Vinylaminocarbenes of Group 6 Metals by Metathesis Reaction of 2

Feb 1, 1995 - Introduction. Heteroatom-stabilized group 6 metal carbene com- plexes have been widely used in organic synthesis in the last few years.l...
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Organometallics 1995, 14, 1429-1433

1429

Vinylaminocarbenes of Group 6 Metals by Metathesis Reaction of 2-Amino-l,3-butadienes.Reactivity toward Electron-Deficient Alkenes Jose Barluenga,” Fernando Aznar, and Alfred0 Martin Instituto Universitario de Quimica Organometalica “Enrique Moles”, Campus del Cristo, Universidad de Oviedo, 33071-Oviedo, Spain Received October 18, 1994@

A new method for the synthesis of chromium, molybdenum, and tungsten Fischer-type vinylaminocarbenes 3 by the metathesis reaction of 2-amino-1,3-butadienes and phenyloxycarbenes is reported. In addition, the reaction of 3 with electron-deficient alkenes to afford, after hydrolysis, the vinyl ketones 6 has been studied. In order to explain this behavior, a cyclopropanation process has been proposed, which is supported by the formation of the seven-membered ring 8 from diene 7. Introduction Heteroatom-stabilized group 6 metal carbene complexes have been widely used in organic synthesis in the last few years.l The first, widely developed process discovered involving these types of compounds has been the cyclopropanation of alkenes.2 Many examples of this reaction have been described using alkyl, aryl, and vinyl oxycarbenes of chromium, molybdenum, and tungsten. It is known that either the metal and/or the carbon substituent plays an important role in the reactivity of these complexes; thus, the mildest reaction conditions have been reported for carbenes containing either an alkenyl substituent3 or m~lybdenum.~ Although their potential has been ~ u t l i n e d aminocar,~ benes have been much less explored than the oxygen analogues.6 This might be due t o the lack of general methods for preparation of aminocarbenes, especially @

Abstract published in Advance ACS Abstracts, February 1,1995.

(1)For reviews on the synthetic applications of Fischer carbene

complexes, see: (a) Dotz, K. H.; Fischer, H.; Hofmann, P.; Kreissel, F. R.; Schubert, U.; Weiss, K. Transition Metal Carbene Complexes; Verlag Chemie: Deerfield Beach, FL, 1984. (b) Dotz, K. H. Angew. Chem., Int. Ed. Engl. 1984,23, 587. (c) Casey, C. P. React. Intermed. 1986,3. (d) Dotz, K. H. In Organometallics in Organic Synthesis: Aspects of a Modern Interdisciplinary Field; tom Dieck, H., de Meijere, A., Eds.; Springer-Verlag: Berlin, 1988. (e) Schore, N. E. Chem. Reu. 1988,88, 1081. (0Aduances in Metal Carbene Chemistry; Schubert, U., Ed.; Kluwer: Boston, MA, 1989. (g) Wulff, W. D. In Advances i n MetalOrganic Chemistry; Liebeskind, L. s.,Ed.; JAI Press: Greenwich, CT, 1989, Vol. 1.(h) Harrington, P. J. Transition Metals in Total Synthesis; Wiley: NewYork, 1990; pp 346-399. (i) Wulff, W. D. In Comprehensive Organic Synthesis; Trost, B. M., Fleming, I., Eds.; Pergamon Press: New York; 1991; Vol. 5. (2) For recent examples, see: (a) Brookhart, M.; Studabaker, W. B. Chem. Rev. 1987.87.411. (b) Wienand. A,: Reissie, H.-V. Tetrahedron Lett. 1988, 29, 2315. (c) Herndon, J. W.;’Tume< S. U. Tetrahedron Lett. 1989, 30, 4771. (d) Wienand, A.; Reissig, H.-U. Angew. Chem., Int. Ed. Engl. 1990,29, 1129. (e) Murray, C. K.; Yang, D. C.; Wulff, W. D. J . A m . Chem. SOC.1990,112,5660.(f) Soedberg, B. C.; Hegedus, L. S.; Sierra, M. A. J. Am. Chem. SOC.1990, 112, 4364. (g) Herndon, J. W.; Tumer, S. U. J . Org. Chem. 1991, 56, 286. (h) Hegedus, L. S.; Bates, R. W.; Soedberg, B. C. J . A m . Chem. SOC.1991, 113, 923. (i) Barluenga, J.;Tomas, M.; Ballesteros, A.; Santamaria, J.; Lopez-Ortiz, F. J. Chem. SOC.,Chem. Commun. 1994,321. (3) (a) Wulff, W. D.; Yang, D. C.; Murray, C. K. J . Am. Chem. SOC. 1988, 110, 2653. (b) Barluenga, J.; Aznar, F.; Martin, A.; GarciaGranda, S.; Salvad6, M. A.; Pertierra, P. J . Chem. SOC., Chem. Commun. 1993, 319. (c) Barluenga, J.; Aznar, F.; Valdes, C.; Martin, A.; Garcia-Granda, S.; Martin, E. J . Am. Chem. SOC.1993,115, 4403. (4) (a) Harvey, D. F.; Brown, M. F. Tetrahedron Lett. 1990,31,2529. (b) Harvey, D. F.; Lund, K. P. J . A m . Chem. SOC.1991, 113, 8916. (5)Anderson, B. A,; Wulff, W. D.; Powers, T. S.; Tribbit, S.; Rheingold, A. L. J . A m . Chem. SOC.1992, 114, 10784.

