Palladium-assisted formation of carbon-carbon bonds. 4. Synthesis and reactivity of a water-soluble (2,3,4-Trimethoxy-6-(ethoxymethyl)phenyl)palladium(II) complex. Reactions with alkynes of its derivatives: Further insight into the pathway of formation of highly functionalized organic spirocycles and X-ray structures of model intermediates

Article abstract of DOI:10.1021/om950603x

Mercuration of 3,4,5-trimethoxybenzyl chloride with mercury(II) acetate in ethanol, and further addition of aqueous NaCl, affords the compound [Hg(Ar)Cl] (1) [Ar = C₆H(CH₂OEt)-6-(OMe)₃-2,3,4], which reacts with (Me4N)Cl to give [Hg(Ar)₂] (2). Complex 2 reacts with K₂[PdCl₄] in water/acetone to give solutions from which, after addition of 2,2′-bipyridine (bpy), N,N,N′,N′-tetramethylethylenediamine (tmeda) or pyridine (py), complexes [Pd(Ar)-Cl(bpy)] (3), [Pd(Ar)Cl(tmeda)] (4), or trans-[Pd(Ar)Cl(py)₂] (5), respectively, can be isolated. Complex 3 reacts with PPh₃ and NaClO₄ to give [Pd(Ar)(bpy)(PPh₃)]ClO₄ (6). Treatment of 5 with AgClO₄ and py affords [Pd(Ar)(py)₃]ClO₄ (7), which reacts with PPh₃ to give CtS-[Pd-(Ar)(py)₂(PPh₃)]ClO₄ (8). A comparative study of the reactions of 3-5 with various alkynes has been carried out. Thus, 3 reacts with Tl(CF₃SO₃) and EtC=CEt or with AgClO₄ and PhC=CPh to give the (π-allyl)palladium complex (η ³-10-(ethoxymethyl)-6,7,8-trimethoxy-1,2,3,4-tetraethylspiro[4.5]-l, 3,6-decatrien-8-enyl)(bpy)palladium(II) trifluoromethano-sulfonate (9) or the monoinserted complex [Pd{cis-C(Ph)=C(Ph){C₆H(CH₂OEt)-O-(OMe) ₃-2,3,4}}(bpy)]ClO₄ (10), respectively. Complex 10 reacts with PPh₃ giving [Pd{cis-CPh=CPh-(Ar)}(PPh₃)(bpy)]ClO₄ (14). Complex 4 reacts with Tl(CF₃SO₃) and MeO₂CC=CCO₂Me or EtC=CEt yielding the vinyl-substituted complex [Pd{CiS-C(CO₂Me)=C(CO₂Me){C₆H(CH ₂OEt)-6-(OMe)₃-2,3,4}}(tmeda)]CF₃SO₃ (11) or the spirocyclic compound 10-(ethoxymethyl)-6,7-dimethoxy-1,2,3,4-tetraethylspiro[4.5]-l,3,6,9- decatetraen-8-one (12a). When 5 reacts with EtC=CEt, PhC=CPh, or ToC=CTo (To = C₆H₄Me-4), in the presence of Tl(CF₃SO₃) or AgClO₄, the corresponding spirocyclic compounds 12a, 12b (tetraphenyl), or 12c (tetratolyl), respectively, are obtained, whereas the reaction with MeO₂CC=CCO₂Me gives the diinserted complex trans-[Pd{cis,cis-C(CO₂Me)=C(CO₂Me)C(CO ₂Me)=C(CO₂Me)(Ar)}{OS(O)₂CF ₃}(py)₂] (13). The structures of compounds 6, 11, 12c, and 13 have been determined by X-ray diffraction.

Full text of DOI:10.1021/om950603x

24
Organometallics 1996, 15, 24-34
P a lla d iu m -Assisted F or m a tion of Ca r bon -Ca r bon Bon d s.
4.1 Syn th esis a n d Rea ctivity of a Wa ter -Solu ble
(2,3,4-Tr im eth oxy-6-(eth oxym eth yl)p h en yl)p a lla d iu m (II)
Com p lex. Rea ction s w ith Alk yn es of Its Der iva tives:
F u r th er In sigh t in to th e P a th w a y of F or m a tion of High ly
F u n ction a lized Or ga n ic Sp ir ocycles a n d X-r a y Str u ctu r es
of Mod el In ter m ed ia tes
J ose´ Vicente,*,† J ose´-Antonio Abad,*,‡ and Roc´ıo Ferna´ndez-de-Bobadilla
Grupo de Quı´mica Organometa´lica, Departamento de Quı´mica Inorga´nica,
Universidad de Murcia, Aptdo. 4021, Murcia, 30071 Spain
Peter G. J ones§ and M. Carmen Ram´ırez de Arellano
Institut fu¨r Anorganische und Analytische Chemie, Technische Universita¨t Braunschweig,
Postfach 3329, 38023 Braunschweig, Germany
Received August 2, 1995X
Mercuration of 3,4,5-trimethoxybenzyl chloride with mercury(II) acetate in ethanol, and
further addition of aqueous NaCl, affords the compound [Hg(Ar)Cl] (1) [Ar ) C6H(CH2OEt)-
6-(OMe)3-2,3,4], which reacts with (Me4N)Cl to give [Hg(Ar)2] (2). Complex 2 reacts with
K2[PdCl4] in water/acetone to give solutions from which, after addition of 2,2′-bipyridine
(bpy), N,N,N′,N′-tetramethylethylenediamine (tmeda) or pyridine (py), complexes [Pd(Ar)-
Cl(bpy)] (3), [Pd(Ar)Cl(tmeda)] (4), or trans-[Pd(Ar)Cl(py)2] (5), respectively, can be isolated.
Complex 3 reacts with PPh3 and NaClO4 to give [Pd(Ar)(bpy)(PPh3)]ClO4 (6). Treatment of
5 with AgClO4 and py affords [Pd(Ar)(py)3]ClO4 (7), which reacts with PPh3 to give cis-[Pd-
(Ar)(py)2(PPh3)]ClO4 (8). A comparative study of the reactions of 3-5 with various alkynes
has been carried out. Thus, 3 reacts with Tl(CF3SO3) and EtCtCEt or with AgClO4 and
PhCtCPh to give the (π-allyl)palladium complex (η3-10-(ethoxymethyl)-6,7,8-trimethoxy-
1,2,3,4-tetraethylspiro[4.5]-1,3,6-decatrien-8-enyl)(bpy)palladium(II)
trifluoromethano-
sulfonate (9) or the monoinserted complex [Pd{cis-C(Ph)dC(Ph){C6H(CH2OEt)-6-(OMe)3-
2,3,4}}(bpy)]ClO4 (10), respectively. Complex 10 reacts with PPh3 giving [Pd{cis-CPhdCPh-
(Ar)}(PPh3)(bpy)]ClO4 (14). Complex 4 reacts with Tl(CF3SO3) and MeO2CCtCCO2Me or
EtCtCEt yielding the vinyl-substituted complex [Pd{cis-C(CO2Me)dC(CO2Me){C6H(CH2OEt)-
6-(OMe)3-2,3,4}}(tmeda)]CF3SO3 (11) or the spirocyclic compound 10-(ethoxymethyl)-6,7-
dimethoxy-1,2,3,4-tetraethylspiro[4.5]-1,3,6,9-decatetraen-8-one (12a ). When 5 reacts with
EtCtCEt, PhCtCPh, or ToCtCTo (To ) C6H4Me-4), in the presence of Tl(CF3SO3) or
AgClO4, the corresponding spirocyclic compounds 12a , 12b (tetraphenyl), or 12c (tetratolyl),
respectively, are obtained, whereas the reaction with MeO2CCtCCO2Me gives the diinserted
complex trans-[Pd{cis,cis-C(CO2Me)dC(CO2Me)C(CO2Me)dC(CO2Me)(Ar)}{OS(O)2CF3}(py)2]
(13). The structures of compounds 6, 11, 12c, and 13 have been determined by X-ray
diffraction.
The synthesis of spirocyclic compounds is of interest
been reported to give spirocycles. We have reported
on the synthesis of (trimethoxyaryl)palladium com-
plexes6 and their uses in organic synthesis.7 Spe-
in the chemistry of natural2 and pharmaceutical prod-
ucts. Thus, formation of a spiro compound is a key step
in the synthesis of fredericamycin A, an important
compound for the chemotherapy of human cancers.3
However, these syntheses usually require specially
designed starting materials and complicated multistep
processes. Some catalytic4 and a few stoichiometric5
reactions using palladium compounds have recently
(4) Godleski, S. A.; Valpey, R. S. J . Org. Chem. 1982, 47, 381.
Stanton, S. A.; Felman, S. W.; Parkhurst C. S.; Godleski, S. A. J . Am.
Chem. Soc. 1983, 105, 1964. Godleski, S. A.; Heacock, D. J .; Meinhart,
J . D.; Wallendael, S. V. J . Org. Chem. 1983, 48, 2101. Anderson, P.
G.; Nilsson, Y. I. M.; Ba¨ckvall, J . E. Tetrahedron 1994, 50, 559. Brown,
R. D.; Godfrey, P. D.; McNaughton, D.; Pierlot, A. P. J . Am. Chem.
Soc. 1988, 110, 2329. Elsley, D. A.; McLeod, D.; Miller, J . A.; Quayle,
P. Tetrahedron Lett. 1992, 33, 409. Grigg, R.; Sridharan, V.; Stevenson,
P.; Sukirthalingam, S. Tetrahedron 1989, 45, 3557. Wu, G. Z.; Lamaty,
F.; Negishi, E. I. J . Org. Chem. 1989, 54, 2507. Ashimori, A.; Overman,
L. E. J . Org. Chem. 1992, 57, 4571. Katz, T. J .; Gilbert, A. M.;
Huttenloch, M. E.; Min-Min, G.; Britzinger, H. H. Tetrahedron Lett.
1993, 34, 3551. Trost, B. M.; Shi, Y. J . Am. Chem. Soc. 1991, 113,
701. Lee, G. C. M.; Tobias, B.; Holmes, J . M.; Harcourt, D. A.; Garst,
M. E. J . Am. Chem. Soc. 1990, 112, 9330. Tao, W.; Silverberg, L. J .;
Rheingold, A. L.; Heck, R. F. Organometallics 1989, 8, 2550. Abelman,
M. M.; Overman, L. E. J . Am. Chem. Soc. 1988, 110, 2328. Grigg, R.;
Fretwell, P.; Meerholtz, C. Sridharan, V. Tetrahedron 1994, 50, 359.
† E-mail: J VS@FCU.UM.ES.
‡ E-mail: J AAB@FCU.UM.ES.
§ E-mail: P.J ONES@TU-BS.DE.
X Abstract published in Advance ACS Abstracts, November 15, 1995.
(1) Part 3: Vicente, J .; Abad, J . A.; Gil-Rubio, J .; J ones, P. G.
Organometallics 1995, 14, 2677.
(2) Kong, K. C.; Cheng, C. H. Organometallics 1992, 11, 1972 and
references therein.
(3) Kelly, T. R.; Bell, S. H.; Ohashi, N.; Armstrong-Chong, R. J . J .
Am. Chem. Soc. 1988, 110, 6471.
0276-7333/96/2315-0024$12.00/0 © 1996 American Chemical Society

Pd-Assisted Formation of C-C Bonds
Organometallics, Vol. 15, No. 1, 1996 25
Sch em e 1
cifically, (6-acetyl-2,3,4-trimethoxyphenyl)palladium com-
plexes react with diarylalkynes to give highly function-
alized spirocyclic compounds (see Scheme 1).1 In this
paper we report the synthesis of new spirocyclic com-
pounds.
