Aminomethyl and aminoacetyl complexes of palladium(II), platinum(II), iron(II) and rhenium(I) with N-phthaloyl as amino protecting group and mechanistic studies on the palladium-catalyzed amidocarbonylation

Article abstract of DOI:10.1002/ejic.200300617

New aminomethyl and aminoacetyl complexes with N-phthaloyl as the amino protecting group were synthesised by oxidative addition of N-phthaloylmethyl or -acetyl halide to carbonylmetallates or to Pd(PPh₃)₄ or [Pt(C₂H₄)(PPh₃)₂] to give [Re{C(O)CH₂N-phthaloyl}(CO)₅] (1), [FeCp(CH ₂N-phthaloyl)(CO)₂] (2), [FeCp{C(O)CH₂N- phthaloyl}(CO)₂] (3), trans-[PdBr(CH₂N-phthaloyl)(PPh ₃)₂] (4) and trans-[Pd{C(O)CH₂N-phthaloyl}(X) (PPh₃)₂] (X = Br, Cl; 5, 6). The bis(phosphane) complexes [Pd(CH₂N-phthaloyl)(X)-(R₂PCH₂CH ₂PR₂)] and [Pd{C(O)CH₂N-phthaloyl}(X)-(R ₂PCH₂CH₂PR₂)] (X = Cl, Br; R = Ph, C₆H₁₁) 8-13 were obtained by ligand exchange from 4, 5 or 6 with the corresponding bis(phosphanes). Halide abstraction from 4, 5, 6, 10, 11 or 12 gives the cationic complexes 14 and 15 with formation of a five-membered chelate ring which includes one carbonyl atom of the phthaloyl group. The reaction of 6 with the tridentate ligand PhP(CH₂CH ₂PPh₂)₂ affords the five-coordinate complex 16 and from [Pt(C₂H₄)(PPh₃)₂] and organic halides the platinum(II) complexes trans-[Pt(CH₂N-phthaloyl) (Cl)(PPh₃)₂] (17) and [PtC(O)CH(CH₂Ph)N- phthaloyl(Cl)(PPh₃)₂] (18) were isolated. The structures of 2, 11, 14, 15 and 16 were determined by single-crystal X-ray analysis. The mechanism of the palladium-catalysed amidocarbonylation was studied using phthalimide, formaldehyde and CO as a model system which gives N-phthaloylglycine in good yield. The proposed elementary steps in the palladium-catalysed amidocarbonylation could be verified by use of the possible intermediates phthaloyl-NCH₂OH and phthaloyl-NCH₂Br as substrates, by oxidative addition of phthaloylmethyl bromide to Pd⁰, by insertion of CO into the palladium-carbon-bond of 4 and 8 with formation of 5 or 9, respectively, and by use of the isolated possible intermediates 4, 5 and 14 as catalysts. Thus, all crucial steps of the palladium-catalysed amidocarbonylation with the model system phthalimide/formaldehyde/CO have been verified for the first time. Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004.

Full text of DOI:10.1002/ejic.200300617

FULL PAPER
Aminomethyl and Aminoacetyl Complexes of Palladium(II), Platinum(II),
Iron(II) and Rhenium( ) with N-Phthaloyl as Amino Protecting Group and
I
Mechanistic Studies on the Palladium-Catalyzed Amidocarbonylation
Armin Enzmann,[a] Markus Eckert,[b] Walter Ponikwar,[a][‡] Kurt Polborn,[a][‡]
Stefan Schneiderbauer,[a][‡] Matthias Beller,*[b] and Wolfgang Beck*[a]
Dedicated to Dr. Hachiro Wakamatsu
Keywords: Amidocarbonylation / Iron / Palladium / Platinum / Rhenium
New aminomethyl and aminoacetyl complexes with N-
phthaloyl as the amino protecting group were synthesised by
oxidative addition of N-phthaloylmethyl or -acetyl halide to
carbonylmetallates or to Pd(PPh3)4 or [Pt(C2H4)(PPh3)2] to
phthaloyl)(Cl)(PPh3)2] (17) and [PtC(O)CH(CH2Ph)N-
phthaloyl(Cl)(PPh3)2] (18) were isolated. The structures of 2,
11, 14, 15 and 16 were determined by single-crystal X-ray
analysis. The mechanism of the palladium-catalysed amido-
give [Re{C(O)CH2N-phthaloyl}(CO)5] (1), [FeCp(CH2N- carbonylation was studied using phthalimide, formaldehyde
phthaloyl)(CO)2] (2), [FeCp{C(O)CH2N-phthaloyl}(CO)2] (3), and CO as a model system which gives N-phthaloylglycine
trans-[PdBr(CH2N-phthaloyl)(PPh3)2] (4) and trans- in good yield. The proposed elementary steps in the palla-
[Pd{C(O)CH2N-phthaloyl}(X)(PPh3)2] (X = Br, Cl; 5, 6). The dium-catalysed amidocarbonylation could be verified by use
[Pd(CH2N-phthaloyl)(X)- of the possible intermediates phthaloyl-NCH2OH and
bis(phosphane)
(R2PCH2CH2PR2)]
complexes
and
[Pd{C(O)CH2N-phthaloyl}(X)-
(R2PCH2CH2PR2)] (X = Cl, Br; R = Ph, C6H11) 8−13 were ob-
phthaloyl-NCH2Br as substrates, by oxidative addition of
phthaloylmethyl bromide to Pd0, by insertion of CO into the
tained by ligand exchange from 4, 5 or 6 with the corres- palladium-carbon-bond of 4 and 8 with formation of 5 or 9,
ponding bis(phosphanes). Halide abstraction from 4, 5, 6, 10, respectively, and by use of the isolated possible interme-
11 or 12 gives the cationic complexes 14 and 15 with forma- diates 4, 5 and 14 as catalysts. Thus, all crucial steps of the
tion of a five-membered chelate ring which includes one car-
bonyl atom of the phthaloyl group. The reaction of 6 with the
palladium-catalysed amidocarbonylation with the model sys-
tem phthalimide/formaldehyde/CO have been verified for
tridentate ligand PhP(CH2CH2PPh2)2 affords the five-coord- the first time.
inate complex 16 and from [Pt(C2H4)(PPh3)2] and organic ( Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim,
halides the platinum(II
)
complexes trans-[Pt(CH2N-
Germany, 2004)
efficient process with palladium catalysts.[2] Here we report
on the synthesis of new aminomethyl and aminoacetyl me-
tal complexes with N-phthaloyl as the N-protecting
group,[3] on their role and use as catalysts in amidocarbon-
ylation reactions and on experiments which support the
mechanism of the palladium-catalysed amidocarbonylation.
Introduction
Aminomethyl and aminoacyl complexes are possible in-
termediates in the metal-catalysed amidocarbonylation, i.e.
the formation of α-amino acids from aldehydes, amide and
carbon monoxide. This three component reaction was dis-
covered by Wakamatsu et al.[1] using octacarbonyldicobalt
Several η1- and η2- (side-on) coordinated aminomethyl
as a catalyst and was more recently developed into a highly complexes are formed from methylene immonium salts
[H2CϭNR2]ϩ XϪ and organometallic compounds.[4] η1-
Aminomethyl complexes of cobaloxime result from the re-
[a]
Department Chemie der Ludwig-Maximilians-Universität
duced form of bis(dimethylglyoximato)cobalt(), formal-
München
dehyde and aniline.[5] An interesting formation of η2-(CHR-
Butenandtstr. 5Ϫ13, Haus D, 81377 München, Germany
Fax: (internat.) ϩ 49-89-2180-7464
E-mail: wbe@cup.uni-muenchen.de
Leibniz-Institut für Organische Katalyse (IfOK) an der
Universität Rostock e.V.
Buchbinderstr. 5Ϫ6, 18055 Rostock, Germany
Fax: (internat.) ϩ 49-381-466-9324
E-mail: matthias.beller@ifok.uni-rostock.de
X-ray analysis.