vinylamin~carbenes,~ and to their lower reactivity as compared with the oxygen-stabilized derivatives. In this regard, some benzannulation8 and [4 2 P 9 processes have been described for vinylaminocarbenes, while only two intermolecular cyclopropanation reactions involving chromium aminocarbenes have been reported, to the best of our knowledge.1° We wish to report in this paper a direct general entry into group 6 metal vinylaminocarbene complexes, which is the first one described for molybdenum derivatives, based on the metathesis reaction between 2-amino-1,3butadiene derivatives and Fischer oxycarbenes, as well as some examples showing the remarkable reactivity of those systems toward electron-deficient olefins; the behavior of molybdenum and tungsten derivatives is reported here for the first time.

+

Results and Discussion 2-Morpholino 1,3-dienes 1 react with methoxyphenyl complexes 2a-c, giving rise t o the vinylaminocarbenes 3, in quite good yields, and a-methoxystyrene 4 (Scheme 1,Table 1). It is accepted that the metathesis reaction 21 cycloaddition takes place through a formal [2 followed by ring opening of the metallacyclobutane intermediate I.ll Although the process is probably reversible at the microscopic level, the equilibrium is displaced toward the formation of amino derivatives due to the higher stability of aminocarbenes compared with alkoxycarbenes. In all cases variable amounts of 1,2-

+

(6) (a) Schwindt, M. A.; Miller, J. R.; Hegedus, L. S. J. Organomet. Chem. 1991, 413, 143. (b) Grotjahn, D. B.; Dotz, K. H. Synlett 1991, 381. (7) (a) Macomber, D. W.; Maudhukar, P.; Roger, R. D. Organometallics 1989, 8, 1275. (b) Baldoli, C.; Buttero, P. D.; Licandro, E.; Maiorana, S.; Papagni, A,; Zanotti-Gerosa, A. Synlett 1993, 935. ( 8 )(a) Yamashita, A. Tetrahedron Lett. 1986,27, 5915. (b) Dotz, K. H.; Erben, H.; Harms, K. J. Chem. SOC.,Chem. Commun. 1989, 629. (c) Dotz, K. H.; Grotjahn, D.; Harms, K. Angew. Chem., Int. Ed. Engl. 1989,28,1384. (d) DBtz, K. H.; Schafer, T.; Harms, K. Angew. Chem., Int. Ed. Engl. 1990,29, 176. (9) (a)Dijtz, K. H.; Noack, R.; Harms, K. Tetrahedron 1990,46,1235. (b) Anderson, B. A,; Wulff, W. D.; Powers, T. S.; Tribbitt. S.; Rheingold, A. L. J . Am. Chem. SOC.1992,114, 10784. ( c )Rahm, A.; Wulff, W. D. Organometallics 1993, 12, 597. (IO) Wienand, A.; Reissig, H. Organometallics 1990, 9, 3133. (b) Sierra, M. A.; Soderberg, B.; Lander, P. A.; Hegedus, L. S. Organometallics 1993, 12, 3769. (11)Casey, C. P.; Tuinstra, H. E.; Saeman, M. C. J . A m . Chem. SOC. 1976, 98, 608.

0276-733319512314-1429$09.00/0 0 1995 American Chemical Society

1430 Organometallics, Vol. 14,No. 3, 1995

Barluenga et al. Scheme 2

Scheme 1 R2

' y OrJ. R'

M(C0k PhKOMo

1c

R2

l a CH3 CH20CH3 l b CH3 CH20TBDMS 1C CH2-CH2-CH2

2aM=Cr Ob M = MO 2cM=W

I

3

4

Table 1" entry

R'

ab bC

CH3 CH3 CH3 CH3 CH3 CH3

Cd

db eb fd g'

hC id

R2 CH20CH3 CHzOCH3 CH20CH3 CHzOTBDMS CH2OTBDMS CHzOTBDMS CH2CHzCH2 CH2CH2CH2 CH2CH2CH2

M

t(h)

Cr Mo W Cr MO W Cr Mo W

6 4 38 5.5 1 40

3 2.5 12

3(%)

riz

3 t

75 57 64 65 35 18 69 55 46

Tol, 111OC

5

r

Yields are based on amino diene 1. Reactions were performed in sealed tubes. In toluene at 110 "C. In tetrahydrofuran at 66 OC. In tetrahydrofuran at 100 OC.

