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Organometallics 1992,11,2024-2029
ond step is a CO insertion reaction into the metal-bon bond of the thiametallacycle to yield complex 8 containing an acyl function. Both of these steps can be reversed by mild heating or by the application of W-vis irradiation. We have observed a similar CO insertion into the complex OS~(CO)~~[G~-SCH~CM~~CH~)~]> However, in that example the keto function bridges the cluster in a p-q2 mode. Alper et al. have produced ythiobutyrolactones catalytically via regiospecific carbonylations of thietane, 2methylthietane, and 3-methoxythietaneusing cobalt and ruthenium carbonyls as catalyst precursors.16 We believe that compounds 6 and 8 provide viable models for intermediates that might be involved in the catalytic reactions observed by Alper. Efforta to obtain further support for this are in progress. In related studies we have shown that nucleophiles including C1- add directly to the bridging 3,3-DMT ligand (16)Wmg, M. D.; Cdet, S.; Alper, H. J. Org. Chem. 1989,54, 20.
in complex 2 to open the thietane ring through cleavage of a carbon-sulfur bond.436 Herein, we have demonstrated that the addition of Cl- to the thiametallacycliccomplex 6 proceeds by addition to the metal atoms and not to the opened thietane ligand. Thus, the thiametallacyle in 6 is not as susceptible to nucleophilic addition as is the intact, bridging 3,3-DMT ligand in 2. Acknowledgment is made to the donors of the Petroleum Research Fund, administered by the American Chemical Society, and the Office of Basic Energy Sciences of the US.Department of Energy for support of this research. Supplementary Material Available: Tables of hydrogen atom positional parameters and anisotropic thermal parametere (15 pages). Ordering informationis given on any current masthead page. Structure factor tables for the structural analyses of compounds 3, 4, and 9 were deposited previ~ualy.~~~
OM9211733
Reactions of Amides with Zerovalent and Divalent Palladium and Platinum Complexes David R. Schaad and Clark R. Landis' Departments of Ch6misby and Biochemistry. University of cdoredo-Bou&w, Boukk, Cobrado 80309, and Depertment of Chemkby, University of Wisconsin, M d b n , Wisconsin 53706
Received October 27, 799 7
The reactions of amidea (RCONH2 and CF3SO2NHJ with &Pd(CHJ2 and &Pt(CHJ2 and with transient LzPtoto yield new complexes containing palladium- and platinum-amido nitrogen bonds are reported. Photolysis of Pt(C204)(PEt,)2(1)in the presence of amide generates producta of the type trans-PtH(HNR)(PEt& (R = S02CF3 (la),COCF3 Ob)). Reaction of amides with trans-PtH(CH,)(PEt& (2), cis-PdMe2(PEtd2(31, cis-PtMedPEth (41, PdMe2(dcpe) (51, PdMe2(dmpe)(6), and PtMe2(COD)(7) produces la,b, trans-PdMe(HNR)(PEt& (R = S02CF3(3a), COCF3 (3b), COCF2H (34, COPh (3d)), PtMe(HNR)(PE9)2(R = S02CF3 ( 4 4 , COCFB(4b)),PdMe(HNR)(dcpe)(R = S02CF3(sa),COCF3(5b), COPh (541, PdMe(HNS02CF3)(dmpe)(6a), and PtMe(HNR)(COD) (R = SOzCF3(74, COCF:, (7b)), respectively. The stereochemistry and topologies of the new compounds are established by multinuclear NMR spectroscopy. The relevance of these reactions to hydroamination catalysis is discussed. Introduction The activation of N-H bonds' by transition-metalcomplexes2 is an integral feature of recent developments in hydroamination catal~sis.~.~ Our research on the design of new hydroamination catalysts has focused on the reactions of amides at metal centers because (1) amides are synthetic equivalents of the simplest hydroamination reagent, ammonia, and (2)the relatively high acidity of amide VB ammonia N-H bonds may provide a lower energy pathway for metal-facilitatedfunctionalization. We have previously reported that amides react with cis-FeH2and cis( d m ~ e ) FeH(C6H4PPhCH2CH2PPh2)(dppe), ~, RuH(naphth~l)(dmpe)~ (dmpe = 1,2-bis(dimethylphosphin0)ethane; dppe = 1,2-bis(diphenylphosphino)ethane) to generate tr~ns-M(H)(RNH)(diphosphine)~ complexes? Herein we report the extension of these studies to zerovalent and divalent palladium and platinum compounda containing phosphine and olefin ligands. Steps relevant to hydroamination catalysis include transition-metal-promoted N-H bond activation, insertion of an olefin into a M-C or M-N bond, and reductive *Towhom correspondence should be addreaaed at the Unfvemity of Wisconsin.