Reactions of arylpalladium complexes with alkynes
is a topic of current interest since they lead to new
organopalladium complexes derived from the insertion
of one, two or three alkynes into the Pd-C bond, or to
organic compounds of various types.8 Thus, for ex-
ample, we have shown that (2,3,4-trimethoxyphenyl)-
palladium complexes react with alkynes to give indenols
or indenones when a formyl substituent is in the
6-position.7a However, benzofulvenes or spirocyclic
compounds are obtained when the 6-acetyl derivative
reacts with dialkyl- or diarylacetylenes, respectively (see
Scheme 1).1,7b The marked influence of the nature of
the 6-substituent prompted us to study the reactivity
of (6-(ethoxymethyl)-2,3,4-trimethoxyphenyl)palladium
complexes with various alkynes. One of the main
differences between this study and those previously
reported is that our does not involve a cyclopalladated
complex as the starting material.
It is interesting to synthesize organic derivatives
containing the trimethoxyphenyl group as it is fre-
quently encountered in organic molecules of pharma-
ceutical interest, e.g. the antileukemic lactones stega-
nacin and steganangin,9 the antibacterial agent tri-
methoprim,10 or the cytotoxic colchicine.11
In this paper, we report the first study on the
reactivity of arylpalladium complexes with alkynes in
relation to the nature of the neutral ligands attached
to palladium. We have succeeded in isolating and
characterizing a complete set of models for the inter-
mediates in the synthesis of spirocyclic compounds.
Ch a r t 1
(5) Pfeffer, M.; Sutter, J .-P.; Rotteveel, M. A.; De Cian, A.; Fischer,
J . Tetrahedron, 1992, 48, 2427. Dupont, J .; Pfeffer, M.; Theurel, L.;
Rotteveel, M. A. New J . Chem. 1991, 15, 551.
(6) (a) Vicente, J .; Abad, J . A.; Stiakaki, M. A.; J ones, P. G. J . Chem.
Soc., Chem. Commun. 1991, 137. (b) Vicente, J .; Abad, J . A.; J ones, P.
G. Organometallics 1992, 11, 3512. (c) Vicente, J .; Abad, J . A.; Gil-
Rubio, J .; J ones, P. G.; Bembenek, E. Organometallics 1993, 12, 4151.
(7) (a) Vicente, J .; Abad, J . A.; Gil-Rubio, J . J . Organomet. Chem.
1992, 436, C9. (b) Vicente, J .; Abad, J . A.; Gil-Rubio, J .; J ones, P. G.
Inorg. Chim. Acta 1994, 222, 1.
(8) (a) Heck, R. F. Palladium Reagents in Organic Syntheses;
Academic Press: NY, 1987. (b) Ryabov, A. D. Synthesis 1985, 233. (c)
Pfeffer, M. Recl. Trav. Chim. Pays-Bas 1990, 109, 567. (d) Dupont, J .;
Pfeffer, M.; Theurel, L.; Rotteveel, M. A. New J . Chem. 1991, 15, 551.
(e) Maassarani, F.; Pfeffer, M.; Le Borgne, G. Organometallics 1990,
9, 3003. (f) Sutter, J .-P.; Pfeffer, M.; De Cian, A.; Fischer, J .;
Organometallics 1992, 11, 386. (g) Pfeffer, M.; Rotteveel, M. A.; Le
Borgne, G.; Fischer, J . J . Org. Chem. 1992, 57, 2147. (h) Pfeffer, M.;
Sutter, J .-P.; De Cian, A.; Fischer, J . Organometallics 1993, 12, 1167.
(i) Pfeffer, M.; Sutter, J .-P.; Rotteveel, M. A.; De Cian, A.; Fischer, J .
Tetrahedron 1992, 48, 2427. (j) Ryabov, A. D.; Eldick, R. van; Le
Borgne, G.; Pfeffer, M. Organometallics 1993, 12, 1386. (k) Beydoun,
N.; Pfeffer, M.; De Cian, A.; Fischer, J . Organometallics 1991, 10, 3693.
(l) Maassarani, F.; Pfeffer, M.; Spencer, J .; Wehman, E. J . Organomet.
Chem. 1994, 466, 265. (m) Lo´pez, C.; Solans X.; Tramuns, D. J .
Organomet. Chem. 1994, 471, 265. (n) Maassarani, F.; Pfeffer, M.;
Spencer, J .; Wehman, E. J . Organomet. Chem. 1994, 466, 265. (o)
Spencer, J .; Pfeffer, M.; De Cian, A.; Fischer, J . J . Org. Chem. 1995,
60, 1005. (p) Albert, J .; Granell, J .; Sales, J .; Solans, X. J . Organomet.
Chem. 1989, 379, 177. (q) Maassarani, F.; Pfeffer, M.; Le Borgne, G.
Organometallics 1987, 6, 2043.
Exp er im en ta l Section
Infrared spectra were recorded on a FT-IR Perkin-Elmer
U-2000 spectrophotometer, in the range 4000-200 cm-1 using
Nujol mulls between polyethylene sheets. 1H and 13C NMR
spectra were recorded on a Brucker AC-200 or a Varian XL-
300 spectrometer and referenced to internal SiMe4. 31P NMR
spectra were measured on the Varian XL-300 machine with
external H3PO4 reference. Some signals in the NMR spectra
were assigned with the help of DEPT techniques. Conductivi-
ties were measured with
a Phillips 9501 conductimeter.
Melting points were determined on a Reichert apparatus and
are uncorrected. C, H, N, and S analyses were carried out
with a Carlo Erba EA 1108 microanalyzer with chromato-
graphic separations. Solvents were distilled prior to use. The
reactions were carried out at room temperature and without
precautions to exclude atmospheric moisture unless otherwise
stated. Chromatographic separations were performed using
preparative-scale TLC plates prepared by us from commercial
60-mesh silica gel. Chart 1 shows the organic groups attached
to the palladium atom and the numbering of the organic
spirocyclic compounds prepared.
(9) Ziegler, F. E.; Chliwner, I.; Fowler, K. W.; Kanfer, S. J .; Kuo, S.
J .; Sinha, N. D. J . Am. Chem. Soc. 1980, 102, 790. Tomioka, K.;
Ishiguro, T.; Mizuguchi, H.; Komeshima, N.; Koga, K.; Tsukagoshi, S.;
Tsuruo, T.; Tashiro, T.; Tanida, S.; Kishi, T. J . Med. Chem. 1991, 34,
54 and references therein.
(10) Chan, J . H.; Roth, B. J . Med. Chem. 1991, 34, 550 and
references therein.
Syn th esis of [Hg(Ar )Cl] (1). 3,4,5-trimethoxybenzyl chlo-
ride (5.0 g, 23.1 mmol) and Hg(AcO)2 (7.4 g, 23.1 mmol) were
(11) Ringel, I.; J affe, D.; Alerhand, S.; Boye, O.; Muzafar, A.; Brossi,
A. J . Med. Chem. 1991, 34, 3334.

26 Organometallics, Vol. 15, No. 1, 1996
Vicente et al.
mixed in ethanol (100 cm3), and AcOH (ca. 0.5 cm3) was added.
The resulting solution was refluxed for 5 h and poured into
aqueous NaCl (15 g in 300 cm3); after 1 h of stirring, the white
solid was filtered off, washed with water and hexane, and
dried in air. Yield: 7.9 g, 74%. Mp: 144 °C. IR: ν(HgCl)
(m, p-H, pyridine, 2H), 7.19 (m, m-H, pyridine, 4H), 6.57 (s,
HC6, 1H), 4.99 (s, CH2-aryl, 2H), 3.77 (s, MeO, 3H), 3.76 (s,
3
MeO, 3H), 3.73 (s, MeO, 3H), 3.61 (q, J ) 7 Hz,CH2Me, 2H),
1.24 (t, MeCH2, 3H). 13C{1H} NMR (75 MHz, CDCl3, ppm):
153.9, 153.7 (CH-py), 153.5, 137.5 (CH-py), 136.7, 124.9, 124.6
(CH-py), 124.0, 107.0 (CH-aryl) 75.1 (CH2), 66.3 (CH2), 60.7
(MeO), 60.2 (MeO), 55.9 (MeO), 15.5 (MeCH2). Anal. Calc for
334 (s) cm-1 1H NMR (300 MHz, CDCl3, δ): 6.59 (s, HC6, 1H),
.
4.44 (s, CH2-aryl, 2H), 3.91 (s, MeO, 3H), 3.86 (s, MeO, 3H),
3
3.84 (s, MeO, 3H), 3.52 (q, J HH ) 7 Hz, CH2Me, 2H), 1.37 (t,
C22H27N2ClPdO4: C, 50.30; H, 5.18; N, 5.33. Found: C, 49.96;
H, 5.28; N, 5.33.
MeCH2, 3H). 13C{1H} NMR (50 MHz, CDCl3): 155.9, 154.4,
140.8, 138.7, 132.5, 107.1 (CH-aryl) 72.7 (CH2), 66.9 (CH2), 61.1
(MeO), 60.7 (MeO), 56.1 (MeO), 15.2 (MeCH2). Anal. Calc for
Syn th esis of [P d (Ar )(bp y)(P P h 3)]ClO4 (6). Complex 3
(100 mg, 0.19 mmol), NaClO4 (27 mg, 0.19 mmol), and PPh3
(41 mg, 0.19 mmol) were mixed in CH2Cl2 (6 cm3) and stirred
for 1 h. The NaCl was filtered off and the resultant solution
partially evaporated. Addition of diethyl ether resulted in the
precipitation of yellow 6. Yield: 148 mg, 92%. Mp: 219 °C.
C
12H17ClHgO4: C, 31.24; H, 3.71. Found: C, 31.40; H, 3.59.
Syn th esis of [Hg(Ar )2] (2). 1 (7.0 g, 15.2 mmol) and
(NMe4)Cl (2 g) were mixed in acetone (350 cm3), refluxed for
4 h, and stirred overnight at room temperature. The solvent
was evaporated and the residue treated with CH2Cl2 (300 cm3)
and anhydrous MgSO4; the suspension was filtered over
anhydrous MgSO4 and the filtrate concentrated to ca. 20 cm3.
Addition of hexane precipitated 2 as a white solid. Yield: 3.4
g, 68%. Mp: 160 °C. 1H NMR (200 MHz, CDCl3, ppm): 6.81
(s, HC6, 1H), 4.50 (s, CH2-aryl, 2H), 3.94 (s, MeO, 3H), 3.88 (s,
Λ
M (acetone): 121 Ω-1 cm2 mol-1 1H NMR (200 MHz, CDCl3,
.
ppm): 8.72 (d, 3J HH ) 8 Hz, bpy, 2H), 8.35-8.11 (m, bpy, 2H),
7.81-7.19 (m, PPh3, 15H), 7.05 (m, bpy, 1H), 6.60 (s, HC6, 1H),
2
4.57, 4.51 (AB system, J AB ) 11 Hz, CH2-aryl, 2H), 3.79 (s,
MeO, 3H), 3.70 (s, MeO, 3H), 3.39 (s, MeO, 3H), 3.28 (“q”, 3J HH
) 7 Hz, CH2Me, 2H), 0.85 (“t”, MeCH2, 3H). 13C{1H} NMR
(75 MHz, CDCl3, ppm): 155.8, 155.4, 152.4, 150.4, 150.3, 149.7
(CH), 141.5 (CH), 141.4 (CH), 136.4, 136.3, 135.25, 135.23,
134.7 (CH), 134.5 (CH), 131.6 (CH), 129.7, 129.0, 128.8 (CH),
128.7 (CH), 126.70 (CH), 126.68 (CH), 126.5 (CH), 124.9 (CH),
124.54 (CH), 124.51 (CH), 108.9 (CH-aryl), 75.5 (CH2), 66.2
(CH2), 60.4 (MeO), 60.1 (MeO), 56.3 (MeO), 14.9 (MeCH2). 31P-
{1H} NMR (121.5 MHz, CDCl3, ppm): 24.0. Anal. Calc for
C40H40N2ClPPdO8: C, 56.54; H, 4.72; N, 3.29. Found: C, 56.44;
H, 4.87; N, 3.29. Single crystals of 6 were obtained by liquid
diffusion of diethyl ether into a solution of 6 in dichlo-
romethane.