Table 2" a b

3a

C02CH3 COzCH3 COzCH3 CN COCH3 C02CH3

1.5 1 10 1 1 1

66 70 30 78

diphenyl-l,2-dimethoxyethane,resulting from the dimerization of carbene,12 could be detected in the reaction mixture as a byproduct; because of that, an excess (2070 mol %) of 2 was used in order to improve the yield by total consumption of the amino diene. As can be deduced from Table 1, tungsten methoxyphenyl carbene is less reactive in the metathesis process than the corresponding chromium and molybdenum derivatives (entries c, f, and i), and an increase in the temperature and/or the reaction time is required in order to take the reaction to completion. On the other hand, due to the greater tendency of molybdenum carbenes toward cyclopropanation, small amounts of cyclopropane derivatives ( 5 1 0 % ) can be isolated as a mixture of diastereoisomers in the case of reactions involving the molybdenum complex 2b. In the reaction of IC with complex 2a (see Scheme 2), the new carbene 3'g,13formed from 3g by loss of one CO ligand under the reaction conditions, could be isolated along with 3g. Compounds 3g and 3 g can be easily interconverted; thus, bubbling CO into a THF solution of 3'g leads quantitatively to 3g, while 3'g can be in turn formed in good yield by heating 3g to 66 "C (see Experimental Section). The availability of these new chromium, molybdenum, and tungsten aminocarbene complexes encouraged us to investigate their ability to cyclopropanate electrophilic olefins and the influence of the metal as well. Thus, the reaction of complexes 3 with electron-poor

olefins 5 in toluene at 110 "C yielded the new l-substituted 2-amino dienes III. Compounds 111 could not be isolated due to their instability toward aqueous media or chromatographic conditions (silica gel, hexane-ethyl acetate) required for purification, but they were identified on the basis of the NMR analysis of the crude reaction mixtures (for instance, in the reaction of the complex 3g and methyl acrylate, the most remarkable 13C NMR signals for III are those at 174.0, 95.9, 67.5, and 50.0 ppm, assigned to the ester, the 8-enamine, and the morpholine carbon atoms, respectively). In addition, the hydrolysis in Si02 of the reaction mixture affords the expected derivatives 6 (Scheme 3, Table 2). A plausible mechanism accounting for the formation of the amino diene 111 involves the formation of the donor-acceptor disubstituted cyclopropane 11, which is not stable under the reaction conditions14but undergoes cyclopropane ring opening to give III. As recorded in Table 2, the reaction yields are higher in the case of the chromium and molybdenum carbenes (entries a and b) than for the tungsten derivative (entry c), probably because of the higher M-CO energy of the latter that impedes the CO ligand dissociation necessary for the olefin-metal coordination.

(12)Casey, C. P.; Cesa, M. C. Organometallics 1982, 1, 87. (13)Barluenga, J.;Aznar, F.; Martin, A,; Garcia-Granda, S.; PBrezCarrefio, E. J.Am. Chem. SOC.1994,116, 11191.

(14)(a) Reissig, H. Top. Curr. Chem. 1988, 114, 73. (b) Wong, H. N.; Hon, M.; Tse, C.; Yip, Y.; Tanko, J.; Hudlicky, T. Chem. Reu. 1989, 89, 165.

C

d e f

3b 3c 3b 3b 3h

45 75

Vinylaminocarbenes of Group 6 Metals

Organometallics, Vol. 14, No. 3, 1995 1431

Scheme 4

4

CO2CH3

3h+

Tol, 111°C

7

2N H2S04 /N

I

\

92 0

0, (35 O h )

From Table 2, it seems that the olefin electronwithdrawing group plays an important role in the cyclopropanation reaction; thus, the best results for molybdenum complexes were obtained with methyl acrylate and acrylonitrile (entries b and d), but yields fall when methyl vinyl ketone is used (entry e). The generality of this reaction toward the electrondeficient diene 7 was further explored (Scheme 4). In this case, the divinylcyclopropaneIV,resulting from the cyclopropanation of the less sterically hindered double bond of the diene, undergoes Cope rearrangement under the reaction conditions, affording V. As far as we know, this is the first example of a seven-membered-ring formation by the tandem intermolecular cyclopropanatiodCope rearrangement reaction involving an aminovinyl Fischer type carbene and an electron-deficient diene.15 The attempted purification of that azulene derivative resulted in partial hydrolysis of the enamine group, but treatment of V with aqueous acid allowed us to isolate 8 in 35%overall yield from 3h. The results of this process complement earlier reports on the preparation of seven-membered rings by the reaction of electron-rich dienes and Fischer type oxyvinylcarbenes.3 In conclusion, we have reported a simple and direct synthesis of Fischer type aminovinylcarbenes,which are unknown in the case of molybdenum, from 2-amino-1,3butadienes. The chromium and molybdenum complexes thus obtained react with electron-deficient alkenes to furnish insertion products resulting from a cyclopropanation process; moreover, the first example of a tandem intermolecular cyclopropanatiodCope rearrangement between a Fischer-type vinylcarbene and an electrondeficient diene has been shown.

