13, 83542-12-5; W($-C5Et4-t-Bu)(EtC&Et)C1,, 8351 1-01-7; W($C 5 M e 4 - t - B u ) ( M ~ C M e ) C l 2 83511-02-8; , [W(?5-C5Et4-t-B~)C14]2, (dmpe)',), and the large W-C(l)-C(Z) and W-C(7)-C(8) angles 8351 1-03-9; [W($-C5Me4-t-B~)C14]2,835 11-04-0; W(C-t-BuCEtCEt)(149.9 (7) and 156.6 (7)O, respectively). These results contrast CI,, 83487-36-9; W(C-t-BuCMeCMe)CI,, 83487-37-0; W [C-t-BuCsharply with those for Rh(C3Ph3)C12(PMezPh)213 and [IrMeCMe](O-r-Bu)CI,, 83487-38-1; W[C-t-BuCMeCMeI(0-t-Bu)(C3Ph,)(CO)(C1)(PMe3)2]+14 in which little, if any, multiple (OCMe2CMe20), 83487-39-2; W(CEt)(O-t-Bu),, 82228-88-4; Wmetal-carbon bond character is present, and the metallacyclic unit (C,Et3)(0-t-Bu)(OCMe,CMe,O), 83487-40-5; W(q5-CsEts)(O-t-Bu)02, is compressed along the C,-Cd direction. (The C,-C,, distance 8351 1-05-1; 3-hexyne, 928-49-4; 2-butyne, 503-17-3; tert-butyl alcohol, 75-65-0; pinacol, 76-09-5; tetramethylethylene, 563-79- 1. in W[C-t-BuCMeCMe]Cl, is 2.525 (12) 8, but in RhC1,(PMe,Ph),(C3Ph3)I3 it is only 2.156 (6) A.) Supplementary Material Available: Listings of positional paW[C-t-BuCMeCMe]Cl, reacts with 1 equiv of tert-Butyl alrameters and observed and calculated structure factors (14 pages). cohol in the presence of NEt, to give W[C-t-BuCMeCMeI(0Ordering information is given on any current masthead page. t-Bu)Cl2.IS Addition of a second equivalent of LiO-t-Bu to W [C-t-BuCMeCMe](O-t-Bu)Cl, produces only half an equivalent of W(CR)(O-t-Bu), where R is t-Bu or Me. Surprisingly, therefore, W [C-t-BuCMeCMe](0-t-Bu)(OCMe2CMe20)can be Protiodesilylation Reactions of Simple prepared16 and is stable toward cleavage of the WC3 ring or 0-Hydroxysilanes (and a-Hydroxysilanes). formation of the p-tert-butyl-substituted isomer. Furthermore, Homo-Brook Rearrangements' addition of 1 equiv of pinacol to a mixture of W(CEt)(O-t-Bu), Paul F. Hudrlik,* Anne M. Hudrlik, and Ashok K. Kulkarni and 3-hexyne yields an analogous complex, W(C,Et,)(O-tBu)(OCMe2CMe20)" (Scheme I). The pinacolate complexes Department of Chemistry, Howard University will not metathesize 3-heptyne. At least one of the reasons is that Washington, DC 20059 W(C3Et3)(O-t-Bu)(OCMe2CMe20) reacts with an excess of Received July 1 , 1982 3-hexyne to give colorless W(~S-CSEt5)(O-t-Bu)Oz18 and tetramethylethylene quantitatively, possibly via intermediate, unstable @-Hydroxysilanes have been of considerable interest as preW(qS-CSEt5)(0CMe2CMe20) (0-t-Bu) .I9 cursors to geometrically defined olefins and heteroatom-substituted The question that remained was why alkyne metathesis using olefins because of their stereospecific olefin-forming p-elimination W(CR)(O-t-Bu), catalysts eventually ceases? We know that reactions, and therefore a number of methods to prepare diaW2(0-t-Bu), cannot be formed since it reacts with dialkylstereomerically pure P-hydroxysilanes have been developed.2 We acetylenes to give W(CR)(O-f-Bu)J.21 A simpler 'active" system have recently become interested in the possibility that the R3Si consisting of a mixture of W(CEt)(O-t-Bu), and excess 3-hexyne group in a P-hydroxysilane could be replaced by H (protiowas allowed to "decompose" to give an as yet unidentified diadesilylation) or by another substituent, thus enabling P-hydroxmagnetic red complex with the empirical composition Wysilanes to serve as precursors to saturated organic systems. Here (CEt),(O-t-Bu), (by 'H and I3C NMR). This red species slowly we report that simple unactivated P-hydroxysilanes can undergo (days) also decomposed to give colorless W($-CSEts)(O-t-Bu)Oz, protiodesilylation when treated with base in aqueous dimethyl the only significant diamagnetic product. sulfoxide (Me,SO), that unactivated a-hydroxysilanes also undergo We conclude from these results that tungstenacyclobutadiene protiodesilylation (essentially a Brook rearrangement followed by complexes are the intermediates in the