NH2) metal complexes is the photochemical decar-
boxylation of α-aminocarboxylatocobalt() complexes.[6]
The insertion of imines into the palladiumϪacyl bond gives
N-acyl-aminomethyl chelate complexes, a reaction which
may provide a route for the palladium-catalysed formation
of polypeptides.[7] Metalated α-amino acid derivatives of
[b]
[‡]
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DOI: 10.1002/ejic.200300617
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Complexes of PdII, PtII, FeII and ReI with N-Phthaloyl as an Amino Protecting Group
FULL PAPER
nickel,[8] palladium[7] and manganese[9] of the form LnM-
C(O)CR2-N(R)-C(O)R have also been obtained by sequen-
tial insertion of carbon monoxide and imine into metal-
carbon σ-bonds,[7Ϫ9] and recently an interesting palladium-
catalysed synthesis of Münchnones (1,3-oxazolium 5-ox-
ides, first isolated by Huisgen et al.[10]) and of α-amino acid
derivatives from imines, CO and acyl chloride building
blocks has been developed.[11] Its mechanism is similar to
that of amidocarbonylation. Rhodium complexes with N-
protected aminomethyl ligands have been prepared from
[RhCp(CH2I)(I)(PMe3)] and amides.[12] A general method
for the preparation of η1-aminomethyl and -aminoacetyl
complexes with a protected amino group is the reaction of
anionic organometallic compounds [Co(dimethylgly-
oximate)]Ϫ [13] or of metal carbonyls[14,15] with phthaloyl-
methyl halide, phthaloylglycyl chloride or with mixed anhy-
drides of N-protected α-amino acids.[16,17] The N-protected
Figure 1. Molecular structure of 2 in the crystal; selected bond
˚
aminomethyl and aminoacetyl metal carbonyls can be lengths (A) and bond angles (°): Fe(1)ϪC(1) 1.755(3), O(3)ϪC(9)
interconverted by CO insertion[14,15] or decar-
1.204(3), Fe(1)ϪC(2) 1.750(3), O(4)ϪC(16) 1.208(3), Fe(1)ϪC(8)
2.042(3), N(1)ϪC(8) 1.450(3), O(1)ϪC(1) 1.144(3), N(1)ϪC(9)
bonylation,[14,15,17] respectively, and could be useful for the
1.395(3),
O(2)ϪC(2)
1.140(3),
N(1)ϪC(16)
1.391(3);
176.0(3),
177.3(3),
119.7(2),
124.9(2),
124.6(2),
synthesis of peptides.[14]
C(2)ϪFe(1)ϪC(1)
C(1)ϪFe(1)ϪC(8)
C(2)ϪFe(1)ϪC(8)
C(16)ϪN(1)ϪC(9)
C(16)ϪN(1)ϪC(8)
93.71(14),
92.77(12),
92.07(12),
111.4(2),
124.1(2),
O(1)ϪC(1)ϪFe(1)
O(2)ϪC(2)ϪFe(1)
N(1)ϪC(8)ϪFe(1)
O(3)ϪC(9)ϪN(1)
O(4)ϪC(16)ϪN(1)
Phthalimidomethyl and -acetyl Complexes of
Iron and Rhenium Carbonyls
C(9)ϪN(1)ϪC(8) 124.2(2)
In continuation of our recent work,[14] new examples
of metal carbonyls with N-protected η1-aminomethyl and
-aminoacetyl ligands (1Ϫ3) were obtained by reactions of
the metal carbonyls [FeCp(CO)2]Ϫ and [Re(CO)5]Ϫ with
phthaloylmethyl chloride and phthaloylacetyl chloride,
respectively.
Synthesis of Phthaloylmethyl and -acetyl
Complexes of Palladium(II) and Platinum(II
)
Palladium Complexes
The oxidative addition of organic halides to zero-valent
palladium and platinum complexes is a general method for
the synthesis of σ-bonded organometallic complexes.[21]
This method was successfully applied for the synthesis of
the N-phthaloylaminomethyl- and -acetylpalladium com-
plexes 4Ϫ6, which were prepared from Pd(PPh3)4 and N-
phthaloylaminomethyl bromide, N-phthaloylaminoacetyl
Compounds 1Ϫ3 show the characteristic M(CO) and chloride or bromide, respectively. The formation of 4 takes
MeCϭO absorptions in their IR spectra (see Exp. Sect.). several days (as expected, the methyl bromide is less reactive
The 1H and 13C NMR spectra of 1Ϫ3 exhibit the ex- than the acetyl halides) and here the phosphonium salt 7 is
pected signals.
formed as a by-product. A smaller quantity of Pd(PPh)4
Crystals of 1 suitable for X-ray diffraction were obtained than stoichiometrically needed proved to be favourable for
by layering a frozen solution of 2 in CH2Cl2 with n-pentane. good yields of 4. In a separate experiment it was shown that
The molecule of 2 (Figure 1) has the classic ‘‘piano stool’’ 7 does not react with Pd(PPh3)4.
structure
as,
for
example,
in
[FeCp(COCH3)-
Complexes 4Ϫ6 decompose slowly in solution. N-
(CO)(PPh3)].[18] The Fe1ϪC8 distance [2.042(3) A] is typi- Phthaloylglycine is formed from 5 and 6 in the presence of
cal for an iron-carbon σ-bond and of similar length as in moisture. It is interesting to note that complexes 4Ϫ6 react
[Co(CH2N-phthaloyl)(CO)4] from Marko and co-workers[15] with the bis(phosphanes) R2P(CH2)2PR2 (R ϭ Ph, C6H11)
and in [FeCp(CH3)(CO){Ph2PN(CH3)CH(CH3)Ph}.[19] to give the complexes 8Ϫ13. These reactions proceed by a
In the crystal, the Cp rings of different molecules of 1 trans Ǟ cis rearrangement.
˚
are arranged in a parallel fashion. Metzler-Nolte et al.[20]
In the IR spectra of 4Ϫ13 the phthaloyl absorptions at
have reported the synthesis and structure of 1720 and 1770 cmϪ1 are characteristic. The acetyl carbonyl
[MoCp(CH2CH2-N-phthaloyl)(CO)3] which is a homologue band of 5, 6, 9, 10, 12 and 13 is observed between 1660 and
of the corresponding aminomethyl complex.[14]
1680 cmϪ1. In the 31P NMR spectra of 4Ϫ6 only one signal
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M. Beller, W. Beck et al.
FULL PAPER
is found, i.e. these complexes are formed as single trans-
isomers. The X-ray structure determination of 11 (Figure 2)
gave bonding parameters which lie in the usual range. Ab-
straction of halide ions from complexes 4Ϫ6 and 10Ϫ12
gives the cationic chelate complexes 14 and 15 in which co-
ordination of one carbonyl oxygen atom of the phthaloyl
group takes place.
Figure 2. Molecular structure of 11 in the crystal; selected bond
Interestingly, complexes 14 and 15 are formed from the
aminoacetyl complexes 5, 6, 11 and 12 by spontaneous de-
carbonylation, which is probably due to the stability of the
formed five-membered chelate ring in 14 and 15 and which
should involve alkyl migration.[22] In light of this, the reac-
tions of 5 and 6 to 14 — the trans Ǟ cis isomerisation —
can also be understood as being due to an alkyl migration.