Experimental Section General Considerations. Tetrahydrofuran (THF) and toluene were distilled from benzophenone ketyl under nitrogen. Chromatographic purifications of carbenes 3 were performed (15)During the evaluation process of this paper, one example of a tandem intramolecular cyclopropanatiodCope rearrangement has been observed for a vinylcarbene complex and an electron-deficient diene: Harvey, D. F.; Grenzer, M. E.; Gantzel, P. K. J.Am. Chem. SOC.1994, 116,6719.

under nitrogen on previously degassed silica gel 60,230-400 mesh (Merck or Scharlau). TLC was performed on glassbacked plates coated with silica gel 60 F254 (Merck or Scharlau). Components were located by treating the plates with an acidic solution of Mo(V1) and Ce(N) and heating. Chromatographic solvents were distilled and degassed for carbenes 3 by bubbling nitrogen for 15 min prior to their use. NMR measurements were recorded on Bruker AC-200 or AC-300 spectrometers. IR analyses were obtained on Mattson 3000 FTIR spectrometer. MS spectra were recorded on a HewlettPackard 5987-A spectrometer. Elemental analyses were obtained on a Perkin-Elmer 240-B analyzer. 2-Amino-l,3-butadienes (la-c)16 and carbene complexes (2a-c)17 were prepared according t o the literature procedures. General Procedure for the Reactions of Amino Dienes 1 with Carbenes 2. Method A (for Chromium and Molybdenum Metal Complexes). To a 0.2 M solution of diene 1 in the solvent indicated are added 1.2-1.5 equiv of carbene 5, and the solution is refluxed until TLC (silica gel, hexane-ethyl acetate 3:l for la,c and hexane-ether-dichloromethane 4:l:l for lb) shows the absence of 1 in the reaction mixture. Partial decomposition of 2 and cyclopropanation in the caae of molybdenum complexes afford the metal hexacarbonyl. When the solvent is toluene and the metal used is chromium, hexacarbonylchromium sublimes and can be recovered on a cold finger; in other cases the hexacarbonylmetal species can be recovered by crystallization from the reaction mixture at -20 "C. After that, the solvent is removed at reduced pressure and the crude reaction mixture chromatographed on silica gel with the solvent indicated. Typically, the red, first-eluted fraction contains the starting carbene 2 and a-methoxystyrene (4) and the yellow, second one contains the aminocarbene 3. Method B (for Tungsten Complexes). 2-Amino diene 1 and 1.7 equiv of metal carbene 2 are dissolved in 70 mL of THF and heated in a sealed tube to 100 "C during the time indicated; then, the reaction mixture is cooled t o -20 "C in order to crystallize tungsten hexacarbonyl, filtered, and worked up as in method A. Pentacarbonyl[ (E)-l-morpholino-4-methoxy-2-methyl2-buten-l-ylidenelchromium(O) (3a;Method A). A 2 mmol (0.394 g) amount of N-[(E)-4-methoxy-2-methyl-l-methylenebut2-enyllmorpholine (la) and 2.4 mmol(0.749 g) of pentacarbonyl(methoxyphenylmethy1ene)chromium (0) (2a) are refluxed in toluene over 6 h. Column chromatography: 4 was first eluted with hexane-ethyl acetate (3:l) and 3a with hexaneethyl acetate (1:l);Rf 0.08 (hexane-ethyl acetate (3:l)). Yield: 0.562 g (75%). Mp: 71-73 "C (yellow prisms, recrystallized from hexane-dichloromethane). 'H NMR (CDC13): 6 1.71 (s, 3H), 3.28 (s, 3H), 3.62-3.80 (m, 4H), 3.89-3.98 (m, 4H), 4.26 (t d, lH, J = 5.2, 13.3 Hz), 4.36 (t d, l H , J = 4.7, 13.3 Hz), 4.95 (t, lH, J = 6.8 Hz). 13C NMR (CDC13): 6 14.7 (CH3), 54.2 (CH2), 58.0 (CH3), 59.7 (CHz), 67.7 (CHz), 67.8 (CHz), 115.3 (CH), 147.9 (C), 217.1 (C), 222.9 (C), 273.4 (C). IR (CH2C12, cm-l): 2054 m, 1927 s. Anal. Calcd for C15H17N07Cr: C, 48.01; H, 4.57; N, 3.73. Found: C, 47.94; H, 4.53; N, 3.69. Pentacarbonyl[ (E)-l-morpholino-4-methoxy-2-methyl2-buten-l-ylidene]molybdenum(O) (3b;Method A). A 2 mmol (0.394 g) amount of N-[(E)-4-methoxy-2-methyl-l-methylenebut-2-enyllmorpholine(la) and 2.4 mmol (0.854 g) of pentacarbonyl(methoxyphenylmethylene)molybdenum(O) (2b) are refluxed in tetrahydrofuran over 4 h. Column chromatography: 4 was first eluted with hexane-ethyl acetate (3:l) and 3b with hexane-ethyl acetate (1:l); RfO.09 (hexane-ethyl acetate (3:l)). Yield: 0.478 g (57%). Yellow oil. 'H NMR (CDC13): 6 1.76 (s, 3H), 3.32 (s, 3H), 3.68 (s, 2H), 3.77-4.01 (m, 6H), 4.21-4.39 (m, 2H), 4.99 (t, lH, J = 6.3 Hz). 13CNMR (16)Barluenga, J.;Aznar, F.; ValdBs, C.; Cabal, M. P. J.Org. Chem. 1991,56,6166. (17) Tumer, S. U.; Herndon, J. W.; McMullen, L. A. J.Am. Chem. SOC.1992,114,8394.