elimination or protonolysis to form the hydroamination product and regenerate the catalyst. We report the re(1)Herein we use the term N-H bond activation to indicate cleavage of an N-H bond induced by a metal center via homolytic cleavage, heterolytic cleavage, or oxidative addition. (2)(a)Roundhill,D. M Znorg. Chem. 1970,9,254.(b) Nelson, J. H.; Schmidt, J. L;Henry, R. A; Moore, D. W.; Jonaseen, H. B.Znorg. Chem. 1970,9,2678. (c) Sappa, E.;Milone, L. J. Organomet. Chem. 1973,61, 383. (d) Rauchfuss, T. B.;Roundhill,D. M. J. Am. Chem. SOC. 1974,96, 3098. (e) Bryan,E. G.; Johnson, B. F. G.; Lewis, J. J. Chem. Soc., Dalton Trans. 1977,1328. (0Forniee, J.; Green, M.; Spencer, J. L.; Stone, F. G. A. J. Chem. SOC.,Dalton Trans. 1977,1006. (g) Sum-Fink, G. Z . Naturforsh., B Anorg. Chem., Org. Chem.1980,36B,454. (h) Johnson, B. F. G.; Lewis,J.; Odiaka,T. I.; Fkithby, P.R. J. Organomet. Chem.1981, 216,C56. (i) Yamamoh, T.; Sano, K.;Yamamoto, A. Chem. Lett 1982, 207. (j) Hedden, D.;Roundhill,D. M.;Fultz, W. C.; Rheingold, A. L. J. Am. Chem. Soc. 1984,I @ , 6014. (k) Hillhouse, G. L.; Bercaw, J. E. J. Am. Chem. Soc. 1984,1@,6472. (1) Lin, Y.C.; Mayr, A.; Knobler, C. B.; Kaesz, H. D. J. Organomet. Chem. 1984,272,207. (m) Park,S.;Hedden, D.; Roundhill, D. M. Organometallics 1986,5,2161. (n) Bercaw, J. E.; Daviea, D. L.; W o h k i , P.T.Organometallics 1986,5,443. ( 0 ) Caealnuovo, A. L.; Calabreee, J. C.; Milntein, D. Znorg. Chem. 1987,26,971. (p) Waleh, P.J.; Hollander, F.J.; Bergman, R G. J. Am. Chem. Soc. 1988, 110,8729. (s)Park,5.;Johmon, M.P.;Roundhill,D. M. Organometallics 1989,8,1700.(r) Ladip, F. T.; Merole, J. S . Inorg. Chem. 1990,W ,4172. ( 8 ) Humthouse, M. B.;Mazid, M. A.; Robinson, S. D.; Sahajpal, A. J. Chem. Soc., Chem. Commun. 1991,1146. (3) Caealnuovo, A. L.; Calabrese, J. C.; Milatein, D. L. J. Am. Chem. Sac. 1988,110,6738.
0276-733319212311-2024$03.00/00 1992 American Chemical Society
Reactions of Amides with Pd and Pt Complexes
Figure 1. 'H NMR hydride signals (300MHz, acetonitrile-d3; with 'g6pt satellites): (A) trans-PtH(HNCOCF,)(PEt&; (B)
~~u~~~-P~H(H'~NCOCF~)(PE~&. actions of amides to form complexes of the general formula truns-MX(amido)Y, (M = Pt, Pd; X = H, CH3;Y = P E t , Yz = dcpe (1,2-bis(dicyclohexylphospho)ethane),dmpe, COD (1,5-cyclooctadiene)) by two routes. One, formal N-H oxidative addition to a Pt(0) intermediate, is analogous to the oxidative addition of the N-H bond of aniline to an Ir(1) center in the hydroamination cycle reported by CasaJnuovoet aL3 The other, protonolysis of a M 4 bond in divalent palladium and platinum compounds, has been proven to occur in the catalytic hydroamination pathway reported by Marks et aL4 Results Formation of trans-PtH(HNR)(PEt& (la,b). Method 1. Trogler et have reported that irradiation of Pt(C204)(PEt& (1) with UV light in the presence of substrates XY (X = Me, MeO, EbSi; Y = C1, H) yields complexes of the type PtXY(PEt&, formed by the loss of 2 equiv of COz followed by oxidative addition of XY to a Pt(0) intermediate (eq 1). The oxalate complex has been shown to react photochemically with hydrogen' and disilenesa as well, to form Pt(I1) complexes.
XY
Pt(C204)(PEb)z
[Pto(PEt3)21 Pt"(PEt3)2XY (1) Small-scale photolysis of 1 in the presence of the acidic amidesg triflamide and trifluoroacetamide produces trans-PtH(HNR)(PEtJ, (R = S02CF3(la),COCF3(lb)) complexes (eq 2), presumably via the highly reactive Pt(0) intermediate. The products are characterized readily by
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