3
2 × MeO, 6H), 3.59 (q, J HH ) 7 Hz, CH2Me, 2H), 1.21 (t,
MeCH2, 3H). 13C{1H} NMR (75 MHz, CDCl3, ppm): 158.0,
153.1, 152.8, 141.3, 140.7, 108.5 (CH-aryl) 74.9 (CH2), 65.6
(CH2), 60.9 (MeO), 60.4 (MeO), 55.9 (MeO), 15.1 (MeCH2).
Anal. Calc for C24H34HgO8: C, 44.27; H, 5.26. Found: C,
44.07; H, 5.26.
Syn th esis of [P d (Ar )Cl(bp y)] (3). A solution of 2 (358
mg, 0.55 mmol) in acetone (30 cm3) was added to a solution of
PdCl2 (98 mg, 0.55 mmol) and NaCl (100 mg, 1.7 mmol) in
water (12 cm3), and the resulting mixture was stirred until
all the solids dissolved (30 min). Evaporation of acetone
precipitated 1, and to the resulting aqueous solution bpy (87
mg, 0.55 mmol) and CH2Cl2 (16 cm3) were added. After 30
min the organic layer was decanted and the aqueous solution
extracted with CH2Cl2 (3 × 5 cm3). The combined extracts
were dried with anhydrous MgSO4 and filtered. Partial
evaporation of the solution (ca. 3 cm3) and addition of diethyl
ether gave 3 as a yellow solid. Yield: 264 mg, 92%. Mp: 208
°C. 1H NMR (200 MHz, CDCl3, ppm): 9.35-9.2, 8.1-7.8, 7.7-
7.5, 7.3-7.2, and 6.75-6.60 (5 m, bpy, 8H), 6.77 (s, HC6, 1H),
Syn th esis of [P d (Ar )(p y)3]ClO4 (7). Complex 5 (100 mg,
0.19 mmol) was reacted with AgClO4 (39 mg, 0.19 mmol) in
acetone (6 cm3) for 1 h. The suspension was filtered and
pyridine (ca. 0.15 cm3) added to the filtrate; the solution was
partially evaporated and diethyl ether added to give white 7.
Yield: 81 mg, 64%. Mp: 150 °C dec. ΛM (acetone): 130 Ω-1
3
cm2 mol-1
.
1H NMR (200 MHz, CDCl3, ppm): 8.65 (d, J HH
)
3
5 Hz, pyridine o-H, 4H), 8.54 (d, J HH ) 4.7 Hz, pyridine o-H,
2H), 7.6-8.0 (m, p-H, pyridine, 3H), 7.47 (m, m-H, pyridine,
2H), 7.32 (m, m-H, pyridine, 4H), 6.51 (s, HC6, 1H), 4.96 (s,
2
5.25, 4.85 (AB system, J AB ) 11.7 Hz, CH2-aryl, 2H), 4.10 (s,
MeO, 3H), 3.91 (s, MeO, 3H), 3.87 (s, MeO, 3H), 3.52 (“q”, 3J HH
) 7 Hz, CH2Me, 2H), 1.01 (“t”, MeCH2, 3H). 13C{1H} NMR
(75 MHz, CDCl3, ppm): 156.1, 154.1, 153.6, 152.1 (CH-bpy),
150.9, 149.2 (CH-bpy), 140.9, 139.2 (CH-bpy), 138.6 (CH-bpy),
137.5, 130.6, 126.5 (CH-bpy), 126.4 (CH-bpy), 122.2 (CH-bpy),
121.5 (CH-bpy), 107.2 (CH-aryl) 75.3 (CH2), 65.7 (CH2), 61.0
(MeO), 60.9 (MeO), 56.1 (MeO), 15.2 (MeCH2). Anal. Calc for
CH2-aryl, 2H), 3.86 (s, MeO, 3H), 3.82 (q, J ) 7 Hz, CH2Me,
3
2H), 3.76 (s, 2 × MeO, 6H), 1.32 (t, MeCH2, 3H). 13C{1H} NMR
(50 MHz, CDCl3, ppm): 153.7, 152.4 (CH-py), 151.4, 149.7 (CH-
py), 140.1, 139.0, 138.8 (CH-py), 136.7 (CH-py), 127.3, 126,3
(CH-py), 125.8 (CH-py), 107.7 (CH-aryl), 75.3 (CH2), 66.4
(CH2), 60.42 (MeO), 60.39 (MeO), 55.6 (MeO), 15.5 (MeCH2).
Anal. Calc for C27H32N3ClPdO8: C, 48.52; H, 4.83; N, 6.29.
Found: C, 48.43; H, 4.86; N, 6.29.
C
22H25N2ClPdO4: C, 50.49; H, 4.81; N, 5.39. Found: C, 50.25;
H, 4.84; N, 5.69.
Syn th esis of cis-[P d (Ar )(p y)2(P P h 3)]ClO4 (8). Complex
7 (100 mg, 0.15 mmol) was reacted with PPh3 (39 mg, 0.15
mmol) in refluxing acetone (6 cm3) for 8 h. The solution was
concentrated, and white 8 precipitated after diethyl ether
addition. Yield: 65 mg, 50%. Mp: 104 °C. ΛM (acetone): 126
Syn th esis of [P d (Ar )Cl(tm ed a )] (4). The yellow solid 4
was prepared analogously to 3, from PdCl2 (310 mg, 1.75
mmol), KCl (410 mg, 5.5 mmol), 2 (1140 mg, 1.75 mmol), and
tmeda (203 mg, 1.75 mmol). Yield: 609 mg, 72%. Mp: 145
°C. 1H NMR (200 MHz, CDCl3, ppm): 6.64 (s, HC6, 1H), 5.41,
Ω-1 cm2 mol-1
.
1H NMR (300 MHz, CDCl3, ppm): 8.6 (m,
2
4.82 (AB system, J AB ) 11 Hz, aryl-CH2, 2H), 3.86 (s, MeO,
3H), 3.85 (s, MeO, 3H), 3.80 (s, MeO, 3H), 3.73 (“q”, J HH
pyridine o-H, 2H), 8.38 (m, pyridine o-H, 2H), 7.8-7.0 (m, PPh3
+ py, 21H), 6.45 (s, HC6, 1H), 4.80, 4.58 (broad AB system,
CH2-aryl, 2H), 3.77 (s, MeO, 3H), 3.74 (s, MeO, 3H), 3.95-
3
)
7 Hz, CH2Me, 2H), 2.8-2.5 (m, CH2-tmeda, 4H), 2.69 (s,
MeN, 3H), 2.67 (s, MeN, 3H), 2.59 (s, MeN, 3H), 2.40 (s, MeN,
3H), 1.31 (“t”, MeCH2, 3H). 13C{1H} NMR (50 MHz, CDCl3,
ppm): 154.6, 150.6, 140.7, 137.4, 127.6, 107.6 (CH-aryl), 76.2
(CH2), 66.2 (CH2), 63.1 (CH2), 61.2 (MeO), 61.0 (MeO), 58.5
(CH2), 56.0 (MeO), 51.8 (Me-tmeda), 51.0 (Me-tmeda), 48.3
(Me-tmeda), 47.8 (Me-tmeda), 15.6 (MeCH2). Anal. Calc for
3
3.49 (m, CH2Me, 2H), 3.40 (s, MeO, 3H), 1.18 (“t”, J HH ) 7
Hz, MeCH2, 3H). 13C{1H} NMR (50 MHz, CDCl3, ppm): 152.2,
151.0, 150.4, 140.4, 138.2, 136.8, 136.7, 134.1, 133.9, 131.03,
130.98, 129.6, 128.7, 128.6, 128.5, 125.8, 107.7 (CH-aryl), 76.0
(CH2), 66.4 (CH2), 60.3 (MeO), 60.1 (MeO), 55.1 (MeO), 15.5
(MeCH2). 31P{1H} NMR (121.5 MHz, CDCl3, ppm): 28.4.
Anal. Calc for C40H42N2ClPPdO8: C, 56.41; H, 4.97; N, 3.28.
Found: C, 55.96; H, 5.05; N, 3.43.
C
18H33N2ClPdO4: C, 44.73; H, 6.88; N, 5.79. Found: C, 44.64;
H, 6.98; N, 5.81.
Syn th esis of tr a n s-[P d (Ar )Cl(p y)2] (5). The white 5 was
prepared analogously to 3 and 4 from PdCl2 (98 mg, 0.55
mmol), KCl (100 mg, 5.5 mmol), 2 (358 mg, 0.55 mmol), and
pyridine (ca. 0.5 cm3). Yield: 277 mg, 97%. Mp: 119 °C. 1H
NMR (300 MHz, CDCl3, ppm): 8.80 (m, o-H, pyridine 4H), 7.67
Rea ction of 3 w ith EtCtCEt. Syn th esis of 9. Complex
3 (100 mg, 0.19 mmol), Tl(CF3SO3) (67 mg, 0.19 mmol), and
EtCtCEt (31 mg, 0.38 mmol) were mixed in CH2Cl2 (10 cm3)
and stirred for 1 h. The mixture was filtered and the filtrate
evaporated to ca. 2 cm3. Addition of diethyl ether rendered

Pd-Assisted Formation of C-C Bonds
Organometallics, Vol. 15, No. 1, 1996 27
3
yellow 9. Yield: 88 mg, 58%. Mp: 114 °C. ΛM (acetone): 110
(t, J HH ) 7.5 Hz, 2 × MeCH2, 6H). 13C{1H} NMR (50 MHz,
CDCl3, ppm): 185.0 (CdO), 161.1, 153.3, 147.7, 140.6, 139.4,
126.5 (CH-aryl), 68.5 (C spiro), 66.7 (CH2O), 66.3 (CH2O), 60.5
(MeO), 60.1 (MeO), 19.13 (CH2Me), 19.08 (CH2Me), 15.0
(MeCH2O), 14.4 (MeCH2), 13.8 (MeCH2). Mass spectrum: m/ z
(% abundance) 375 (M+ + 1, 13), 374 (M+, 50), 299 (100), 288
(34), 141 (31), 129 (33), 128 (37), 115 (37), 91 (38), 57 (34), 55
(52). Tenacious solvents precluded satisfactory elemental
analyses.