1432 Organometallics, Vol. 14, No. 3, 1995

Barluenga et al.

chromium(0) (2a) are refluxed in THF over 3 h and cooled to (CDC13): 6 14.1 (CH3), 53.0 (CH2),57.8 (CH3), 61.2 (CH21, 67.5 room temperature. In order to improve the yield of 3g, CO is (CH2),67.6 (CH2), 115.3 (CH), 147.8 (C), 206.0 (C), 213.2 (C), bubbled over 15 min. Then, the reaction mixture is cooled to 265.9 (C). IR (CH2Cl2,cm-I): 2054 m, 1927 s. Anal. Calcd -20 "C overnight. Column chromatography: hexane-ethyl for C ~ ~ H ~ ~ N OC,~42.97; M O : H, 4.09; N, 3.34. Found: C, 42.89; acetate (3:l);Rf0.33. Yield: 0.493 g (69%). Mp: 117-119 "C H, 4.14; N, 3.30. Pentacarbonyl[(E)-l-morpholino-4-methoxy-2-methyl- (yellow needles, recrystallized from hexane-dichloromethane). lH NMR (CDC13): 6 1.85 (br, lH), 1.99 (br, 2H), 2.36 (br, lH), 2-buten-l-ylidene]tungsten(O) (3c;Method B). A 2 mmol (0.394g) amount of N-[(E)-4methoxy-2-methyl-l-methylenebut 2.50 (br, lH), 2.75 (br, lH), 3.64 (s, 2H), 3.67-3.80 (m, 2H), 3.91 (t, 2H, J = 4.7 Hz), 4.28-4.36 (br, 2H), 5.13 (s, 1H). I3C 2-enyllmorpholine (la)and 3.4 mmol(l.510 g) of pentacarboNMR (CDC13): 6 23.2 (CH2),33.0 (CH2), 35.7 (CH2),54.4(CHd, nyl(methoxyphenylmethylene)tungsten(O)(2c)were reacted for 59.7 (CH2),67.8 (CH2), 119.4 (CHI, 152.6 (0,217.3 (0,223.3 38 h. Column chromatography: 4 was first eluted with (C), 272.1 (C). IR (CH2C12, cm-'1: 2054 m, 1929 s. Anal. hexane-ethyl acetate (3:l)and 3c with hexane-ethyl acetate Calcd for C15H15NO&r: C, 50.43; H, 4.23; N, 3.92. Found: (1:l);Rf 0.08 (hexane-ethyl acetate (3:l)). Yield: 0.649 g C, 50.24; H, 4.18; N, 3.88. (64%). Yellow oil. lH NMR (CDC13): 6 1.72 (s, 3H), 3.28 (s, 3H), 3.61-3.80 (m, 4H), 3.88 (t, 2H, J = 4.8 Hz), 3.96-4.02 Tetracarbonyl[(~2-1-cyclopentenyl)morpholinometh(m, 2H), 4.16-4.35 (m, 2H), 4.98 (t,lH, J = 6.7 Hz). 13CNMR ylene]chromium(O)(3'g). The complex 3 g was isolated from (CDC13): 6 14.6 (CH3), 53.1 (CHz), 58.1 (CH3), 62.1 (CHd, 67.7 the reaction of IC and 2a in 34% yield, but this yield can be (CHz), 116.1 (CH), 148.5 (C), 198.1 (C), 202.8 (C), 256.0 (C). increased by the following procedure: 1.52 mmol(O.543 g) of IR (CH2C12, cm-l): 2054 m, 1923 s. Anal. Calcd for C15H173g is dissolved in THF and heated under reflux until TLC (Rf N07W C, 35.53; H, 3.38; N, 2.76. Found: C, 35.40; H, 3.41; 0.33, hexane-ethyl acetate (3:l))shows the total consumption N, 2.78. of 3g. The reaction mixture is then concentrated under Pentacarbonylr (E)-1-morpholino-4-(tert-butyldireduced presure Torr). The red solid formed is redismethylsiloxy)-2-methyl-2-butenylidenelchromium(0) (3d; solved in CH2C12(10 mL) and filtered through a pad of Celite, and the solution is diluted with 25 mL of hexane. CrystalMethod A). A 2 mmol (0.594 g) amount of N-[(E)-4-(tertbutyldimethylsiloxy)-2-methyl-1-methylenebut-2-enyllmorpho- lization of compound 3'g from the solution at -20 "C yielded line (lb) and 3 mmol(0.936 g) of pentacarbonyl(methoxyphe0.451 g (90%)(RfO.19,hexane-ethyl acetate (3:l)). Mp: 137nylmethylene)chromium(O) (2a) are refluxed in toluene over 139 "C (red prisms). 