alkyne metathesis reaction hydrolysis) under these conditions, and that both reactions take and that they can react with additional alkyne to yield cycloplace with complete retention of stereochemistry at carbon. pentadienyl complexes. We can also now expect that cleavage Cleavage of unactivated carbonsilicon bonds is ordinarily quite difficult. Our earlier work with a,@dihydroxysilanes3suggested (12) Churchill, M. R.; Youngs, W. J. Inorg. Chem. 1979, 18, 2454. to us that base-induced protiodesilylation reactions should be (13) Frisch, P. D.; Khare, G. P. Inorg. Chem. 1979, 18, 781. facilitated by the presence of a P hydroxyl as shown in the (14) Tuggle, R. M.; Weaver, D. L. J . Am. Chem. SOC.1970, 92, 5523. mechanistic rationale in Scheme I. Simple (unactivated) P-hy(15) The rert-butoxide ligand is believed to be in the equatorial position droxysilanes normally undergo facile p-elimination reactions when in W[C-t-BuCMeCMe](O-t-Bu)C12. Anal. Calcd for WC,,H2,CI20: C, 34.61; H, 5.36. Found, C, 34.56; H, 5.41. 'H NMR (C6D6) 6 3.08 (s, 3, treated with base under aprotic conditions (e.& KH/THF). (The CMe), 2.16 (s, 3, CMe), 1.75 (s, 9,O-t-Bu), 1.39 (s, 9, C-f-Bu); '3C(1H)NMR reaction is considerably accelerated by the presence of anion(C6D6) 6 265.6 and 259.1 (Jcw = 93, 116 Hz, Ca), 134.2 (Cp), 87.9 (OCMe,), 42.7 (CCMe,), 31.1 and 29.6 (OCMe, and CCMe,), 24.3 and 12.4 (CMe). (16) I3C{'H)NMR (C6D6) 6 232.1 and 225.2 (Jcw = 122, 134 HZ, CJ, 128.9 (Cp), 88.3 (02C2Me4),75.9 (OCMe,), 40.4 (CCMe,), 31.9, 31.7 and 27.6 (OCMe,, CCMe, and OZC2Me4, not assignable), 22.0 and 13.0 (CMe). Molecular ion found at mass saectrum. -. 496 in ~~~. - r - - -- ---(17) "CI'H) NMR (c&) 6 226.5 (C,CH2CH,), 132.9 (CpCH2CH3), 75.6 (OCMe,), 31.8 (OCMe,), 29.3 (CCH2CH,), 27.6 (02C2Me4).23.2 (CCH2CH,), 16.0 and 12.9 (CCH,CH,). Molecular ion found at 496 in mass ~. spectrum. (18) W(t15-C~Et5)(O-t-Bu)Oz.Anal. Calcd for WCI9H3,O3: C, 46.17; H, 6.93. Found: C, 45.78; H, 6.80. Mass spectrum molecular ion at 494. "CI'HJ NMR (C6D6) 6 123.6 (t15-C5Et5),79.7 (OCMe,), 30.3 (OCMe,), 19.3 (CHICH,), 15.7 (CHzCH3). (19) This type of decomposition of glycolates was proposed as the way in which tungsten(1V) halide complexes converted glycols into olefins.20 (20) (a) Sharpless, K. B.; Flood,T. C. J . Chem. Soc., Chem. Comm. 1972, 370. (b) Sharpless, K. B.; Umbreit, M. A,; Nick, M. T.;Flood, T.C. J. Am. Chem. SOC.1972, 94, 6538. (21) Schrock, R. R.; Listemann, M. L.; Sturgeoff, L. G. J . Am. Chem. Soc. 1982, 104, 4291. ~~~
~
~
~~~~
~~
~~
0002-7863/82/1504-6809$01.25/0
(1) A portion of this work was presented at the 15th Middle Atlantic Regional Meeting of the American Chemical Society, Washington, DC, Jan 1981; Abstr 306. (2) (a) Hudrlik, P. F.; Peterson, D. J . Am. Chem. SOC.1975, 97, 1464-1468. (b) Hudrlik, P. F.; Peterson, D.; Rona, R. J. J . Org. Chem. 1975, 40, 2263-2264. (c) Utimoto, K.; Obayashi, M.; Nozaki, H. Ibid. 1976, 41, 2940-2941. (d) Hudrlik, P. F.; Hudrlik, A. M.; Rona, R. J.; Misra, R. N.; Withers, G. P. J . Am. Chem. SOC.1977, 99, 1993-1996. (e) Sato, T.; Abe, T.; Kuwajima, I. Tetrahedron Letf. 1978, 259-262. (f) Yamamoto, K.; Tomo, Y.; Suzuki, S . Ibid. 1980, 21, 2861-2864. (9) Hudrlik, P. F.; Hudrlik, A. M.; Misra, R. N.; Peterson, D.; Withers, G. P.; Kulkarni, A. K. J . Org. Chem. 1980,45,4444-4448. (h) Hudrlik, P. F.; Hudrlik, A. M.; Nagendrappa, G.; Yimenu, T.; Zellers, E. T.;Chin, E. J . Am. Chem. SOC.1980, 102, 68946896. (i) Dav,is, A. P.; Hughes, G. J.; Lowndes, P. R.; Robbins, C. M.; Thomas, E. J.; Whitham, G. H. J . Chem. Soc., Perkin Trans. I 1981, 1934-1941. ('j) Hudrlik, P. F.; Kulkarni, A. K. J . Am. Chem. Sot. 1981, 103, 6251-6253. (3) (a) Hudrlik, P. F.; Schwartz, R. H.; Kulkarni, A. K. Tetrahedron Letf. 1979, 2233-2236. (b) Hudrlik, P. F.; Nagendrappa, G.; Kulkarni, A. K.; Hudrlik, A. M. Ibid. 1979, 2237-2240.
0 1982 American Chemical Society