Ω-1 cm2 mol-1 1H NMR (200 MHz, CDCl3, ppm): 8.6-8.8 (m,
.
bpy, 2H), 8.5-8.6 (m, bpy, 1H), 8.2-8.4 (m, bpy, 3H), 7.8-
7.65 (m, bpy, 1H), 7.65-7.5 (m, bpy, 1H), 5.65 (s, HC6, 1H),
3.85 (s, MeO, 3H), 3.72 (s, MeO, 3H), 3.6-3.3 (m, MeCH2 O,
2
2H), 3.57 (s, MeO, 3H), 3.31, 3.00 (AB system, J AB ) 13 Hz,
CH2-aryl, 2H), 2.95-2.2 (m, 3 × CH2Me, 6H), 2.2-1.8 (m, CH2-
3
Me, 2H), 1.20-1.04 (m, 3 × MeCH2, 9H), 1.03 (“t”, J HH ) 7
3
Hz, MeCH2O, 3H), 0.92 (“t”, J HH ) 7.5 Hz, MeCH2, 3H). 13C-
{1H} NMR (50 MHz, CDCl3, ppm): 154.5, 154.3, 150.8 (CH),
147.8, 147.6 (CH), 146.45, 141.3 (CH), 141.0 (CH), 139.4, 139.3,
127.35 (CH), 126.6 (CH), 124.6 (CH), 124.2 (CH), 119.3, 117.85,
70.1 (C spiro), 66.9 (MeCH2O + CH2-aryl), 62.2 (MeO), 60.1
(MeO), 56.1 (MeO), 20.9 (CH2), 19.3 (CH2), 19.1 (CH2), 18.5
(CH2), 15.0 (Me), 14.84 (Me), 14.76 (Me), 14.3 (Me), 14.05 (Me).
Anal. Calc for C35H45N2F3O7PdS: C, 52.46; H, 5.66; N, 3.49;
S, 4.00. Found: C, 52.44; H, 5.66; N, 3.64; S, 3.70.
Rea ction of 5 w ith Alk yn es. Syn th esis of 12a -c.
Complex 5 (100 mg, 0.19 mmol), EtCtCEt (50 mg, 0.61 mmol),
and Tl(CF3SO3) (67 mg, 0.19 mmol) were reacted in CH2Cl2 (6
cm3) for 24 h. The suspension was filtered over anhydrous
MgSO4 and the filtrate chromatographed; elution with diethyl
ether/hexane (1:1) gave yellow 12a . Yield: 39 mg, 55%.
12b was similarly prepared from 5 (100 mg, 0.19 mmol),
PhCtCPh (68 mg, 0.38 mmol), and AgClO4 (39 mg, 0.19 mmol)
as a yellow solid. Yield: 49 mg, 45%. Mp: 195 °C. IR
Rea ction of 3 w ith P h CtCP h . Syn th esis of 10. Com-
plex 3 (49 mg, 0.1 mmol) was reacted with AgClO4 (20 mg, 0.1
mmol) and PhCtCPh (17 mg, 0.1 mmol) in CH2Cl2 (6 cm3) for
4 h. The AgCl was filtered off over Celite, the filtrate
evaporated to ca. 2 cm3, and diethyl ether added to give a
precipitate of yellow 10. Yield: 64 mg, 88%. Mp: 159 °C, dec.
(Nujol): ν(CO) 1658 cm-1
.
1H NMR (200 MHz, CDCl3, ppm):
4
7.3-6.7 (m, 4 × Ph, 20H), 6.61 (t, J HH ) 1.5 Hz, HC6, 1H),
4.09 (d, CH2-aryl, 2H), 3.87 (s, MeO, 3H), 3.45 (s, MeO, 3H),
3
3.35 (q, J HH ) 7 Hz, MeCH2 O, 2H), 1.15 (t, MeCH2O, 3H).
13C{1H} NMR (50 MHz, CDCl3, ppm): 184.4 (CdO), 160.0,
151.2, 148.2, 142.9, 140.6, 134.9, 134.0, 129.9 (CH), 129.0 (CH),
128.1 (CH), 128.0 (CH), 127.6 (CH), 127.5 (CH), 127.3 (CH),
69.8 (C spiro), 67.3 (CH2), 66.9 (CH2), 60.9 (MeO), 60.4 (MeO),
15.2 (MeCH2). Anal. Calc for C39H34O4: C, 82.67; H, 6.05.
Found: C, 82.65; H, 6.13. Mass spectrum: m/ z (% abundance)
567 (M+ + 1, 45), 566 (M+, 100), 178 (16), 167 (30), 135 (28),
105 (PhCO+, 42), 91 (18), 77 (Ph+, 26), 59 (16).
ΛM (CH2Cl2): 36 Ω-1 cm2 mol-1 1H NMR (200 MHz, CDCl3,
.
ppm): 8.9-8.5 (m, bpy, 1H), 8.3-7.4 (m, bpy, 3H), 7.4-6.9
2
(m, bpy, Ph, HC6, 15H), 5.03, 4.62 (AB system, J AB ) 8.5 Hz,
CH2-aryl, 2H), 3.90 (s, MeO, 3H), 3.65 (s, MeO, 3H), 3.48 (“q”,
3J HH ) 7 Hz, CH2 Me), 3.14 (s, MeO, 3H), 1.21 (“t”, MeCH2,
3H). 13C{1H} NMR (50 MHz, CDCl3, ppm): 158.1, 153.1, 152.6
(CH), 152.04, 151.97, 151.5, 149.3 (CH), 144.15, 140.9 (CH),
140.4, 140.3 (CH), 134.7, 131.3, 130.4, 129.1 (CH), 128.7 (CH),
128.6 (CH), 128.1 (CH), 127.6 (CH), 127.1 (CH), 126.6 (CH),
123.8 (CH), 122.7 (CH), 110.5 (CH-aryl), 77.7 (CH2), 72.7 (CH2-
Me), 60.5 (MeO), 60.1 (MeO), 56.4 (MeO), 15.3 (MeCH2). Anal.
A similar procedure was used for preparing 12c from 5 (100
mg, 0.19 mmol), ToCtCTo (79 mg, 0.38 mmol), and Tl(CF3-
SO3) (67 mg, 0.19 mmol). Elution with hexane/acetone (4:1)
gave light-yellow 12c. Yield: 76 mg, 64%. Mp: 124 °C. IR
Calc for C36H35N2ClO8Pd: C, 56.48; H, 4.60; N, 3.67. Found:
C, 56.45; H, 4.80; N, 3.73.
(Nujol): ν(CO) 1658 cm-1
.
1H NMR (200 MHz, CDCl3, ppm):
4
7-6.5 (m, 4 × C6H4Me-4, 16H), 6.58 (t, J HH ) 1.5 Hz, HC6,
1H), 4.06 (d, CH2-aryl, 2H), 3.84 (s, MeO, 3H), 3.49 (s, MeO,
3H), 3.33 (q, 3J ) 7 Hz, CH2Me, 2H), 2.22 (s, Me C6H4, 6H),
2.27 (s, Me C6H4, 6H), 1.15 (t, MeCH2, 3H). 13C{1H} NMR (50
MHz, CDCl3, ppm): 184.5 (CdO), 160.5, 153.3, 151.8, 147.8,
142.0, 140.6, 136.9, 136.7, 132.1, 131.2, 129.7 (CH), 128.71
(CH), 128.66 (CH), 128.57 (CH), 127.1 (CH), 69.6 (C spiro),
67.2 (CH2), 66.8 (CH2), 60.8 (MeO), 60.2 (MeO), 21.3 (Me-C6H4),
21.1 (Me-C6H4), 15.1 (MeCH2). Anal. Calc for C43H42O4: C,
82.93; H, 6.80. Found: C, 82.74; H, 7.04. Mass spectrum:
m/ z (% abundance) 623 (M+ + 1, 15), 622 (M+, 29) 195 (31),
149 (27), 121 (15), 119 (100), 115 (11), 105 (26), 92 (10), 91
(41), 59 (22). Single crystals of 12c were obtained by cooling
saturated solutions of 12c in a mixture of diethyl ether and
n-hexane.
Rea ction of 4 w ith MeO2CCtCCO2Me. Syn th esis of
11. Complex 4 (100 mg, 0.21 mmol), Tl(CF3SO3) (73 mg, 0.21
mmol), and MeO2CCtCCO2Me (59 mg, 0.21 mmol) were
reacted in CH2Cl2 (6 cm3) for 1 h. The TlCl was filtered off,
and the filtrate was concentrated to ca. 2 cm3. Addition of
diethyl ether resulted in the precipitation of yellow 11.
Yield: 121 mg, 79%. Mp: 125 °C. ΛM (acetone): 120 Ω-1 cm2
mol-1. IR (Nujol): ν(CO) 1716, 1706 cm-1
.
1H NMR (300 MHz,
CDCl3, ppm): 6.98 (s, HC6, 1H), 4.62, 4.09 (AB system, 2J AB
)
9 Hz, CH2-aryl, 2H), 4.2-4.1 (m, CH2Me, 2H), 3.96 (s, MeO,
3H), 3.93 (s, MeO, 3H), 3.91 (s, MeO, 3H), 3.87 (s, CO2Me, 3H),
3.70 (s, CO2Me, 3H), 2.85 (s, MeN, 3H), 2.55 (s, MeN, 3H), 2.50
(s, MeN, 3H), 2.12 (s, MeN, 3H), 1.53 (“t”, 3J HH ) 7 Hz, MeCH2,
3H), 2.15-2.36 and 2.5-2.7 (multiplets of tmeda CH2, ob-
scured). 13C{1H} NMR (50 MHz, CDCl3, ppm): 170.4 (CdO),
168.2 (CdO), 161.6, 153.8, 151.1, 143.6, 129.7, 129.5, 126.3,
111.0 (CH-aryl), 75.9 (CH2), 75.0 (CH2), 65.0 (MeO), 61.0
(MeO), 60.8 (MeO), 58.1 (CH2), 56.6 (Me), 55.1 (CH2), 52.2 (Me)
52.1 (Me), 50.0 (Me), 49.4 (Me), 47.0 (Me), 15.6 (MeCH2). Anal.
Calc for C25H39N2F3O11PdS: C, 40.62; H, 5.32; N, 3.79; S, 4.34.
Found: C, 39.61; H, 5.31; N, 4.08; S, 4.34. Single crystals of
11 were obtained by liquid diffusion of diethyl ether into a
solution of 11 in acetone.
Rea ction of 5 w ith MeO2CCtCCO2Me. Syn th esis of
13. Complex 5 (100 mg, 0.19 mmol), MeO2CCtCCO2Me (54
mg, 0.38 mmol), and Tl(CF3SO3) (67 mg, 0.19 mmol) were
mixed in CH2Cl2 (6 cm3) and stirred for 1 h. The suspension
was filtered over Celite, the filtrate concentrated, and diethyl
ether added giving a precipitate of yellow 13. Yield: 134 mg,
76%. Mp: 183 °C. IR (Nujol): ν(CO) 1720 (s, br), 1700 (s, br)
cm-1. ΛM (acetone): 124 Ω-1 cm2 mol-1 1H NMR (200 MHz,
.
CDCl3, ppm): 9.5-9.4, 8.9-8.7, 7.9-7.0 (m, py, 10H), 6.95 (s,
HC6, 1H), 4.54, 4.37 (AB system, 2J AB ) 13 Hz, CH2-aryl, 2H),
4.02 (s, MeO, 3H), 3.89 (s, MeO, 3H), 3.80 (s, MeO, 3H), 3.6-
3.4 (m, CH2Me, 2H), 3.59 (s, CO2Me, 3H), 3.46 (s, CO2Me, 3H),
3.25 (s, CO2Me, 3H), 3.03 (s, CO2Me, 3H), 1.23 (“t”, 3J d 7 Hz,
MeCH2, 3H). 13C{1H} NMR (75 MHz, CDCl3, ppm): 170.7
(CdO), 168.9 (CdO), 166.2 (CdO), 160.4 (CdO), 155.2, 154.2
(CH-py), 152.9 (CH-py), 152.8, 138.7, 138.5 (CH-py), 138.4 (CH-
py), 137.5, 134.6, 124.6 (CH-py), 124.5 (CH-py), 121.7, 120.4,
117.5, 105.7 (CH-aryl), 69.1 (CH2), 66.0 (CH2), 60.3 (MeO), 59.2
(MeO), 56.0 (MeO), 52.6 (CO2Me), 52.2 (CO2Me), 52.0 (CO2Me),
Rea ction of 4 w ith EtCtCEt. Syn th esis of th e Sp ir o
Com p ou n d 12a . Complex 4 (100 mg, 0.21 mmol), Tl(CF3SO3)
(73 mg, 0.21 mmol), and EtCtCEt (50 mg, 0.61 mmol) were
reacted in CH2Cl2 for 24 h. The suspension was filtered over
anhydrous MgSO4, and the filtrate was concentrated and
chromatographed. Elution with diethyl ether-hexane (1:1)
rendered pale yellow 12a . Yield: 31 mg, 39%. Mp: 39 °C. IR
(Nujol): ν(CO) 1640 (br), 1690-1730 (br) cm-1
.