'H NMR (CDC13): 6 1.35-1.64 (m, lH), 5.5 h. Column chromatography: hexane-ether-dichloro1.71-1.88 (m, lH), 1.96 (d,d,J = 7.8, 14.0 Hz, lH), 2.20-2.35 methane (4:l:l); Rf 0.26. Yield: 0.617 g (65%). Red oil. 'H (m, 2H), 2.51-2.67 (m, lH), 3.63-4.01 (m, 8H), 4.67 (s, 1H). NMR (CDC13): 6 0.02 (s, 6H), 0.83 (s, 9H), 1.68 (s, 3H), 3.64 I3CNMR (CD~C12,233K): 6 21.0 (CHz), 31.1 (CH2),35.4 (CH2), (s, 2H), 3.68-3.86 (m, 2H), 3.93 (t, 2H, J = 5.1 Hz), 4.19 (d, 57.0 (CH?), 58.5 (CH2), 67.1 (CH21, 67.5 (CH2),85.0 (CH), 86.6 2H, J = 6.3 Hz), 4.25-4.44 (m, 2H), 4.90 (t, lH, J = 6.3 Hz). (C), 222.0 (C), 224.2 (C), 234.9 (C), 235.8 (C), 257.6 (C). IR I3C NMR (CDC13): 6 -5.5 (CH3), -5.4 (CH3), 14.6 (CH3), 18.1 (CH2C12, cm-I): 1879, 1908, 2011, 2045. Anal. Calcd for (C), 25.7 (CH3),54.1 (CH2),58.2 (CHz),59.7 (CH2),67.7 (CHz), C14H15N05Cr: C, 52.79; H, 4.43; N, 4.10. Found: C, 52.58; 118.4 (CH), 145.6 (C), 217.2 (C),223.0 (C), 274.0 (C). IR (CHzH, 4.44; N, 4.05. C12,cm-I): 2054 m, 1927 s. Anal. Calcd for C2oH29NO.iSiCr: Pentacarbonyl[morpholino(1-cyclopenteny1)methylC, 50.52; H, 6.15; N, 2.95. Found: C, 50.63; H, 6.18; N, 2.97. enelmolybdenum(0) (3h; Method A). A 2 mmol (0.358 g) Pentacarbonylr(E)-l-morpholino-4-(tert-butyldimeth- amount of N-(1-cyclopent-1-enylethenyl)morpholine (IC)and ylsiloxy)-2-methyl-2-butenylidenelmolybdenum(0) (3e; 2.4 mmol(0.854 g) of pentacarbonyl(methoxyphenylmethy1ene)Method A). A 2 mmol (0.594 g) amount of N-[(E)-4-(tertmolybdenum(0) (2b)are refluxed in THF over 2.5 h. Column butyldimethylsiloxy)-2-methyl-l-methylenebut-2-enyllmo~hochromatography: hexane-ethyl acetate (3:l); Rf 0.33. Yield: line (lb) and 3.0 mmol (1.068 g) of pentacarbonyUmethox0.441 g (55%). Mp: 122-125 "C (yellow needles, recrystallized yphenylmethylene)molybdenum(O)(2b)are refluxed in toluene from hexane-dichloromethane). 'H NMR (CDC13): 6 1.87over 1 h. Column chromatography: hexane-ether-dichlo1.97 (m, 2H), 2.44 (br, 4H), 3.66 (s, 4H), 3.88 (t, 2H, J = 4.8 romethane (5:l:l);Rf0.33. Yield: 0.363 g (35%). Red oil. 