The structures of 14 and 15 were confirmed by X-ray
diffraction (Figure 3 and 4, respectively). The chelate ring
in 14 and 15 has the same structural feature as in the pal-
ladium and platinum complexes obtained by oxidative ad-
dition of α-bromohippuric acid ester to Pd0 or Pt0 and sub-
sequent reaction with AgBF4.[23] An analogous chelate ring
˚
lengths (A) and bond angles (°): Pd(1)ϪC(27) 2.160(5),
N(1)ϪC(31) 1.402(6), Pd(1)ϪP(1) 2.3197(13) O(1)ϪC(31) 1.210(6),
Pd(1)ϪP(2) 2.2324(13) O(2)ϪC(28) 1.207(6), Pd(1)ϪBr(1)
2.5068(6),
C(28)ϪC(29)
1.500(7),
N(1)ϪC(27)
1.402(5),
C(29)ϪC(30) 1.365(7), N(1)ϪC(28) 1.379(6), C(30)ϪC(31)
1.490(7); C(27)ϪPd(1)ϪP(2) 89.03(12), C(31)ϪN(1)ϪC(27)
127.9(5), P(2)ϪPd(1)ϪP(1) 86.66(5), O(1)ϪC(31)ϪN(1) 124.8(5),
C(27)ϪPd(1)ϪBr(1) 94.32(11), N(1)ϪC(31)ϪC(30) 106.3(5),
P(1)ϪPd(1)ϪBr(1)
N(1)ϪC(27)ϪPd(1)
91.25(4),
115.3(3),
O(1)ϪC(31)ϪC(30)
O(2)ϪC(28)ϪN(1)
128.9(5),
124.9(5),
C(28)ϪN(1)ϪC(27) 121.0(5), N(1)ϪC(28)ϪC(29) 106.7(5),
C(28)ϪN(1)ϪC(31) 110.9(4), O(2)ϪC(28)ϪC(29) 128.4(6)
[23]
is also formed by insertion of imines into the metalϪacetyl C(Ph)NHCHCO2Me}(bipy)]ϩ
which is due to the
bond.[7Ϫ9] A similar chelate ring is formed from Ni0 imine strong trans-influence of the phosphane ligand.
complexes and carbon dioxide.[24] The CϪPdϪO bite
The reaction of with the tridentate ligand
6
angles in 14 and 15 (82Ϫ83°) are very similar to that of the PhP(CH2CH2PPh2)2 affords the five-coordinate, 18-electron
above-mentioned complexes.[7,8,23] The PdϪC bonds in 14 aminoacetylpalladium complex 16. The X-ray structure de-
˚
and 15 (2.07Ϫ2.08 A) are longer than that in [Pd{Oϭ termination (Figure 5) shows the molecule of 16 as a dis-
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Complexes of PdII, PtII, FeII and ReI with N-Phthaloyl as an Amino Protecting Group
FULL PAPER
a series of such complexes with chelate ligands has been
isolated and structurally characterised.[25Ϫ27]
torted trigonal bipyramid with P(1) and P(3) in the axial
positions. The P(1), P(3) and Cl(1) atoms lie in a plane (sum
of angles 360°). The unusually long PdϪCl(1) bond (2.69
˚
A) is remarkable. In the crystal of 16 there are large voids
Platinum Complexes
which are occupied by solvent molecules (dichloromethane
and n-pentane).
Similar five-coordinate palladium and platinum com-
plexes are intermediates in many catalytic reactions,[25] and
The platinum complexes 17 and 18 were obtained by oxi-
dative addition of N-phthaloylglycyl chloride or N-
phthaloylphenylalanyl chloride to [Pt(C2H4)(PPh3)2]. The
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M. Beller, W. Beck et al.
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bis(diphenylphosphanyl)ethane complex 19 was synthesised
from 18 by ligand exchange.
Figure 3. Molecular structure of 14 in the crystal; selected bond
˚
lengths (A) and bond angles (°): Pd(1)ϪC(1) 2.066(4), N(1)ϪC(1)
1.454(6), O(2)ϪC(9) 1.194(6), Pd(1)ϪP(1) 2.2194(12), N(1)ϪC(2)
1.341(6), C(2)ϪC(3) 1.480(6), Pd(1)ϪP(2) 2.3882(12), N(1)ϪC(9)
1.429(6), C(8)ϪC(9) 1.474(8), Pd(1)ϪO(1) 2.125(3), O(1)ϪC(2)
1.232(5); C(1)ϪPd(1)ϪO(1) 83.05(15), C(2)ϪO(1)ϪPd(1) 108.0(3),
N(1)ϪC(2)ϪC(3) 108.9(4), O(1)ϪPd(1)ϪP(2) 87.12(9), C(2)Ϫ
N(1)ϪC(9) 111.0(4), O(1)ϪC(2)ϪC(3) 127.7(4), C(1)ϪPd(1)ϪP(1)
91.08(13), C(9)ϪN(1)ϪC(1) 127.7(4), O(2)ϪC(9)ϪC(8) 130.6(5),
P(1)ϪPd(1)ϪP(2) 98.50(4), C(2)ϪN(1)ϪC(1) 121.0(3), N(1)Ϫ
C(9)ϪC(8) 105.0(4), N(1)ϪC(1)ϪPd(1) 103.5(3), O(1)ϪC(2)ϪN(1)
123.4(4), O(2)ϪC(9)ϪN(1) 124.5(5)
Experiments on the Mechanism of the
Palladium-Catalyzed Amidocarbonylation
The proposed mechanism of the palladium-catalysed
amidocarbonylation with aldehydes, amides and CO is
shown in Scheme 1.[3]
Figure 4. Molecular structure of 15 in the crystal; selected bond
˚
lengths (A) and bond angles (°): Pd(2)ϪC(11) 2.083(4),
In order to study the elementary steps of the mechanism
the palladium-catalysed formation of phthaloylglycine from
phthalimide, formaldehyde and CO was chosen as a model
system. In the absence of CO and Pd2ϩ, phthalimide reacts
with formaldehyde to give N-(hydroxymethyl)phthal-
imide.[13] The chosen reactants seemed to be favourable be-
cause phthalimide cannot form an oxazolone ring as side-
product and the aldehyde does not carry β-hydrogen atoms.
Hence, β-hydride elimination is not possible and a satisfying
yield of 55% of the glycine derivative was achieved at 120
N(2)ϪC(11) 1.464(5), O(6)ϪC(19) 1.202(5), Pd(2)ϪP(1) 2.3193(11)
N(2)ϪC(12) 1.364(5), C(12)ϪC(13) 1.473(5), Pd(2)ϪP(2)
2.2203(10) N(2)ϪC(19) 1.403(5), C(18)ϪC(19) 1.488(6),
Pd(2)ϪO(2) 2.148(3), O(2)ϪC(12) 1.238(5); C(11)ϪPd(2)ϪO(2)
82.71(12), C(12)ϪO(2)ϪPd(2) 109.4(3), N(2)ϪC(12)ϪC(13)
107.6(4), O(2)ϪPd(2)ϪP(1) 98.49(7), C(12)ϪN(2)ϪC(19) 111.0(3),
O(2)ϪC(12)ϪC(13) 129.7(4), C(11)ϪPd(2)ϪP(2) 92.66(11),
C(19)ϪN(2)ϪC(11) 127.7(3), O(6)ϪC(19)ϪC(18) 129.7(4),
P(1)ϪPd(2)ϪP(2)
86.12(4),
C(12)ϪN(2)ϪC(11)
121.1(3),
N(2)ϪC(19)ϪC(18) 105.9(4), N(2)ϪC(11)ϪPd(2) 104.2(2),
O(2)ϪC(12)ϪN(2) 122.6(4), O(6)ϪC(19)ϪN(2) 124.4(4)
°C and 60 bar CO using 0.25 mol % PdBr2 and 0.5 mol % dehyde (Table 1). In many experiments[2] the temperature of
PPh3 as catalyst in the presence of 35 mol % LiBr and 1 120 °C proved to be favourable. Experiments 3 and 4 in
mol % H2SO4. The yield strongly decreases at lower tem- Table 2 demonstrate the need for halide and acid as cocata-
perature (Table 1).
The following results confirm the previously proposed 2) Oxidative addition of the organic halide to Pd0 was veri-
mechanism:[2]
fied by the isolation of complex 4 from the reaction of
lysts.
1) With (hydroxymethyl)phthalimide or (bromometh- (bromomethyl)phthalimide and Pd(PPh3)4.
yl)phthalimide as substrate the same yield of phthaloylgly- 3) The insertion of carbon monoxide into the
cine (55%) is obtained as with phthalimide and paraformal- aminoalkylϪpalladium bond (which may occur via alkyl
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Complexes of PdII, PtII, FeII and ReI with N-Phthaloyl as an Amino Protecting Group
FULL PAPER
Table 1. Palladium-catalysed amidocarbonylation with the model
system phthalimide/formaldehyde
Exp.