1H NMR (200
4
MHz, CDCl3, ppm): 6.61 (t, J HH ) 1.5 Hz, HC6, 1H), 3.89 (s,
MeO, 3H), 3.75 (s, MeO, 3H), 3.56 (d, CH2-aryl, 2H), 3.34 (q,
3J HH ) 7 Hz, MeCH2O, 2H), 2.4-1.7 (m, 4 × CH2Me, 8H), 1.15
(t, MeCH2O, 3H), 1.08 (t, 3J HH ) 7.5 Hz, 2 × MeCH2, 6H), 0.96
51.7 (CO2Me), 15.2 (MeCH2). Anal. Calc for C35H39N2F3O15
-
PdS: C, 45.54; H, 4.26; N, 3.03; S, 3.47. Found: C, 45.52; H,

28 Organometallics, Vol. 15, No. 1, 1996
Vicente et al.
Ta ble 1. Sp ecific Cr ysta llogr a p h ic Deta ils for Com p ou n d s 6, 11, 12c, a n d 13
compound
6
11
12c
13
formula
Mr
C40H40ClN2O8PPd
849.56
C25H39F3N2O11PdS
739.04
C43H42O4
622.77
C35H39F3N2O15PdS
923.14
cryst. habit
cryst size/mm
system
space group
cell consts
a/Å
yellow tablet
0.45 × 0.35 × 0.3
monoclinic
P21/c
yellow tablet
0.6 × 0.6 × 0.2
monoclinic
P21
colorless prism
0.58 × 0.36 × 0.18
monoclinic
C2/c
colorless tablet
0.38 × 0.36 × 0.12
orthorhombic
P212121
13.2936(14)
13.5928(12)
20.949(2)
92.462(8)
3782.0
4
1.492
0.66
1744
11.093(5)
11.069(5)
12.679(6)
90.54(4)
1556.8
2
1.577
0.74
760
36.542(4)
10.4546(14)
18.341(2)
94.764(6)
6982.8
8
1.185
0.075
2656
10.132(2)
19.078(3)
20.198(3)
90
3904.4
4
1.570
0.62
1888
173
b/Å
c/Å
â/deg
V/Å3
Z
Dx/Mg m-3
µ/mm-1
F(000)
T/K
173
143
173
2θmax/deg
no. of reflns
unique reflns
Rint
50
8197
6645
0.031
482
50
4121
3893
0.028
398
50
6224
6124
0.021
432
50
6356
6041
0.036
518
no. of params
no. of restraints
wR(F2), all reflns
R(F), F > 4σ(F)
S
407
310
440
456
0.079
0.036
0.91
0.067
0.027
1.08
0.46
-0.05(2)
0.086
0.039
0.78
0.073
0.049
0.80
0.46
-0.04(3)
max ∆F/e Å-3
Flack x param
0.55
0.19
4.17; N, 3.25; S, 3.39. Single crystals of 13 were obtained by
liquid diffusion of n-hexane into a solution of 13 in CDCl3.
Rea ction of Com p lex 10 w ith P P h 3. Syn th esis of 14.
Complex 10 (100 mg, 0.13 mmol) and PPh3 (34 mg, 0.13 mmol)
were reacted in CH2Cl2 for 12 h. Concentration of the solution
and addition of diethyl ether resulted in the precipitation of
yellow 14. Yield: 93 mg, 70%. Mp: 184 °C. ΛM (acetone):
Resu lts a n d Discu ssion
Syn t h esis of t h e Ar ylm er cu r y a n d -p a lla d iu m
Com p ou n d s. The reaction of 3,4,5-trimethoxybenzyl
chloride with mercury(II) acetate in ethanol results not
only in the desired mercuration process but also in the
substitution of the chloro atom by an ethoxy group from
the solvent. Pouring the alcoholic mixture into aqueous
NaCl affords [Hg(Ar)Cl] (1) (see Scheme 2). 1 can be
symmetrized to [Hg(Ar)2] (2) by reacting 1 with (NMe4)-
Cl, exploiting the low solubility of the resulting (NMe4)-
[HgCl3] (see Scheme 2). Compound 2 reacts with
Na2[PdCl4] in acetone/water mixtures giving solutions
that, after removal of acetone, lead to precipitation of 1
and an aqueous solution containing an arylpalladium
complex. A similar behavior was observed with the
6-formylaryl analogue of 2, where extraction of the
aqueous solution with CH2Cl2 gave an orthopalladated
complex resulting from a rearrangement process.6 How-
ever, in the present case, attempts to extract organo-
palladium species from the aqueous solution cause
decomposition to metallic palladium. Nevertheless,
addition to these aqueous solutions of 2,2′-bipyridine
(bpy) or N,N,N′,N′-tetramethylethylenediamine (tmeda)
or pyridine (py), and further extraction with CH2Cl2,
permit the isolation of the compounds [Pd(Ar)Cl(bpy)]
(3), [Pd(Ar)Cl(tmeda)] (4), or trans-[Pd(Ar)Cl(py)2] (5),
respectively, from the organic layer (Scheme 2). Though
the nature of the complex(es) present in these aqueous
solutions is unknown, it is clear from our results that
they behave as sources of “Pd(Ar)Cl”. As far as we are
aware, only two palladium complexes containing an
ROCH2-aryl ligand have previously been reported.15
It is possible to prepare new palladium complexes
from 3-5. Thus, the reaction of 3 with PPh3 and
NaClO4 leads to [Pd(Ar)(bpy)(PPh3)]ClO4 (6), whereas
125 Ω-1 cm2 mol-1 1H NMR (200 MHz, CDCl3, ppm): 9.3-
.
6.7 (5 m, bpy, PPh3, 2 Ph, 33H), 6.68 (s, HC6, 1H), 4.35, 3.44
2
(AB system, J AB ) 10 Hz, CH2-aryl, 2H), 3.92 (s, MeO, 3H),
3.35-3.12 (m, CH2Me, 2H), 3.20 (s, MeO, 3H), 2.72 (s, MeO,
3H), 1.13 (“t”, 3J ) 7 Hz, MeCH2, 3H). 13C{1H} NMR (75 MHz,
CDCl3, ppm): 156-123 (PPh3, 2Ph, bpy), 108.2 (CH-aryl), 75.7
(CH2), 66.3 (CH2), 60.0(MeO), 58.8 (MeO), 56.0 (MeO), 15.2
(MeCH2). 31P{1H} NMR (121.5 MHz, CDCl3, ppm): 32.8.
Anal. Calc for C54H50N2ClO8PPd: C, 63.28; H, 4.91; N, 2.73.
Found: C, 63.28; H, 5.25; N, 2.81.
Cr ysta l Str u ctu r e An a lyses. Crystal data are presented
in Table 1. Data collection: Data for 6, 12c, and 13 were
collected with Mo KR radiation on a Siemens P4 diffractometer
(11; Stoe STADI-4) equipped with an LT-2 low-temperature
device. Scan type ω was used (11; ω/θ). Cell constants were
refined from setting angles of ca. 60 reflections in the 2θ range
10-25° (11; (ω angles, 2θ 20-23°). Structure solution: Direct
methods (12c, 13) or heavy-atom method (6, 11). Structure
refinement: Anisotropic refinement on F2,12 H atoms as rigid
methyls or with a riding model, weighting schemes w-1
)
2(F2) + (aP)2 + bP, where 3P ) (2Fc + Fo2) and a and b
are constants optimized by the program. A variety of re-
straints were applied to light-atom displacement parameters
(DELU) and aromatic rings (FLAT, SAME). Special features
of refinement: For 11 and 13 the absolute structure was
determined by an x refinement.13 For 11 the origin was fixed
in terms of a weighted sum of coordinates.14 For 12 the ethyl
group C(51)/(52) was disordered over two sites. Final atomic
coordinates are given in Tables 2-5, with selected bond
lengths and angles in Tables 6-9.
2
(12) Sheldrick, G. M. SHELXL-93, a program for refining crystal
structures, University of Go¨ttingen, 1993.
(13) Flack, H. D. Acta Crystallogr. 1983, A39, 876.
(14) Flack, H. D.; Schwarzenbach, D. Acta Crystallogr. 1988, A44,
499.
(15) Brown, J . M.; Perez-Torrente, J . J .; Alcock, N. W.; Clase, H. J .
Organometallics 1995, 14, 207.