'H Hz), 4.21-4.32 (m, 2H), 5.10 (s, 1H). I3C NMR (CDC13): 6 23.4 NMR (CDC13): 6 0.00 (s, 6H), 0.82 (s, 9H), 1.67 (s, 3H), 3.63 (CH2), 33.2 (CHz), 35.4 (CH2), 53.4 (CH2), 61.3 (CH2), 67.8 (s, 2H), 3.85-3.99 (m, 4H), 4.12-4.41 (m, 4H), 4.90 (t, l H , J (CHz), 119.6 (CH), 152.4 (C), 206.2 (C), 213.6 (C), 265.3 (C). = 6.3 Hz). I3C NMR (CDC13): 6 -0.7 (CH3), -0.6 (CH3), 14.2 IR (CHzC12, cm-I): 2053 m, 1931 s. Anal. Calcd for C15H15(CH3), 18.2 (C), 25.7 (CH3), 53.0 (CH2),58.9 (CH2),61.3 (CHz), N06Mo: C, 44.90; H, 3.77; N, 3.49. Found: C, 44.94; H, 3.81; 67.8 (CH2), 118.5 (CH), 145.5 (C), 206.1 (C), 213.3 (C), 267.2 N, 3.51. (C). IR (CH2C12, cm-l): 2054 m, 1933 s. Anal. Calcd for Pentacarbonyl[morpholino(1-cyclopenteny1)methylC2oH2gNO.iSiMo: C, 46.24; H, 5.63; N, 2.70. Found: C, 46.37; eneltungsten(0) (3i;Method B). A 2 mmol(0.358 g) amount H, 5.69; N, 2.73. (IC)and 3.4 mmol Pentacarbonyl[(E)-l-morpholino-4-(tert-butyldimeth- of N-(1-cyclopent-1-enyletheny1)morpholine (1 510 g) of pentacarbonyl(methoxyphenylmethy1ene)tungstenylsiloxy)-2-methyl-2-butenylideneltungsten~O~ (3f;Method ( 0 ) (2c) were reacted for 12 h. Column chromatography: B). A 2 mmol(O.594 g) amount of N-[(E)-4-(tert-butyldimethhexane-ethyl acetate (3:l); Rf 0.31. Yield: 0.450 g (46%). ylsiloxy)-2-methyl-l-methylenebut-2-enyl]mo~holine(lb)and Mp: 154-156 "C (yellow needles, recrystallized from hexane3.4 mmol(l.510 g) of pentacarbonyl(methoxhenylmethy1ene)dichloromethane). 'H NMR (CDC13): 6 1.95 (br, 3H), 2.51 (br, tungsten(0) (2c) were reacted for 40 h. Column chromatog3H), 3.68 (s, 4H), 3.89 (t, 2H, J = 4.7 Hz), 4.27 (br, 2H), 5.17 raphy: hexane-ether-dichloromethane (5:l:l); Rf 0.35. (s, 1H). I3C NMR (CDC13): 6 23.4 (CH21, 33.0 (CH2), 35.5 Yield: 0.218 g (18%). Red oil. 'H NMR (CDC13): 6 0.00 (s, (CH2), 53.3 (CH2), 62.0 (CHz), 67.8 (CH2), 120.4 (CH), 153.2 6H), 0.82 (s, 9H), 1.67 (s, 3H), 3.61 (s, 2H), 3.81-3.88 (m, 4H), (C), 198.3 (C), 203.2 (C), 254.0 (C). IR (CH2C12, cm-'): 2052 4.12-4.32 (m, 4H), 4.93 (t, l H , J = 6.3 Hz). I3C NMR m, 1924 s. MS (m/e, relative intensity): (489, 6) M', (461, (CDC13): 6 -5.4 (CH3), -5.3 (CH3), 14.4 (CH3), 18.2 (C), 25.7 471, (431, 891, (401, 841, (372, 451, (345, 681, (317, 641, (290, (CH3),52.9(CH2),58.7(CH2),62.1(CH2),67.7(CH2),67.8(CH2) 100). Anal. Calcd for CI5H15NO6W C, 36.83; H, 3.09; N, 2.86. 119.2 (CHI, 146.1 (C), 198.2 (C), 202.9 (C), 256.4 (C). IR (CH2C, 36.93; H, 3.06; N, 2.86. Cl2, cm-I): 2052 m, 1923 s. Anal. Calcd for C ~ O H ~ ~ N O ~ S ~ Found: W: General Procedure for Ketones 6. A 1mmol amount of C, 39.44; H, 4.79; N, 2.29. C, 39.55; H, 4.81; N, 2.31. Found: carbene complex 3 and 1.1mmol of alkene 5 are dissolved in Pentacarbonyl[morpholino(1-cyclopenteny1)methyl3 mL of toluene and refluxed until TLC shows the total enelchromium(0) (3g; Method A). A 2 mmol (0.358 g) consumption of starting carbene 3 (see Table 2). The M(CO)6 amount of N-(1-cyclopent-1-enyletheny1)morpholine(IC)and formed is crystallized at -20 "C and the solution concentrated 2.4 mmol(0.749 g) of pentacarbonyl(methoqhenylmethy1ene)