Temperature (°C)
Yield (%)[a]
1
2
3
80
100
120
Ϫ
20
55
Figure 5. Molecular structure of 16 in the crystal; selected bond
˚
lengths (A) and bond angles (°): Pd(1)ϪC(1) 2.035(2), Pd(1)ϪCl(1)
2.6855(6), C(3)ϪN(1) 1.399(3), Pd(1)ϪP(1) 2.3133(6), C(1)ϪC(2)
1.540(3), N(1)ϪC(10) 1.379(3), Pd(1)ϪP(2) 2.3381(6), O(1)ϪC(1)
1.195(3), O(2)ϪC(10) 1.214(3), Pd(1)ϪP(3) 2.3297(6), C(2)ϪN(1)
1.454(3), O(3)ϪC(3) 1.195(3); P(1)ϪPd(1)ϪP(2) 85.20(2),
C(1)ϪPd(1)ϪP(3) 91.67(6), C(2)ϪC(1)ϪPd(1) 115.07(15) P(1)Ϫ
Pd(1)ϪP(3) 137.67(2) P(1)ϪPd(1)ϪCl(1) 114.10(2) N(1)ϪC(2)
ϪC(1) 112.64(19) P(3)ϪPd(1)ϪP(2) 85.30(2), P(2)ϪPd(1)ϪCl(1)
97.626(19) C(10)ϪN(1)ϪC(2) 124.8(2), C(1)ϪPd(1)ϪP(1) 89.82(7),
P(3)ϪPd(1)ϪCl(1) 108.02 (2) C(10)ϪN(1)ϪC(3) 111.9(2),
[a]
Isolated yield.
migration[22]) has been realized with the alkyl complexes 4
and 8 in CD2Cl2 solutions. The reaction was followed by
31P NMR spectroscopy in a high pressure NMR tube. With
4 at 60 °C and 50 bar CO after 180 min the signal (δ ϭ
19.7 ppm) of the acetyl complex 6 was detected (besides
C(1)ϪPd(1)ϪCl(1)
C(3)ϪN(1)ϪC(2)
93.61(7),
122-.8(2)
O(1)ϪC(1)ϪPd(1)
C(1)ϪPd(1)ϪP(2)
125.99(17)
168.76(7)
O(1)ϪC(1)ϪC(2) 118.9(2)
Scheme 1
Eur. J. Inorg. Chem. 2004, 1330Ϫ1340
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1335

M. Beller, W. Beck et al.
FULL PAPER
alanyl chloride[31] were prepared according to the literature. The
other starting materials were used as purchased.
that of 7 at δ ϭ 21.9 ppm). Similarly, with 8 at 50 bar CO
and 130 °C after 1 h two 31P NMR doublets were observed
(with low intensity) which correspond to 9. Obviously the
CO insertion is more difficult with 8, which has a bis(phos-
phane) chelate ligand.
Pentacarbonyl(N-phthaloylaminoacetyl)rhenium(I) (1): Dirhenium-
decacarbonyl (700 mg, 1.1 mmol) was added to a mixture of 20.1 g
of Na/Hg (6.63 mmol Na) and 25 mL of THF while stirring and
cooling to Ϫ78 °C. After 1 h, the mixture was allowed to warm up
The reverse decarbonylation reaction has been observed in
CH2Cl2 solution of 12 where, after 1Ϫ2 days at 20 °C, the to room temperature and was stirred for 2 h. The dark-red solution
31P NMR signals of 11 appeared. Also, the spontaneous
was removed with a syringe and added slowly to a solution of
380 mg of N-phthaloylglycyl chloride in 15 mL of THF at Ϫ78 °C.
decarbonylation of 5, 6, 11 and 12 when treated with Agϩ
After 2 h of stirring at room temperature, the suspension was fil-
should be mentioned here.
tered and the filtrate was concentrated in vacuo. The resulting resi-
4) The final step of the catalytic cycle — the hydrolysis of
the acetylpalladium complex and formation of palladium(0)
due was washed several times with water, dried in vacuo and crys-
tallised from CH2Cl2/n-pentane to give 735 mg of the colourless
and phthaloylglycine — is supported by the observation
product (84% yield). 1H NMR (270 MHz, 25 °C, CDCl3): δ ϭ
that N-phthaloylglycine and palladium black are formed
from solutions of 5 and 6 in CH2Cl2 in contact with air. It
is remarkable that in entry 6 (Table 2) without addition of
7.85Ϫ7.60 (m, 4 H, C6H4), 4.46 (s, 2 H, CH2) ppm. 13C{1H} NMR
(100.5 MHz, 25 °C, CDCl3):
δ ϭ 246.3 [ReC(O)R], 181.9
[Re(CO)5], 180.7 [Re(CO)5], 167.9 (CON), 134.0, 132.3, 123.4
water phthaloylglycine was not formed from phthaloylme- (C6H4), 69.4 (CH2) ppm. IR (Nujol): ν˜ ϭ 2141 m, 2066 s, 2039,
2012 s, 1774 w, 1713 s, 1619 s cmϪ1. C15H6NO8Re (514.4): calcd.
C 35.02, H 1.18, N 2.72; found C 34.57, H 1.26, N 2.69.
thyl bromide. Addition of methanol (entry 7, Table 2) gave
N-phthaloylglycine (20%) and N-(methoxy)methylphthal-
imide (65%) as products.
Dicarbonyl(cyclopentadienyl)(N-phthaloylaminomethyl)iron(II
)
(2):
Na/Hg (10.24 g, 3.3 mmol Na) was treated with a solution of
bis(dicarbonylcyclopentadienyliron) (400 mg, 1.1 mmol) in 20 mL
of THF at Ϫ78 °C. While stirring, the mixture was allowed to
warm up to room temperature. After 3 h, the solution was removed
with a syringe and added slowly to a solution of bromometh-
ylphthalimide (456 mg, 1.9 mmol) in 15 mL of THF at Ϫ78 °C.
The resulting dark red solution was stirred for 2 h at Ϫ78 °C and
3 h at room temperature. The colourless precipitate was separated
by centrifugation. The dark red solution was concentrated in vacuo
and the residue was crystallised from a CH2Cl2/n-pentane mixture.
One of the resulting yellow crystals was selected for X-ray analysis.
The rest of the product was dried in vacuo. Yield: 423 mg (66%).
1H NMR (270 MHz, 25 °C, CDCl3): δ ϭ 7.80Ϫ7.20 (m, 4 H,
Table 2. Use of intermediates in the model system phthalimide/
formaldehyde
Exp. R1
Addition
[equiv.]
H2SO4 LiBr
Product yield
[equiv.] [equiv.] [%][a] R2
1
2
3
4
5
6
7
H
CH2O [1.0] 0.001 0.35
ϪCH2CO2H 55 C6H4), 4.94 (s, 5 H, C5H5), 3.99 (s, 2 H, CH2) ppm. 13C{1H} NMR
ϪCH2CO2H 57
ϪCH2CO2H 10
Ϫ
ϪCH2CO2H 48
Ϫ
ϪCH2CO2Me 20
ϪCH2OH
ϪCH2OH
ϪCH2OH
ϪCH2Br
ϪCH2Br
ϪCH2Br
Ϫ
Ϫ
Ϫ
0.01
Ϫ
0.01
0.01
0.01
0.35
0.35
Ϫ
Ϫ
Ϫ
(100.5 MHz, 25 °C, CDCl3): δ ϭ 215.8 [Fe(CO)2], 168.7 (CON),
133.7, 133.4, 122.7, (C6H4), 85.4 (C5H5), 11.2 (FeCH2) ppm. IR
(Nujol): ν˜ ϭ 2002 s, 1960 s, 1770 m, 1708 s cmϪ1. C16H11FeNO4
(337.1): calcd. C 57.01, H 3.29, N 4.15; found C 56.83, H 3.24,
N 4.14.