Pd-Assisted Formation of C-C Bonds
Organometallics, Vol. 15, No. 1, 1996 29
Ta ble 2. Atom ic Coor d in a tes (×104) a n d
Equ iva len t Isotr op ic Disp la cem en t P a r a m eter s
(Å2 × 103) for 6a
Ta ble 3. Atom ic Coor d in a tes (×104) a n d
Equ iva len t Isotr op ic Disp la cem en t P a r a m eter s
(Å2 × 103) for 11a
x
y
z
U(eq)
x
y
z
U(eq)
Pd
P
C(1)
C(2)
C(3)
C(4)
C(5)
C(6)
O(1)
O(2)
O(3)
O(4)
C(7)
C(8)
C(9)
C(10)
C(01)
C(02)
N(1)
C(11)
C(12)
C(13)
C(14)
C(15)
C(16)
C(17)
C(18)
C(19)
C(20)
N(2)
C(21)
C(22)
C(23)
C(24)
C(25)
C(26)
C(31)
C(32)
C(33)
C(34)
C(35)
C(36)
C(41)
C(42)
C(43)
C(44)
C(45)
C(46)
Cl
7829.8(2)
6992.1(7)
7590(3)
8268(3)
8178(3)
7396(3)
6718(3)
6813(3)
9004(2)
8862(2)
7352(2)
5246(2)
9995(3)
8666(3)
6496(3)
6082(3)
4507(3)
4815(4)
8545(2)
8753(3)
9226(3)
9487(3)
9274(3)
8801(2)
8542(2)
8667(3)
8445(3)
8104(3)
7974(3)
8173(2)
7614(3)
7096(3)
7615(4)
8656(4)
9181(3)
8660(3)
6780(3)
7291(3)
7111(3)
6431(3)
5918(3)
6093(3)
5731(3)
5563(3)
4625(3)
3851(3)
3994(3)
4938(3)
8356.0(8)
8552(3)
7624(3)
7975(3)
9260(2)
3285.0(2)
3014.1(7)
1857((2)
1171(3)
169(3)
5405.1(1)
6304.0(4)
5220.4(15)
5486.7(15)
5349((2)
4941((2)
4670(2)
22.0(1)
25.1(2)
25.2(8)
26.4(8)
27.9(8)
31.3(8)
29.5(8)
26.1(8)
33.5(6)
36.2(6)
43.7(7)
46.3(7)
49.2(12)
47.0(11)
44.3(10)
37.9(9)
58.0(12)
80(2)
23.8(6)
29.7(8)
31.2(9)
35.1(9)
30.2(8)
21.5(7)
22.8(7)
30.7(8)
35.8(9)
31.1(9)
28.8(8)
22.4(6)
30.8(8)
44.5(10)
57.3(12)
53.4(12)
39.2(9)
32.5(9)
28.4(8)
35.1(9)
45.7(11)
46.8(11)
41.6(10)
34.5(9)
29.1(8)
38.0(9)
48.4(11)
52.9(12)
51.1(12)
39.6(9)
39.6(2)
103.2(15)
91.3(13)
91.5(13)
75.7(11)
Pd
C(1)
C(2)
C(3)
C(4)
C(5)
C(6)
C(7)
7905.0(2)
6291(3)
5469(3)
5745(3)
5773(3)
6136(3)
6419(3)
6331(3)
6023(3)
6009(3)
6017(3)
4690(6)
4255(3)
3027(4)
4415(4)
7331(4)
7076(4)
7144(4)
7066(4)
10423(3)
9779(4)
10017(3)
9319(4)
7973(4)
9199(4)
9540(3)
8749(3)
7175(2)
5124(3)
6525(3)
4218(2)
3392(2)
5510(2)
6209(2)
6781(2)
9660.2(9)
10471(3)
8750(3)
10202(3)
8809(4)
8212(3)
7984(3)
9506(3)
5002.0(3)
4798(4)
5650(4)
6559(4)
7789(4)
8629(4)
8257(4)
7048(4)
6198(4)
4886(5)
3734(4)
2083(6)
5735(4)
5148(8)
8875(4)
10161(5)
8735(5)
3025(4)
2564(4)
5723(5)
6344(5)
4590(4)
6642(5)
6358(5)
4545(5)
5513(4)
5588(4)
4347(3)
3066(3)
3476(4)
5227(3)
6189(3)
8145(3)
9845(3)
9130(3)
6541.9(12)
6132(4)
7378(4)
6832(4)
5183(6)
4771(4)
5391(3)
4301(3)
7759.5(2)
7052(3)
7272(3)
8110(3)
7878(3)
8621(3)
9653(3)
9903(3)
9144(3)
9444(2)
6376(3)
6152(5)
6775(3)
5323(4)
6786(4)
7906(3)
11386(3)
9216(3)
10321(3)
7695(3)
6784(3)
9288(3)
9152(3)
5697(3)
5793(3)
8548(2)
6410(2)
9163(2)
6796(2)
5580(2)
5818(2)
7188(2)
6867(2)
8375(2)
10334(2)
2815.2(8)
3626(3)
3159(3)
1831(3)
2500(3)
3332(2)
1741(2)
2150(3)
19.3(1)
20.9(10)
20.0(8)
20.5(8)
20.7(8)
25.1(8)
22.9(8)
23.9(8)
20.5(8)
21.5(8)
26.1(9)
60(2)
-150(3)
517(3)
1517(2)
1481(2)
-507(2)
-1150(2)
1772(2)
1478(3)
-805(3)
-1524(3)
2253(3)
2433(4)
2844(4)
3524(2)
2828(3)
3035(3)
3990(3)
4711(3)
4466(2)
5198(3)
6196(3)
6853(3)
6477(3)
5477(3)
4830(2)
3650(3)
4160(3)
4661(3)
4651(3)
4130(3)
3631(3)
1778(3)
1429(3)
486(3)
4806(2)
5925.1(11)
5599.8(12)
4848.8(13)
4220.0(13)
5675(2)
6234(2)
4504(2)
4509(2)
3941(2)
3316(2)
4541.8(12)
4115(2)
3555(2)
3435(2)
C(8)
C(9)
C(10)
C(11)
C(12)
C(13)
C(14)
C(15)
C(16)
C(17)
C(18)
C(19)
C(20)
C(21)
C(22)
C(23)
C(24)
N(1)
N(2)
O(1)
O(2)
O(3)
O(4)
O(5)
O(6)
O(7)
O(8)
S
23.3(9)
56(2)
36.5(11)
39.6(12)
33.2(10)
26.5(9)
33.0(10)
33.0(11)
33.5(10)
30.7(10)
35.0(10)
35.1(10)
32.8(10)
25.3(7)
25.7(7)
19.7(6)
35.9(7)
40.3(8)
33.6(9)
31.2(7)
27.0(6)
31.7(7)
29.0(7)
33.8(3)
47.9(9)
48.9(9)
52.1(10)
40.7(13)
63.6(11)
59.0(9)
67.3(10)
3869(2)
4421.2(14)
4913.4(15)
4825(2)
5307(2)
5871(2)
5923(2)
5454.2(12)
6973(2)
7424(2)
7914(2)
7949(2)
7512(2)
7023(2)
6602.2(15)
7143(2)
7355(2)
7038(2)
6497(2)
6278(2)
6232(2)
5845(2)
5798(2)
6133(2)
6517(2)
6575(2)
7795.5(4)
8018(2)
7297.2(15)
8308(2)
O(97)
O(98)
O(99)
C(99)
F(1)
-111(3)
219(3)
1162(3)
3546(3)
4360(3)
4802(3)
4435(4)
3623(3)
3183(3)
7537.0(7)
8503(3)
7571(3)
6997(3)
7093(2)
F(2)
F(3)
a
U(eq) is defined as one third of the trace of the orthogonalized
Uij tensor.
Rea ction s of 3-5 w ith Alk yn es. We have carried
out a study of the reactions of these three palladium
complexes with various alkynes, in order to determine
the influence of the nature of the ligands attached to
the metal and of the alkynes. The alkynes used were
EtCtCEt, PhCtCPh, 4-MeC6H4CtCC6H4Me-4, and
MeO2CCtCCO2Me, and the positive results are de-
picted in Schemes 3 and 4. The reactions not repre-
sented gave complex mixtures that we could not sepa-
rate. The reactions were carried out in the presence of
AgClO4 or Tl(CF3SO3) in order to remove the chloro
ligand and thus creating a coordinative vacancy; oth-
erwise untractable mixtures were obtained.
O(5)
O(6)
O(7)
O(8)
7600(2)
a
U(eq) is defined as one-third of the trace of the orthogonalized
Uij tensor.
reaction of 5 with AgClO4 in acetone results in the
elimination of the chloro ligand as AgCl and the
presumable formation of the cation [Pd(Ar)(acetone)-
(py)2]+. Filtration of the AgCl and addition of pyridine
afford [Pd(Ar)(py)3]ClO4 (7). The latter reacts at room
temperature with PPh3 to give a mixture of cis- and
trans-[Pd(Ar)(PPh3)(py)2]ClO4. If this mixture is re-
fluxed in acetone only, the cis isomer is isolated. The
formation of the trans isomer must be due to the greater
trans-effect exerted by the Ar ligand, while its trans-
formation into the cis compound can be explained by
the antisymbiotic effect, according to which PPh3 trans
to an aryl ligand is unfavorable.16 On heating the
process is thermodynamically controlled, giving cis-[Pd-
(Ar)(PPh3)(py)2]ClO4 (8).
The bpy complex 3 gives clear results only with
EtCtCEt and PhCtCPh (see Scheme 3). The former
gives rise to the π-allyl complex 9 whereas the latter
gives the monoinserted palladium complex 10 (see
Scheme 3). A similar result is obtained in the reaction
(16) Pearson, R. G. Inorg. Chem. 1973, 12, 712. Dehand, J .;
J ordanov, J .; Pfeffer M.; Zinsius, M. C. R. Acad. Sci., Ser. C 1975, 281,
651 Pfeffer, M.; Grandjean D.; Le Borgne, G. Inorg. Chem. 1981, 20,
4426. Arlen, C.; Pfeffer, M.; Bars, O.; Le Borgne, G. J . Chem. Soc.,
Dalton Trans. 1986, 359. Vicente, J .; Bermu´dez, M. D.; Carrio´n, F. J .
Inorg. Chim. Acta 1994, 220, 1.

30 Organometallics, Vol. 15, No. 1, 1996
Vicente et al.
Ta ble 4. Atom ic Coor d in a tes (×104) a n d
Equ iva len t Isotr op ic Disp la cem en t P a r a m eter s
(Å2 × 103) for 12ca
Ta ble 5. Atom ic Coor d in a tes (×104) a n d
Equ iva len t Isotr op ic Disp la cem en t P a r a m eter s
(Å2 × 103) for 13a
x
y
z
U(eq)
x
y
z
U(eq)
O(1)
O(2)
O(3)
O(4)
C(1)
C(2)
C(3)
C(4)
C(5)
C(6)
C(7)
C(8)
6839.8(4)
7117.0(4)
6709.6(4)
5628.1(4)
6361.4(5)
6104.4(5)
6125.3(5)
6382.3(5)
6526.7(5)
6678.2(5)
6802.1(5)
6597.2(5)
6256.1(5)
6144.5(5)
6965.2(7)
7446.7(6)
5793.0(6)
5767.4(8)
5556.4(9)
5863.5(5)
5946.1(6)
5718.7(6)
5401.0(6)
5315.7(6)
5539.0(6)
5154.8(7)
5924.9(5)
5999.7(6)
5804.4(6)
5528.3(6)
5457.7(6)
5655.5(6)
5313.3(7)
6462.3(5)
6526.1(5)
6607.3(6)
6625.6(6)
6559.0(6)
6479.2(5)
6722.2(6)
6836.2(5)
7165.0(6)
7462.0(6)
7444.0(5)
7122.0(6)
6822.7(6)
7759.9(6)
4617.0(13)
7162.0(14)
9060.5(13)
7256.2(14)
5337(2)
4334(2)
3247(2)
3417(2)
4613(2)
5676(2)
6876(2)
7960(2)
7679(2)
6488(2)
4640(2)
6875(3)
6199(2)
7523(2)
8592(3)
4655(2)
5679(2)
6011(2)
5346(2)
4334(2)
3995(2)
5707(3)
2036(2)
1373(2)
282(2)
5664.3(7)
5536.4(8)
6081.3(8)
7235.7(8)
37.7(4)
40.9(4)
43.3(4)
47.3(4)
23.7(4)
24.6(5)
25.6(5)
24.3(5)
23.2(5)
24.7(5)
26.8(5)
29.1(5)
27.9(5)
25.7(5)
54.6(7)
57.6(7)
38.2(6)
61.3(8)
95(1)
26.8(5)
38.1(6)
40.9(6)
36.3(5)
40.9(6)
34.6(5)
61.0(8)
26.6(5)
35.7(5)
41.5(6)
38.5(6)
44.0(6)
35.6(5)
59.4(8)
24.1(5)
28.8(5)
33.5(5)
32.1(5)
34.0(5)
29.9(5)
46.5(6)
24.8(5)
39.9(6)
42.4(6)
27.8(5)
36.8(6)
35.8(6)
39.3(6)
Pd
S
O(1)
O(2)
O(3)
O(4)
O(5)
O(6)
O(7)
O(8)
O(9)
O(10)
O(11)
O(12)
O(13)
O(14)
C(1)
C(2)
C(3)
C(4)
C(5)
C(6)
C(7)
C(8)
C(9)
C(10)
C(11)
C(12)
C(13)
N(2)
C(21)
C(22)
C(23)
C(24)
C(25)
N(1)
C(31)
C(32)
C(33)
C(34)
C(35)
C(41)
C(42)
C(43)
C(44)
C(45)
C(46)
C(47)
C(48)
C(49)
C(50)
O(15)
C(51)
C(52)
C(51′)
C(52′)
F(1)
6745.0(6)
8994(2)
5784(4)
3954(5)
5074(5)
4293(5)
7862(5)
7997(6)
6747(6)
8473(5)
7700(5)
9808(6)
9623(6)
6998(5)
5119(5)
2576(5)
5777(6)
5169(7)
3372(9)
5742(7)
5038(7)
3572(7)
6536(8)
7516(7)
8907(6)
6383(7)
7216(8)
9318(8)
8647(10)
8454(6)
8907(6)
10150(7)
10996(8)
10520(7)
9272(6)
5033(6)
3945(7)
2802(7)
2801(7)
3898(8)
5005(7)
5333(7)
5688(7)
4733(8)
3437(8)
3074(7)
4006(8)
7662(8)
5465(10)
1213(7)
3594(7)
2312(5)
1739(17)
2218(19)
2073(24)
890(25)
9738(6)
8046(7)
7897(8)
-260.1(3)
-1158.8(12)
-506(2)
-406(2)
1950(2)
893(2)
2498(2)
1594(2)
2618(2)
1949(3)
-861(3)
-756(3)
-1387(3)
711(2)
3332.8(3)
4178.9(12)
1739(3)
2361(2)
1929(2)
1670(3)
2806(2)
2099(2)
4302(3)
4050(2)
4093(2)
4635(3)
3608(3)
4668(2)
5586(2)
5420(2)
2658(3)
2186(3)
2055(3)
2581(3)
2035(4)
1139(3)
3006(4)
2640(4)
1702(4)
3654(4)
4024(4)
4412(4)
4652(6)
2980(2)