Vinylaminocarbenes of Group 6 Metals

Organometallics, Vol. 14, No. 3, 1995 1433

Methyl 4-(l-cyclopentenyl)-4-oxobutanoate (60:0.401 g of 3h and 99 p L of methyl acrylate. Column chromatogra(E)-Methyl 7-methoxy-5-methyl-4-0~0-5-heptenoate phy: hexane-ethyl acetate (3:l);RfO.37. Yield 0.137 g (75%). 'H NMR (CDCl3): 6 1.85 (quintet, J = 7.7 Hz, 2H), 2.46-2.51 (6a): 0.375 g of 3a,0.419 g of 3b,or 0.507 g of 3c and 99 pL (m, 4H), 2.56 (t, J = 6.9 Hz, 2H), 2.94.(t, J = 6.9 Hz, 2H), 3.62 of methyl acrylate. Column chromatography: hexane-ethyl (s, 3H), 6.74 (9, 1H). 13C NMR (CDC13): 6 22.6 (CHz), 27.8 acetate (3:l);RfO.19. Yield: 0.132 g, 66% (3a);0.140 g, 70% (CH2), 30.5 (CHz), 33.4 (CH2), 33.8 (CH2), 51.7 (CH31, 143.8 (3b);0.060 g, 30% (3~).'H NMR (CDCl3): 6 1.69 ( 8 , 3H), 2.55 (CH), 145.0 (C), 173.5 (C), 196.4 (C). IR (neat, cm-l): 1668, (t,J = 6.7 Hz, 2H), 2.96 (t,J = 6.7 Hz, 2H), 3.33 (s, 3H), 3.61 1739. MS (mle,relative intensity): 182, 1 (M+); 150, 44; 95, (~,3H),4.11(d,J=5.7Hz,2H),6.64(t,J=5.7Hz,lH). 13C 100. Anal. Calcd for C10H1403: C, 65.92; H, 7.74. Found: C, NMR (CDC13): 6 11.5 (CH3),27.9 (CH2), 31.8 (CH2), 51.6 (CH3), 66.04; H, 7.72. 58.5 (CH3), 69.4 (CHz), 136.9 (C), 138.5 (CH), 173.2 (C), 198.8 6-(Methoxycarbonyl)-5-bicyclo[5.3.0ldecen-2-one (8). (C). IR (neat, cm-l): 1675, 1740. MS (mle, relative intenA solution of 0.401 g (1mmol) of 3h and 129 pL (1.1mmol) of sity): 200, 1 (M+); 168, 56; 114, 100; 109, 35; 87, 47; 85, 45. methyl 2,4-pentadienoate in toluene is refluxed for 7.5 h. The Anal. Calcd for C10H1604: C, 59.98; H, 8.05. Found: C, 59.91; reaction mixture is cooled to -20 "C for 10 h, filtered, and H, 8.04. concentrated. The residue is treated with a mixture of (E)-7-Methoxy-5-methy1-4-0~0-5-heptenenitrile (6d): (5 mL) and 2 N aqueous H2S04 (5 mL) for 1 tetrahydrofuran Column chromatog0.419 g of 3b and 72 pL of acrylonitrile. h, extracted with diethyl ether, dried with anhydrous NazS04, raphy: hexane-diethyl ether-dichloromethane (2:1:1); Rf and concentrated. The resulting oil is chromatographed (silica 0.19. Yield: 0.130 g (78%). 'H NMR (CDC13): 6 1.72 (s, 3H), gel, hexane-ethyl acetate (3:l)): Rf0.36. Yield: 0.073 g (35%). 2.57 (t, J = 7.3 Hz, 2H), 3.03 (t,J = 7.3 Hz, 2H), 3.34 (6, 3H), lH NMR (CDC13): 6 1.02-1.55 (m, 3H), 1.55-1.88 (m, 4H), NMR 4.12 (d, J = 5.6 Hz, 2H), 6.61 (t, J = 5.6 Hz, 1H). 1.96, 2.47 (m, 3H), 2.47-2.72 (m, lH), 3.25 (d t, J = 16.2, 11.4 (CDC13): 6 11.4 (CH31, 11.7 (CH2),32.6 (CH2),58.6 (CH3),69.3 Hz, lH), 3.68 (s, 3H), 7.24 (d d, J = 8.1, 5.2 Hz, 1H). 13CNMR (CH2), 119.1 (C), 136.4 (C), 139.8 (CH), 196.1 (C). IR (neat, (CDC13): 6 25.4 (CHz),26.5 (CH2),29.8 (CHz),30.6 (CH2),33.7 cm-l): 1672,2249. MS (mle,relative intensity): 167,5 (M+); (CH2), 42.9 (CH), 52.0 (CH3), 57.4 (CHI, 135.2 (C), 147.7 (CHI, 127,42; 95, 100; 85,67. Anal. Calcd for C~H13N02:C, 64.65; 165.1 (C), 202.4 (C). IR (neat, cm-l): 1725, 1696. MS (mle, H, 7.84; N, 8.38. Found: C, 64.71; H, 7.90; N, 8.35. relative intensity): 205,4 (M+);176, 84; 148, 80; 139,45; 126, (E)-8-Met hoxy-6-methyl-6-octene-2,5-dione (6e): 0.419 60; 121, 57; 120, 74; 108, 75; 98, 100; 91,53; 79,61; 68, 57; 67, g of 3b and 91 pL of methyl vinyl ketone. Column chromato42. Anal. Calcd for C12H1603: C, 69.21; H, 7.74. Found: C, graphy: hexane-diethyl ether-dichloromethane (2:l:l); Rf 69.12; H, 7.79. 0.24. Yield: 0.083 g (45%). lH NMR (CDC13): 6 1.69 (s, 3H), 2.15 (s, 3H), 2.67 (t,J = 7.3 Hz, 2H), 2.91 (t,J = 7.3 Hz, 2H), Acknowledgment. This research was supported by 3.33 (s, 3H), 4.11 (d, J = 5.1 Hz, 2H), 6.67 (t,J = 5.1 Hz, 1H). the Direcci6n General de Investigacih Cientifica y 13C NMR (CDC13): 6 11.6 (CH3), 30.0 (CH31, 30.1 (CH2), 37.0 TBcnica (DGICYT; Grant No. PB92-1005).An MEC (CHz),58.6 (CH3),69.5 (CH2), 137.0 (C), 138.5 (CH), 199.3 (C), Fellowship to A.M. is gratefully acknowledged. 207.4 (C). Anal. Calcd for C10H1603: C, 65.19; H, 8.75. OM9408021 Found: C, 65.11; H, 8.72. and chromatographed on silica gel in the solvent indicated below to give the products as colorless oils.