H2O [1.0]
Ϫ
MeOH [1.0] 0.01
Ϫ
ϩ ϪCH2OMe 65
Ϫ
Ϫ
Dicarbonyl(cyclopentadienyl)(N-phthaloylaminoacetyl)iron(II
)
(3):
8
9
ϪCH2OMe Ϫ
ϪCH2OMe Ϫ
0.01
0.01
Ϫ
0.35
Na/Hg (3.66 g, 1.1 mmol Na) was treated with a solution of
bis(dicarbonylcyclopentadienyliron) (140 mg, 0.4 mmol) in 15 mL
of THF at Ϫ78 °C. While stirring, the mixture was allowed to
warm up to room temperature. After 3 h, the solution was removed
with a syringe and added slowly to a solution of N-phthaloylami-
noacetyl chloride (180 mg, 0.8 mmol) in 15 mL of THF at Ϫ78 °C.
[a]
Isolated yield.
5) Finally, the complexes 4, 5 and 14, which are possible
intermediates in the amidocarbonylation, were used as cata-
lysts for the reaction of phthalimide with paraformal- The resulting dark solution was stirred for 1 h at Ϫ78 °C and 1 h
at room temperature. The colourless precipitate was separated by
centrifugation. The dark red solution was concentrated in vacuo
and the residue was crystallised from a CH2Cl2/n-pentane mixture
to afford 222 mg of yellow crystals (76% yield). 1H NMR
(270 MHz, 25 °C, CDCl3): δ ϭ 7.80Ϫ7.50 (m, 4 H, C6H4), 4.94 (s,
5 H, C5H5), 4.56 (s, 2 H, CH2) ppm. IR (Nujol): ν˜ ϭ 2016 s, 1963
s, 1773 w, 1708 s, 1665 s cmϪ1. C17H11FeNO5 (365.1): calcd. C
55.92, H 3.04, N 3.84; found C 55.52, H 3.10, N 3.96.
dehyde. Under standard conditions (0.25 mol % complex,
120 °C, 60 bar CO, in NMP, 12 h) N-phthaloylglycine was
obtained in yields of 48, 45 or 51% which corresponds to
the activity of the normal catalyst PdBr2·2PPh3.
In summary, all critical steps of the palladium-catalysed
amidocarbonylation (Scheme 1) have been fully established
for the model system phthalimide/formaldehyde/CO.
trans-Bromo(N-phthaloylaminomethyl)bis(triphenylphosphane)-
palladium(II) (4): (Bromomethyl)phthalimide (200 mg, 0.83 mmol)
was dissolved in 30 mL of benzene and Pd(PPh3)4 (960 mg,
0.83 mmol) was added at room temperature. After stirring for 2
Experimental Section
The complexes Pd(PPh3)4,[28] [Pt(C2H4)(PPh3)2][29] N-phthaloylgly-
cyl chloride, N-phthaloylglycyl bromide[30] and N-phthaloylphenyl- days the resulting precipitate was separated by centrifugation, and
1336
 2004 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
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Eur. J. Inorg. Chem. 2004, 1330Ϫ1340

Complexes of PdII, PtII, FeII and ReI with N-Phthaloyl as an Amino Protecting Group
FULL PAPER
3
washed with a small amount of benzene and pentane. The by-
product 7 was extracted from the residue with methanol. The re-
maining solid was dissolved in CH2Cl2 and precipitated with pen-
tane. The yellow product was washed with a small amount of ben-
zene and dried in vacuo. Yield: 178 mg (73%). 1H NMR (400 MHz,
(m, 24 H, C6H4, PPh2), 3.36 (4t, JP,H ϭ 6.8 Hz, 2 H, CH2), 2.41
(m, 2 H, P-CH2), 2.06 (m, 2 H, P-CH2) ppm. 13C{1H} NMR
(100.5 MHz, 25 °C, CD2Cl2): δ ϭ 167.0 (CON), 135.1, 134.0, 131.6,
131.2, 130.6, 128.0, 122.8 (C6H4, PPh2), 49.5 (CH2); 21.1 (P-CH2),
19.6 (P-CH2) ppm. 31P{1H} NMR (109.4 MHz, 25 °C, CD2Cl2):
2
2
25 °C, CD2Cl2): δ ϭ 7.84Ϫ7.30 (m, 34 H, C6H4, PPh3), 2.71 (br., δ ϭ 58.80 (d, JP,P ϭ 32 Hz, 1 P), 36.81 (d, JP,P ϭ 32 Hz, 1 P)
2 H, CH2) ppm. 13C{1H} NMR (100.5 MHz, 25 °C, CD2Cl2): δ ϭ ppm. IR (KBr): ν˜ ϭ 3051 w, 2937 w, 1773 w, 1695 s, 1442 s cmϪ1
.
169.2 (CON), 135.0, 133.1, 131.3, 130.2, 128.3, 128.0, 121.9 (C6H4, C35H30BrNO2P2Pd (744.9): calcd. C 56.44, H 4.06, N 1.88; found
PPh3), 54.0 (CH2) ppm. 31P{1H} NMR (109.4 MHz, 25 °C, C 56.80, H 4.15, N 1.86.
CD2Cl2): δ ϭ 26.8 (s) ppm. IR (KBr): ν˜ ϭ 3057 w, 1771 w, 1699 s,
cis-Bromo[1,2-bis(diphenylphosphanyl)ethane](N-phthaloyl-
aminoacetyl)palladium(II) (9): trans-Bromo(N-phthaloylaminoace-
tyl)bis(triphenylphosphane)palladium() (5; 180 mg, 0.23 mmol)
and bis(diphenylphosphanyl)ethane (108 mg, 0.27 mmol) were
stirred in 15 mL of benzene for 2 h at room temperature. The pre-
1436 s cmϪ1. C45H36BrNO2P2Pd·0.25CH2Cl2 (892.3): calcd. C
60.94, H 4.12, N 1.57; found C 60.91, H 3.92, N 1.47.
trans-Bromo(N-phthaloylaminoacetyl)bis(triphenylphosphane)-
palladium(II) (5): N-Phthaloylglycyl bromide (220 mg, 0.77 mmol)
was dissolved in 30 mL of benzene and Pd(PPh3)4 (1202 mg, cipitate was separated by centrifugation, washed with benzene and
0.77 mmol) was added at room temperature. After stirring for 1 h
the resulting precipitate was separated by centrifugation, washed
with benzene and diethyl ether and dried in vacuo to give 592 mg
of the yellow product (76% yield). 1H NMR (270 MHz, 25 °C,
diethyl ether and dried in vacuo to give 158 mg of the pale yellow
product (89% yield). 1H NMR (270 MHz, 25 °C, CD2Cl2): δ ϭ
7.90Ϫ7.10 (m, 24 H, C6H4, PPh2), 4.61 (s, CH2), 2.42 (m, 2 H,
CH2CH2), 2.19 (m,
2
H, CH2CH2) ppm. 31P{1H} NMR
2
CD2Cl2): δ ϭ 7.88Ϫ7.25 (m, 34 H, C6H4, PPh3), 4.03 (s, 2 H, CH2) (109.5 MHz, 25 °C, CD2Cl2): δ ϭ 42.47 (d, JP,P ϭ 43 Hz, 1 P),
ppm. 13C{1H} NMR (100.5 MHz, 25 °C, CD2Cl2): δ ϭ 228.8 27.58 (d, JP,P ϭ 43 Hz, 1 P). IR (Nujol): ν˜ ϭ 1771, 1715, 1672,
2
[PdC(O)R], 166.8 (CON), 135.1, 134.0, 131.8, 130.5, 128.3, 123.2
1435 cmϪ1. C36H30BrNO3P2Pd (772.9): calcd. C 55.94, H 3.91, N
(C6H4, PPh3), 39.8 (CH2) ppm. 31P{1H} NMR (109.4 MHz, 25 °C, 1.88, Br, 10.34; found C 55.82, H 3.52, N 1.78, Br 10.18.