2386(3)
2173(3)
2569(4)
3173(4)
3371(4)
3645(3)
3798(3)
4010(4)
4068(4)
3910(4)
3699(3)
4085(3)
4627(4)
5060(3)
4984(3)
4471(3)
4024(3)
5293(4)
5400(4)
5327(4)
3488(4)
3551(3)
2926(6)
2755(10)
3127(13)
3164(16)
4778(3)
5202(3)
4292(4)
23.9(1)
41.6(6)
39.0(13)
33.0(13)
44(2)
45.0(14)
44(2)
37.9(14)
46.7(14)
35.7(14)
39(2)
72(2)
82(2)
40.6(14)
48.8(15)
41(2)
23(2)
24.0(15)
51(2)
23(2)
28(2)
48(2)
25(2)
29(2)
44(2)
25(2)
33(2)
63(3)
61(3)
21.0(13)
28(2)
37(2)
39(2)
39(2)
28(2)
25.1(15)
28(2)
40(2)
44(2)
41(2)
32(2)
24(2)
27(2)
6359.7(10)
5984.8(10)
6383.7(10)
7041.7(10)
7044.6(10)
5921.7(10)
5865.6(10)
6133.6(10)
6455.9(10)
6577.3(10)
4945.6(12)
5978.9(13)
6921.8(12)
7957.2(13)
8258(2)
5320.6(10)
4878.4(11)
4264.7(11)
4069.5(11)
4511.4(12)
5123.5(11)
3397.7(12)
6193.1(11)
5568.3(11)
5361.0(12)
5755.4(13)
6383.9(13)
6607.0(11)
5516.4(15)
7614.5(10)
7441.9(11)
7985.8(11)
8720.5(11)
8889.8(11)
8348.6(11)
9314.0(11)
7518.5(10)
7632.3(12)
8062.8(12)
8389.1(10)
8261.9(11)
7838.9(11)
8873.7(11)
C(9)
C(10)
C(11)
C(12)
C(13)
C(14)
C(15)
C(21)
C(22)
C(23)
C(24)
C(25)
C(26)
C(27)
C(31)
C(32)
C(33)
C(34)
C(35)
C(36)
C(37)
C(41)
C(42)
C(43)
C(44)
C(45)
C(46)
C(47)
C(51)
C(52)
C(53)
C(54)
C(55)
C(56)
C(57)
188(3)
509(3)
284(4)
-238(4)
-1009(3)
972(3)
1324(4)
1187(4)
1481(4)
1933(4)
1992(3)
1587(4)
2113(4)
2434(4)
-1934(5)
113(2)
-174(2)
478(2)
-74(3)
96(4)
472(4)
677(4)
1564(2)
-1356(2)
2428(2)
1155(2)
265(2)
488(3)
-715(3)
-373(4)
-690(4)
-1403(4)
-1778(4)
-1422(4)
1295(4)
877(4)
617(4)
798(3)
1245(3)
1486(4)
851(5)
596(2)
1866(2)
2769(2)
-372(2)
5148(2)
4487(2)
4983(2)
6166(2)
6836(2)
6348(2)
6697(2)
31(2)
31(2)
24(2)
25(2)
70(3)
84(4)
47(2)
45(2)
68(2)
61(4)
122(7)
61(4)
122(7)
85(2)
a
U(eq) is defined as one third of the trace of the orthogonalized
-520(4)
658(4)
Uij tensor.
1991(4)
2206(3)
2482(7)
3080(9)
2871(12)
3114(13)
-2293(2)
-1797(3)
-2360(3)
of the tmeda complex 4 and MeO2CCtCCO2Me, giving
11. A depalladation process, giving the organic spiro-
cyclic compound 12a , is observed when 4 or 5 react with
EtCtCEt (12a ) (molar ratio e 1:2). Related compounds
are obtained by reacting 5 with diarylacetylenes RCtCR,
R ) Ph (12b) and To (C6H4Me-4) (12c). The alkyne
MeO2CCtCCO2Me reacts differently with 5, giving a
monoinserted complex when the molar ratio is 1:1 or
the diinserted complex 13 when this ratio is g2:1. The
monoinserted complex could not be obtained analytically
F(2)
F(3)
124(3)
165(4)
a
U(eq) is defined as one third of the trace of the orthogonalized
Uij tensor.
formation of spirocyclic compounds 12a -c. We have
proposed a reaction pathway in the synthesis of similar
spiro compounds starting from (6-acetyl-2,3,4-trimethox-
yphenyl)palladium complexes.1 Scheme 4 adapts such
a proposal to the synthesis of 12a -c and shows those
intermediates that we have isolated. Complexes 10 and
11 constitute models of the intermediate resulting from
the initial coordination of one alkyne and its insertion
into the arylic carbon-palladium bond (A in Scheme 4).
The formation of such monoinserted cyclometalated
complexes is well documented, although not with oxygen
pure, but its H and 13C NMR spectra clearly show the
presence of five MeO groups. Compounds 9-12 and 13
were also obtained even when an excess of the alkynes
was used.
The reactivity of 3-5 with alkynes seems to be erratic.
This is also the impression when the complete area of
the reactions between arylpalladium complexes and
alkynes is observed.8 However, our results are inter-
connected because compounds 9-11 and 13 can be
considered as models for the intermediates in the
1

Pd-Assisted Formation of C-C Bonds
Organometallics, Vol. 15, No. 1, 1996 31
Sch em e 2
Sch em e 3
and the palladium atom.8 This process requires that
the first alkyne inserted should change from the original
cis to trans geometry. Two different mechanisms have
been proposed for this isomerization. In the first (see
A f B f C f D in Scheme 5),8c the second alkyne
insertion is also cis (see B in Scheme 5), but a cis to
trans isomerization takes place to give the final isolated
complex (see D in Scheme 4). The assumption of an
equilibrium B h C h D is based on the observation that
some derivatives of these intermediates have a cis,cis
geometry.8q The second proposal (A f B′ f C′ f D)8j
assumes that the second insertion leads to a pallada-
cyclobutene intermediate (C′) that, after cleavage of the
first η1-alkene-Pd σ bond, gives finally the cis,trans-
butadienylpalladium complex. Our complex 13 is the
first example of a cis,cis di-insertion of an alkyne into
an arylpalladium bond, confirmed by its crystal struc-
ture (see below). Its isolation could be interpreted as
support for the first mechanistic proposal. However, it
is also possible that, in our case, no cis to trans
isomerization occurs because the driving force for such
isomerization is probably the E f Pd bond and, in our
case, the O f Pd could not exist (as in 13). In fact, a
cis,cis double insertion of alkynes into a Pd-Cl bond is
observed when starting from [PdCl2(NCPh)2].18 The
isolation of 13 and not the corresponding intermediates
(B in Scheme 4) in the synthesis of 9 or 12a -c could be
due to the greater stability of the cis-CRdCR-cis-
CRdCR(Ar) σ bond with Pd when R ) CO2Me. Thus,
when L ) py and R ) Ph, Et or L2 ) tmda and R) Et,
the organic spiro compounds 12a -c are obtained without
isolation of any intermediate. In contrast, intermedi-
ates 11, 13, and the monoinserted precursor of 13 are
obtained when R ) CO2Me. The ligand bpy also confers
special stability on intermediates and thus, for example,
no spontaneous depalladation is observed from 3, in-
termediates 9 and 10 being isolated instead.
as the heteroatom bonded to palladium.8c,d,k,o It is also
noteworthy that, whereas complexes 10 and 11 are
stable cyclometalated species with seven-membered
rings, it was not possible to isolate the supposedly more
favorable five-membered ring complexes with the Ar
group, since all our attempts to coordinate this oxygen
atom, for example, by reacting 3-5 with TlCF3SO3, led
to ill-defined complexes. It is probable that coordination
of the oxygen atom is prevented because of the repulsion
between the ortho MeO group and the cis ligand. As
far as we are aware, only one paper reports reactions
of palladacycles stabilized by an O f Pd bond with an
alkyne. However, in all cases monoinserted complexes
were obtained.17
The second step consists of the insertion of a second
alkyne to give a butadienyl derivative (B in Scheme 4).
Complexes of this type have previously been isolated
by the reaction of orthometalated palladium complexes,
Ar-[Pd], with alkynes R2C2. However, their structures
invariably show a [Pd]-cis-CRdCR-trans-CRdCR(Ar)
chain with an additional bond between the metal center
and the trans-CdC-π electron system (see D in Scheme
5). In addition, a third bond is established between a
donor atom (N or S) of some substituent of the Ar group
The third step may be ring contraction of the diin-
serted species B to give a (π-allyl) palladium complex
(17) Ossor, H.; Pfeffer, M.; J astrzebski, J . T. B. H.; Stam, C. H. Inorg.
Chem. 1987, 26, 1169.
(18) Maitlis, P. M. J . Organomet. Chem. 1980, 200, 161.

32 Organometallics, Vol. 15, No. 1, 1996
Vicente et al.
Sch em e 4
Sch em e 5. P r op osed Mech a n ism s for th e Secon d
In ser tion of a n Alk yn e in to a Cyclom eta la ted
P a lla d iu m Com p lex (E ) Nitr ogen or Su lfu r Don or
Moiety)
because only the product of the monoinsertion reaction
was obtained (see Scheme 1).1
We have unsuccessfully attempted to depalladate
complex 10 by treating it with PPh3, but even on
heating, the compound [Pd{cis-CPhdCPh(Ar)}(PPh3)-
(bpy)]ClO4 (14) (see Scheme 3) was isolated.
NMR Sp ectr a . As expected, the mercurials 1 and 2
and the palladium complexes 5 and 7 show a singlet at
1
4.4-5.0 ppm in their H NMR spectra assignable to the
benzyl CH2 protons. However, these protons appear as
an AB system in complexes 3, 4, 6, 8, and 14 because
rotation about the aryl carbon-palladium bond is
restricted at room temperature on the NMR time scale.
The same behavior has been noted previously.15 Such
a restriction is also responsible for the observation of
four singlets corresponding to the methyl groups of the
1
ligand tmda in complex 4, both in their H and 13C NMR
spectra.
containing the spiro framework (see C in Scheme 4),
such as the isolated complex 9. The C-C bond forma-
tion is facilitated by the relatively short distance
between both atoms (see below). The reaction between
The monoinserted complexes 10 and 11 also show the
presence of an AB system for the benzylic CH2 protons
in the 1H NMR spectra. This is the expected system
for such protons, the oxygen atom being rendered chiral
by its bonding to the palladium atom. If inversion, on
the NMR time scale, of the chirality around the oxygen
atom is assumed, the puckering of the ring could give
account for the diastereotopic nature of the CH2 protons.