CD2Cl2): δ ϭ 19.8 (s) ppm. IR (KBr): ν˜ ϭ 3054 w, 1772 w, 1719 s,
cis-Chloro[1,2-diphenylphosphanyl)ethane](N-phthaloyl-
aminoacetyl)palladium(II) (10): Complex 6 (163 mg, 0.19 mmol)
and 1,2-bis(diphenylphosphanyl)ethane (80 mg, 0.20 mmol) in
25 mL of benzene were stirred at room temperature. After 30 min
a clear solution was obtained and after 2 h a yellow precipitate
1684 s, 1436 s cmϪ1. C46H36BrNO3P2Pd (899.1): calcd. C 61.45, H
4.04, N 1.56; found C 61.57, H 4.15, N 1.56.
trans-Chloro(N-phthaloylaminoacetyl)bis(triphenylphosphane)-
palladium(II) (6): N-Phthaloylglycyl chloride (132 mg, 0.57 mmol)
was dissolved in 20 mL of benzene and Pd(PPh3)4 (890 mg, appeared which was centrifuged off and washed several times with
0.57 mmol) was added at room temperature. After stirring for 1 h benzene and n-pentane. Pale yellow powder. Yield: 109 mg (79%).
the resulting precipitate was separated by centrifugation, washed
with benzene and diethyl ether and dried in vacuo. The colourless
product was obtained in 81% yield (487 mg). H NMR (270 MHz,
1H NMR (400 MHz, 25 °C, Cd2Cl2): δ ϭ 7.87Ϫ7.20 (m, 24 H,
PPh2, C6H4), 4.64 (s, 2 H, CH2), 2.47 (m, 2 H, CH2CH2), 2.18 (m,
2 H, CH2CH2) ppm. 31P{H} NMR (109.4 MHz, 25 °C, CD2Cl2):
δ ϭ 44.88 (d, 2JP,P ϭ 41 Hz, 1 P), 28.5 (d, 2JP,P ϭ 41 Hz, 1 P) ppm.
1
25 °C, CD2Cl2): δ ϭ 7.72Ϫ7.36 (m, 34 H, C6H4, PPh3), 3.96 (s, 2
H, CH2) ppm. 13C{1H} NMR (100.5 MHz, 25 °C, CD2Cl2): δ ϭ IR (Nujol): ν˜ ϭ 1770, 1716, 1670, 1437 cmϪ1. C36H30ClNO3P2Pd
210.4 [PdC(O)R], 166.6 (CON), 134.8, 133.8, 131.7, 131.0, 130.4,
128.2, 123.0 (C6H4, PPh3), 21.9 (CH2) ppm. 31P{1H} NMR
(109.4 MHz, 25 °C, CD2Cl2): δ ϭ 20.30 (s) ppm. IR (KBr): ν˜ ϭ
1770 w, 1716 s, 1660 s, 1437 s cmϪ1. C46H36ClNO3P2Pd (854.6):
calcd. C 64.65, H 4.25, N 1.64; found C 64.69, H 4.30, N 1.65.
(728.5): calcd. C 59.36, H 4.15, N 1.92; found C 59.53, H 4.50,
N 2.01.
cis-Bromo[1,2-bis(dicyclohexylphosphanyl)ethane](N-phthaloyl-
aminomethyl)palladium(II
methyl)bis(triphenylphosphane)palladium()
0.19 mmol) and bis(dicyclohexylphosphanyl)ethane (81 mg,
)
(11): trans-Bromo(N-phthaloylamino-
(4; 167 mg,
N-Phthaloylaminomethyltriphenylphosphonium Bromide (7): This
compound was obtained as by-product with 4. Compound 7 was 0.19 mmol) were stirred in 25 mL of benzene for 2 h at room tem-
also prepared from bromomethylphthalimide and triphenylphos- perature. The precipitate was separated by centrifugation, washed
phane in benzene. 1H NMR (400 MHz, 25 °C, CD2Cl2): δ ϭ with benzene and diethyl ether and crystallised from CH2Cl2/pen-
7.72Ϫ7.36 (m, 34 H, C6H4, PPh3), 3.96 (s, 2 H, CH2) ppm. 13C{H}
tane. One of the resulting yellow crystals was selected for X-ray
NMR (100.5 MHz, 25 °C, CD2Cl2): δ ϭ 166.5 (CON), 135.8 (d, analysis. The rest were dried in vacuo to afford 102 mg of product
1
4JP,C ϭ 3 Hz, PPh3), 135.1 (C6H4), 134.5 (d, 2JP,C ϭ 10.0 Hz, PPh3), (70% yield). H NMR (400 MHz, 25 °C, CD2Cl2): δ ϭ 7.70Ϫ7.40
3
131.0 (C6H4), 130.4 (d, 3JP,C ϭ 12.5 Hz, PPh3), 123.9 (C6H4), 116.3
(m, 4 H, C6H4), 3.46 (pseudo-t, JP,H ϭ 6.1 Hz, 2 H), 2.40Ϫ1.00
(d, JP,C ϭ 84.6 Hz, PPh3), 35.9 (d, JP,C ϭ 57.3 Hz, PCH2) ppm. (m, 48 H, C6H11, CH2CH2) ppm. 13C{1H} NMR (100.5 MHz, 25
1
1
31P{1H} NMR (109.4 MHz, 25 °C, CD2Cl2): δ ϭ 20.3 (s) ppm. °C, CD2Cl2): δ ϭ 168.7 (CON), 133.7, 132.5, 128.3, 121.8 (C6H4),
1
2
C27H21BrNO2P (502.3): calcd. C 63.72, H 4.40, N 2.79, Br 15.89;
found C 64.56, H 4.21, N 2.67, Br 15.91. The found analyses are
from the by-product of 4.
ca. 53.7 (CH2), 35.8Ϫ26.0 (C6H11), 25.3 (dd, JP,C ϭ 27.6, JP,C ϭ
21.5 Hz, CH2), 20.2 (dd, 1JP,C ϭ 19.8, JP,C ϭ 19.4 Hz, CH2) ppm.
2
31P{1H} NMR (109.4 MHz, 25 °C, CD2Cl2): δ ϭ 74.02 (d, JP,P
ϭ
2
2
18 Hz, 1 P), 66.34 (d, JP,P ϭ 18 Hz, 1 P) ppm. IR (Nujol): ν˜ ϭ
1770 w, 1701 s, 1417 s. C35H54BrNO2P2Pd (769.1): calcd. C 54.66,
H 7.08, N 1.82; found C 55.00, H 6.69, N 1.81.
cis-Bromo[1,2-bis(diphenylphosphanyl)ethane](N-phthaloyl-
aminomethyl)palladium(II
aminomethyl)bis(triphenylphosphane)palladium() (4; 500 mg,
0.57 mmol) and bis(diphenylphosphanyl)ethane (230 mg,
)
(8):
trans-Bromo(N-phthaloyl-
cis-Bromo[1,2-bis(dicyclohexylphosphanyl)ethane](N-phthaloyl-
aminoacetyl)palladium(II) (12): trans-Bromo(N-phthaloylaminoace-
tyl)bis(triphenylphosphane)palladium() (5; 152 mg, 0.17 mmol)
and bis(dicyclohexylphosphanyl)ethane (72 mg, 0.17 mmol) were
0.57 mmol) were stirred in 20 mL of benzene for 2 h. The precipi-
tate was separated by centrifugation, washed with benzene and di-
ethyl ether and dried in vacuo to give 318 mg of the yellow product
1
(75% yield). H NMR (400 MHz, 25 °C, CD2Cl2): δ ϭ 7.85Ϫ7.25 stirred in 20 mL of benzene for 2 h at room temperature. The pre-
Eur. J. Inorg. Chem. 2004, 1330Ϫ1340
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 2004 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
1337

M. Beller, W. Beck et al.
FULL PAPER
cipitate was separated by centrifugation, washed with benzene and
diethyl ether and dried in vacuo to give 103 mg of the yellow prod-
ethyl)phenylphosphane (120 mg, 0.22 mmol) was added to a solu-
tion of 6 (130 mg, 0.15 mmol) in 25 mL of benzene and stirred for
uct (88% yield). 1H NMR (270 MHz, 25 °C, CD2Cl2): δ ϭ 3 h. The yellow precipitate was centrifuged off, washed several
7.83Ϫ7.65 (m, 4 H, C6H4), 4.99 (s, 2 H, CH2), 2.20Ϫ1.20 (m, 48
times with benzene and n-pentane and dried in vacuo. The pale
H, C6H11, CH2CH2) ppm. 13C NMR (100.5 MHz, 25 °C, CD2Cl2): yellow powder was dissolved in dichloromethane. The solution was
δ ϭ 206.4 [PdC(O)R], 167.7 (CON), 133.7, 132.5, 123.0 (C6H4), filtered through celite and layered with n-pentane. After some days
1
2
35.0Ϫ26.0 (C6H11), 30.6 (CH2), 24.5 (dd, JP,C ϭ 21.5 Hz, JP,C
ϭ
pale yellow crystals were formed which were suitable for X-ray dif-
27.6 Hz, CH2CH2), 19.4 (dd, JP,C ϭ 10.4 Hz, JP,C ϭ 14.8 Hz, fraction. Yield 66%. 1H NMR (270 MHz, 25 °C, CD2Cl2): δ ϭ
CH2CH2) ppm. 31P{1H} NMR (109.4 MHz, 25 °C, CD2Cl2): δ ϭ
8.00Ϫ7.00 (m, 29 H, C6H4, PPh2, PPh), 4.34 (s, 2 H, CH2),
1
2
67.05 (d, JP,P ϭ 34 Hz, 1 P), 54.68 (d, JP,P ϭ 34 Hz, 1 P) ppm. 3.50Ϫ2.10 (m, 8 H, PCH2CH2PCH2CH2P) ppm. 31P{1H} NMR
2
3
C36H54BrNO3P2Pd (797.1): calcd. C 54.25, H 6.83, N 1.76, Br
10.02; found C 53.94, H 6.92, N 1.66, Br 9.87.
(109.4 MHz, 25 °C, CD2C2): δ ϭ 80.0 (t, 2JP,P ϭ 36.8 Hz, 1 P, PPh),
2
35.5 (d, JP,P ϭ 36.7 Hz, 2 P, -PPh2) ppm. IR (Nujol): ν˜ ϭ 1769 w,
1714 s, 1699 w, 1663 m cmϪ1. C44H39ClNO3P3Pd (864.6): calcd. C
61.13, H 4.55, N 1.62; found C 61.31, H 5.29, N 1.14.
cis-Chloro[1,2-bis(diphenylphosphanyl)ethane](N-phthaloylamino-
acetyl)palladium(II) (13): Compound 6 (180 mg, 0.21 mmol) and
bis(diphenylphosphanyl)ethane (90 mg, 0.21 mmol) were stirred in
30 mL of benzene. After 1 h a clear solution was obtained from
which, after 2Ϫ3 h, a yellow precipitate appeared. The solid was
centrifuged off and washed several times with benzene and n-pen-
trans-Chloro(N-phthaloylaminoacetyl)bis(triphenylphosphane)-
platinum(II) (17): (η2-Ethene)bis(triphenylphosphane)platinum(0)
(126 mg, 0.17 mmol) was dissolved in 20 mL of benzene and N-
phthaloylglycyl chloride (67 mg, 0.30 mmol) was added to the yel-
low solution at room temperature. After stirring for 1 h the re-
sulting precipitate was separated by centrifugation, washed with
benzene and diethyl ether and dried in vacuo to give 175 mg of
colourless product (93% yield). 1H NMR (270 MHz, 25 °C,
CDCl3): δ ϭ 7.50Ϫ6.80 (m, 34 H, C6H4, PPh3), 3.30 (s, 2 H, CH2)
ppm. 13C{1H} NMR (100.5 MHz, 25 °C, CD2Cl2): δ ϭ 210.2
[PtC(O)R], 166.9 (CON), 135.0, 133.4, 132.1, 130.5, 130.1, 128.2,
1
tane, and dried in vacuo. Yellow powder. Yield: 136 mg (86%). H
NMR (270 MHz, 25 °C, CD2Cl2): δ ϭ 7.85Ϫ7.65 (m, 4 H, C6H4),
5.04 (s, 2 H, CH2), 2.25Ϫ1.20 (m, 48 H, C6H11, CH2CH2) ppm.
2
31P{H} NMR (109.4 MHz, 25 °C, CD2Cl2): δ ϭ 69.43 (d, JP,P
ϭ
3
31 Hz, 1 P), 54.68 (d; JP,P ϭ 31 Hz, 1 P). IR (Nujol): ν˜ ϭ 1767
w, 1714 s, 1677 m, 1436 m cmϪ1. C36H54ClNO3P2Pd·0.25CH2Cl2
(773.9): calcd. C 56.26, H 7.10, N 1.81; found C 56.63, H 7.04,
N 1.43.
122.9 (C6H4, PPh3), 59.0 (CH2) ppm. 31P{1H} NMR (109.4 MHz,
1
25 °C, CD2Cl2): δ ϭ 35.8 (sat), 20.6 (s), 5.3 (sat) ppm; JP,Pt
ϭ
3330 Hz. IR (KBr): ν˜ ϭ 1772 w, 1717 s, 1658 s, 1435 s cmϪ1
.
Complex 14: A solution of 6 (50 mg, 0.06 mmol) in 15 mL of di-
chloromethane was treated with AgBF4 (12 mg, 0.06 mmol) at Ϫ78
°C. The mixture was allowed to warm up to room temperature and
was stirred for 4 h. The colourless solid was separated by centrifug-
ation and the yellow solution was concentrated and layered with n-
pentane. Yellow crystals suitable for X-ray diffraction were ob-
tained. Yield: 38 mg (72%). Complex 14 was also obtained from 4
or 5 using the same procedure. 1H NMR (270 MHz, 25 °C,
CD2Cl2): δ ϭ 7.80Ϫ7.15 (m, 40 H, C6H4, PPh3), 3.22 (pseudo-t,
3JP,H ϭ 2 Hz, 2 H, CH2) ppm. 31P{H} NMR (109.4 MHz,
25 °C, CD2Cl2): δ ϭ 36.42 (br., 1 P), 18.77 (br., 1 P) ppm. IR
C46H36ClNO3P2Pt (959.7): calcd. C 58.60, H 3.85, N 1.49; found
C 58.60, H 3.87, N 1.41.
trans-Chloro(N-phthaloylphenylalanyl)bis(triphenylphosphane)-
platinum(II) (18): (η2-Ethene)bis(triphenylphosphane)platinum(0)
(340 mg, 0.5 mmol) was dissolved in 25 mL of benzene and N-
phthaloylphenylalanyl chloride (67 mg, 0.30 mmol) was added to
the yellow solution at room temperature. After stirring for 12 h the
resulting precipitate was separated by centrifugation, washed with
benzene and diethyl ether and dried in vacuo to afford 377 mg of
1
ϭ 1777 w, 1711 m, 1635 s, 1439 s .
cmϪ1
an almost colourless product (73% yield). H NMR (270 MHz, 25
(Nujol): ν˜
°C, CDCl3): δ ϭ 7.90Ϫ7.05 (m, 34 H, C6H4, PPh3), 6.87 (m, 3 H,
C45H36BF4NO3Pd·0.25CH2Cl2 (899.2): calcd. C 60.44, H 4.06, N
1.56; found C 60.44, H 4.23, N 1.53.
3
2
p-C6H4), 6.50 (m, 2 H, C6H4), 3.84 (dd, JH,H ϭ 4.1 Hz, JH,H
ϭ
2
3
12.3 Hz, 1 H, CH), 3.02 (dd, JH,H ϭ 14.1 Hz, JH,H ϭ 4.1 Hz, 1
H, CH2), 2.74 (dd, 2JH,H ϭ 14.3, 3JH,H ϭ 12.1 Hz, 1 H, CH2) ppm.
13C{1H} NMR (100.5 MHz, 25 °C, CDCl3): δ ϭ 213.6 [PtC(O)R],
171.4 (CON), 138.0, 135.3, 133.7, 131.6, 130.6, 128.6, 128.0, 126.0,
123.4, 123.1 (C6H4, Ph, PPh3), 60.5 (CH), 41.1 (CH2) ppm.