Accordingly, the Me groups of the tmeda ligand in 11
[Pd{C6H{C(O)Me}-(-6-(OMe)3-2,3,4}(µ-Cl)]2 and diary-
lacetylenes was assumed to proceed through a similar
complex [Pd(η3-allyl)(µ-Cl)]2.1 We isolated the reaction
product of this intermediate with thallium triflate and
bpy, and its crystal structure revealed a species of a
nature similar to that proposed for 9 (see below). A
similar intermediate from reaction of diphenylacetylene
and orthopalladated 2-benzylpyridine has been isolated.8q
appear as four signals in the H and 13C NMR spectra.
1
Compound 13 in solution must retain the nonplanar
configuration observed in the solid state (see below)
because the benzylic CH2 protons also appear as an AB
system in its 1H NMR spectrum. However, in these
compounds with diasterotopic methylene protons, the
resonances corresponding to the Et protons have a
deceptively simple appearance because, instead of those
resonances expected for an ABX3 system, a quartet and
a triplet are observed for the CH2 and Me protons,
respectively.
We have proposed that formation of the keto group
and depalladation occur through reaction of C with
adventitious water, leading to intermediate D (see
Scheme 4) because using freshly distilled solvent, slow
decomposition is initially observed but rapidly stops.
The resulting solution remains unaltered, but addition
of water gives the spiro compound.1 We assume that
the same pathway is operative in the synthesis of
compounds 12a -c. The behavior of EtCtCEt toward
complexes 3-5 is different from that observed with the
related (6-acetyl-trimethoxyphenyl)palladium complex
X-r a y Str u ctu r a l Stu d ies. Compounds 6, 11, 12c,
and 13 have been studied by X-ray diffraction. The
cation of complex 6 (see Figure 1 and Tables 2 and 6)

Pd-Assisted Formation of C-C Bonds
Organometallics, Vol. 15, No. 1, 1996 33
F igu r e 3.
F igu r e 1.
Ta ble 7. Selected Bon d Len gth s (Å) a n d An gles
(d eg) for 11
Pd-C(1)
Pd-N(2)
Pd-O(1)
Pd-N(1)
C(1)-C(2)
C(2)-C(3)
C(3)-C(4)
C(3)-C(8)
2.007(3)
2.063(3)
2.092(3)
2.139(3)
1.343(6)
1.494(5)
1.393(6)
1.402(5)
C(8)-C(9)
C(9)-O(1)
C(17)-O(1)
S-O(99)
S-O(97)
S-O(98)
S-C(99)
1.501(7)
1.470(4)
1.466(5)
1.427(3)
1.433(3)
1.440(4)
1.818(6)
C(1)-Pd-N(2)
C(1)-Pd-O(1)
N(2)-Pd-N(1)
O(1)-Pd-N(1)
C(2)-C(1)-C(10)
C(2)-C(1)-Pd
C(10)-C(1)-Pd
C(1)-C(2)-C(12)
C(1)-C(2)-C(3)
C(12)-C(2)-C(3)
94.28(13)
C(4)-C(3)-C(8)
C(4)-C(3)-C(2)
C(8)-C(3)-C(2)
C(7)-C(8)-C(3)
C(7)-C(8)-C(9)
C(3)-C(8)-C(9)
O(1)-C(9)-C(8)
C(17)-O(1)-C(9)
C(17)-O(1)-Pd
C(9)-O(1)-Pd
118.1(4)
120.9(3)
121.0(4)
120.4(4)
118.9(3)
120.7(3)
108.7(3)
111.9(3)
113.2(2)
114.5(2)
89.43(13)
85.13(13)
91.58(12)
122.7(3)
115.6(3)
121.6(3)
124.9(4)
119.1(3)
116.0(3)
F igu r e 2.
Ta ble 8. Selected Bon d Len gth s (Å) a n d An gles
(d eg) for 12c
Ta ble 6. Selected Bon d Len gth s (Å) a n d An gles
(d eg) for 6
O(3)-C(8)
C(1)-C(6)
C(1)-C(10)
C(1)-C(2)
C(1)-C(5)
C(2)-C(3)
C(2)-C(21)
C(3)-C(4)
C(3)-C(31)
1.228(2)
1.505(3)
1.512(3)
1.532(2)
1.546(2)
1.350(2)
1.481(3)
1.477(3)
1.490(3)
C(4)-C(5)
C(4)-C(41)
C(5)-C(51)
C(6)-C(7)
C(7)-C(8)
C(8)-C(9)
C(9)-C(10)
C(10)-C(13)
1.356(2)
1.486(3)
1.478(3)
1.341(3)
1.465(3)
1.453(3)
1.335(3)
1.508(3)
Pd-C(1)
Pd-N(1)
Pd-N(2)
2.002(3)
2.104(3)
2.151(3)
Pd-P
2.2589(9)
1.404(4)
1.436(5)
O(4)-C(10)
O(4)-C(01)
C(1)-Pd-N(1)
N(1)-Pd-N(2)
C(1)-Pd-P
93.32(11)
77.73(10)
85.57(9)
N(2)-Pd-P
C(10)-O(4)-C(01)
103.33(7)
113.6(3)
shows a distorted square-planar coordination (mean
deviation of 5 atoms 0.02 Å) of the ligands bpy, Ar, and
PPh3 around the metal center. The maximum distor-
tions correspond to the N(1)-Pd-N(2) [77.73(10)°]
(narrow bite of the bpy ligand) and N(2)-Pd-P [103.33-
(7)°] angles, respectively. The aryl ligand (with its
immediate substituents) is almost planar (mean devia-
tion 0.02 Å) and perpendicular (82°) to the coordination
plane. The greater trans influence of aryl group with
respect to PPh3 causes Pd-N(2) [2.151(3) Å] to be longer
than Pd-N(1) [2.104(3) Å]. The Pd-C(1) [2.002(3) Å]
and Pd-P [2.151(3) Å] bond distances are normal.19
There is a short contact of 3.08 Å between the palladium
atom and the perchlorate oxygen O(1).
C(6)-C(1)-C(10)
C(6)-C(1)-C(2)
C(10)-C(1)-C(2)
C(6)-C(1)-C(5)
C(10)-C(1)-C(5)
113.4(2)
C(2)-C(1)-C(5)
O(3)-C(8)-C(9)
O(3)-C(8)-C(7)
C(9)-C(8)-C(7)
102.3(2)
121.7(2)
121.0(2)
117.3(2)
113.1(2)
110.4(2)
106.4(2)
110.7(2)
nected to the palladium atom through the oxygen O(1)
of the ethoxide group. The coordination deviates sig-
nificantly from planar; the angle between the planes
Pd,C(1),N(2),O(1)/Pd,N(1),N(2),O(1) is 11°. Here too the
carbon donor atom has the greater trans influence as
shown by the longer Pd-N(1) bond distance [2.139(3)
Å] than Pd-N(2) [2.063(3) Å]. Coordination to pal-
ladium of the oxygen atom of the ethoxide group leads
to a slight increase of both C-O bonds [1.466(5), 1.470-
(4) Å] and a decrease of the C-O-C bond angle [111.9-
(3)°] with respect to the corresponding values in complex
6 [1.436(5), 1.404(4) Å, 113.6(3)°].
The cation of 11 (see Figure 2 and Tables 3 and 7)
shows a puckered seven-membered metallacycle formed
by the monoinserted alkyne and the aryl moiety con-
The structure of 12c (see Figure 3 and Tables 4 and
8) consists of two ring systems, 2,3,4,5-tetra-para-
(19) Orpen, A. G.; Brammer, L.; Allen, F. H.; Kennard, O.; Watson,
D. G.; Taylor, R. J . Chem. Soc., Dalton Trans. 1989, S1.

34 Organometallics, Vol. 15, No. 1, 1996
Vicente et al.
Ta ble 9. Selected Bon d Len gth s (Å) a n d An gles
(d eg) for 13
Pd-C(1)
Pd-N(2)
Pd-N(1)
Pd-O(9)
S-O(11)
S-O(9)
1.975(7)
2.003(5)
2.040(6)
2.147(5)
1.388(6)
1.440(5)
1.455(6)
1.321(9)
C(1)-C(2)
C(4)-C(5)
C(4)-C(7)
C(7)-C(10)
C(7)-C(8)
C(10)-C(41)
C(10)-C(11)
1.511(9)
1.475(9)
1.526(9)
1.333(8)
1.508(9)
1.483(9)
1.510(9)
S-O(10)
C(1)-C(4)
C(1)-Pd-N(2)
C(1)-Pd-N(1)
N(2)-Pd-O(9)
N(1)-Pd-O(9)
C(4)-C(1)-C(2)
C(4)-C(1)-Pd
C(2)-C(1)-Pd
C(1)-C(4)-C(5)
89.8(2)
90.9(2)
93.1(2)
C(1)-C(4)-C(7)
C(5)-C(4)-C(7)
C(10)-C(7)-C(8)
C(10)-C(7)-C(4)
C(8)-C(7)-C(4)
C(7)-C(10)-C(41)
C(7)-C(10)-C(11)
C(41)-C(10)-C(11)
123.5(6)
112.7(6)
118.1(7)
125.9(8)
115.8(6)
127.1(8)
121.4(8)
111.1(6)
86.3(2)
124.8(6)
128.0(5)
106.9(5)
123.5(7)
situation could also exist in the intermediates B in
Scheme 4, thus facilitating the formation of the spiro
intermediate C.
F igu r e 4.
Sch em e 6
Con clu sion s. We have shown that [Hg(Ar)2] (Ar )
C6H(CH2OEt)-6-(OMe)3-2,3,4), obtained from 3,4,5-tri-
methoxybenzyl chloride and mercury(II) acetate in
ethanol, reacts with K2[PdCl4] giving water-soluble
arylpalladium species from which neutral and cationic
complexes can be isolated. By reacting some of these
species with alkynes, it is possible to isolate spiro
compounds and model complexes of their synthetic
intermediates.
tolylcyclopenta-2,4-diene and 2,3-dimethoxy-6-(ethoxym-
ethylene)cyclohexa-2,5-dien-4-one, with a common spiro
carbon atom C(1). The bond lengths and angles are
similar to those found in the 1-hydroxyethyl derivative
(see B in Scheme 6), which we prepared1 from the
phenyl derivative (A in Scheme 6) related to 12c.
The structure of 13 (see Figure 4 and Tables 5 and 9)
shows a slightly distorted square-planar coordination
(mean deviation 0.05 Å) of the ligands around the metal
center, the pyridine molecules being mutually trans. The
butadienyl ligand forms a spiral chain that places the
carbon atom initially bonded to palladium, C(41), near
the carbon bonded to palladium, C(1) (3.50 Å). This
Ack n ow led gm en t. We thank the Direccio´n General
de Investigacio´n Cient´ıfica y Te´cnica (Grant PB92-0982-
C) and the Fonds der Chemischen Industrie for financial
support. R.F.-d-B. is grateful for a grant from Ministerio
de Educacio´n y Ciencia, and M.C.R.d.A., for a stipen-
dium from the Alexander-von-Humbolt-Stiftung.
Su p p or tin g In for m a tion Ava ila ble: Tables giving crys-
tal data and details of the structure determination, complete
atom coordinates and U values, bond lengths and angles, and
anisotropic displacement coefficients (32 pages). Ordering
information is given on any current masthead page.
OM950603X