31P{1H} NMR (109.4 MHz, 25 °C, CDCl3): δ ϭ 37.4 (sat), 21.8
Complex 15: A solution of 12 (127 mg, 0.18 mmol) in 20 mL of
CH2Cl2 was cooled to Ϫ78 °C, treated with AgBF4 (35 mg,
0.18 mmol) and stirred for 1 h. Then, the mixture was warmed up
to room temperature and was stirred for another 1 h. The solid was
separated by centrifugation, the yellow solution was concentrated
and the oily residue was stirred in pentane for 12 h, whereby a pale
yellow powder was formed, which was centrifuged off and dried in
vacuo. The solid was dissolved in CH2Cl2 and filtered through ce-
lite. The clear, yellow solution was cooled with liquid nitrogen and
layered with n-pentane. After 2 days pale yellow crystals were ob-
tained which were suitable for X-ray crystallography. Pale yellow
powder, 74 mg (53%). Complex 15 was also prepared from 11 or
13, using the same procedure. 1H NMR (270 MHz, 25 °C, CD2Cl2):
1
1
(s), 6.3 (sat, JP,Pt ϭ 3399 Hz), 37.0 (sat), 21.6 (s), 6.1 (sat, JP,Pt
ϭ
3385 Hz) ppm. IR (KBr): ν˜ ϭ 1776 w, 1714 s, 1654 s, 1438 s cmϪ1
.
C53H42ClNO3P2Pt (1033.4): calcd. C 61.60, H 4.10, N 1.36; found
C 61.21, H 4.06, N 1.23.
cis-Chlorobis[1,2(diphenylphosphanyl)ethane](N-phthaloylphenyl-
alanyl)platinum(II) (19): Complex 18 (220 mg, 0.21 mmol) and
bis(diphenylphosphanylethane) (84 mg, 0.21 mmol) were stirred in
20 mL of benzene at room temperature. After 1 h a clear yellow
solution was obtained. After 1 day stirring the solution was concen-
trated to 5 mL and diethyl ether was added. The resulting precipi-
tate was centrifuged off, washed several times with diethyl ether
and then with pentane and dried in vacuo. Colourless powder.
Yield 131 mg (69%). 1H NMR (270 MHz, 25 °C, CDCl3): δ ϭ
8.20Ϫ6.80 (m, 29 H, PPh2, C6H5, C6H4), 5.07 (m, 1 H, CH), 3.91
3
δ ϭ 7.90Ϫ7.70 (m, 4 H, C6H4), 3.43 (pseudo-t, JP,H ϭ 6.4 Hz, 2
H, CH3), 2.20Ϫ1.20 (m, 48 H, C6H11, CH2CH2) ppm. 31P{1H}
2
NMR (109.4 MHz, 25 °C, CD2Cl2): δ ϭ 83.37 (d, JP,P ϭ 15 Hz,
2
1 P), 71.36 (d, JP,P ϭ 15 Hz, 1 P) ppm. IR (Nujol): ν˜ ϭ 1775,
1725, 1636 cmϪ1. C36H54BF4NO3P2Pd·0.25CH2Cl2 (797.2): calcd.
C 53.11, H 6.89, N 1.76; found C 53.39, H 6.77, N 1.59.
2
3
2
[Bis(2-diphenylphosphanylethyl)phenylphosphane]chloro(N-
phthaloylaminoacetyl)palladium(II) (16): Bis(diphenylphosphanyl-
(dd, JH,H ϭ 14.1 Hz, JH,H ϭ 3.3 Hz, CH2), 2.94 (dd, JH,H ϭ
3
14.1 Hz, JH,H ϭ 13.0 Hz, CH2), 2.30Ϫ1.80 (m, 4 H, CH2CH2)
www.eurjic.org
1338
 2004 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Eur. J. Inorg. Chem. 2004, 1330Ϫ1340

Complexes of PdII, PtII, FeII and ReI with N-Phthaloyl as an Amino Protecting Group
Table 3. Crystallographic data for 2, 11, 14, 15 and 16
FULL PAPER
2
11
14
15
16
Formula
Mr
C16H11FeNO4
337.11
monoclinic
P21/c
8.2954(8)
9.7015(11)
17.635(2)
90
92.108(9)
90
C35H54BrNO2P2Pd C45H36BF4NO2P2Pd C71H110B2Cl2F8N2O4P4Pd2 C50H53Cl3NO3P3Pd
769.04
monoclinic
P21/n
11.8160(10)
19.938(4)
15.5380(10)
90
107.64
90
3488.4(8)
4
877.90
1636.81
triclinic
P1
1021.59
monoclinic
P21/n
17.3883(10)
15.7147(9)
18.4968(10)
90
106.3910(1)
90
Crystal system
Space group
triclinic
¯
¯
P1
˚
a (A)
10.518(3)
12.860(2)
15.348(4)
97.19
11.4737(13)
16.723(2)
21.594(3)
109.956(2)
93.573(2)
103.714(2)
3736.6(8)
2
˚
b (A)
˚
c (A)
α (°)
β (°)
γ (°)
V (A3)
Z
92.90
105.80
1974.0(8)
2
1418.2(3)
4
1.579
4848.9(5)
4
ρcalcd. (g·cmϪ3
)
1.464
1.800
1.477
0.610
1.455
0.706
1.399
0.689
µ (mmϪ1
]
1.080
Crystal size (mm)
2θ range (°)
0.47 ϫ 0.40 ϫ 0.13 0.38 ϫ 0.25 ϫ 0.25 0.40 ϫ 0.35 ϫ 0.30 0.30 ϫ 0.20 ϫ 0.20
0.35 ϫ 0.30 ϫ 0.25
2.84Ϫ58.62
Ϫ22 Յ h Յ 22
Ϫ20 Յ k Յ 20
Ϫ23 Յ l Յ 23
27917
2.31Ϫ24.97
0 Յ h Յ 9
Ϫ11 Յ k Յ 0
Ϫ20 Յ l Յ 20
2678
3.82Ϫ50.00
Ϫ14 Յ h Յ 1
Ϫ23 Յ k Յ 1
Ϫ17 Յ l Յ 18
7505
3.96Ϫ50.32
0 Յ h Յ 12
Ϫ14 Յ k Յ 14
Ϫ14 Յ l Յ 14
6333
2.04Ϫ58.72
Ϫ15 Յ h Յ 11
Ϫ20 Յ k Յ 20
Ϫ26 Յ l Յ 26
22301
Index range
Collected reflns.
Independent reflns.
Rint (%)
2493
61118
5963
11720
9343
0.0243
0.0075
0.0357
0.0193
0.0344
Max./min. transmissions 0.9999/0.8133
1.000/0.825
1592
1.0000/0.8232
1700
1.0000/0.8991
2104
Parameters
688
892
R1/wR2 [F Ͼ 4σ(F)]
GoF
0.0402/0.0791
1.093
0.259/Ϫ0.206
0.0463/0.0927
1.024
0.821/0.514
0.0446/0.1165
1.032
0.653/Ϫ0.783
0.0386/0.0927
0.935
0.556/Ϫ0.582
0.0295/0.0776
0.986
0.529/Ϫ0.469
Largest diff. peak and
Ϫ3
˚
hole [e·A
]
ppm. 31P{1H} NMR (109.5 MHz, 25 °C, CD2Cl2): δ ϭ 42.91 (d,
sat), 35.89 (d, 1 P), 28.85 (d, sat), 1JP,Pt ϭ 4233.9 Hz; 51.89 (d, sat),
32.54 (d, 1 P), 13.17 (d, sat) ppm; JP,Pt ϭ 1539.0, JP,P ϭ 5.9 Hz. 20 mmol), methanol (1 mL, 25 mmol) in 25 mL of NMP, PdBr2
2. Reaction of N-(bromomethyl)phthalimide with Methanol and
Carbon Monoxide: N-(Bromomethyl)phthalimide (1.48 g,
1
2
C43H36ClNO3P2Pt (907.2): calcd. C 56.93, H 4.00, N 1.54; found
C 56.46, H 4.06, N 1.26.
(13.5 mg, 0.05 mol, 0.25 mol %) and PPh3 (27 mg, 0.1 mmol, 0.5
mol %) were reacted at 120 °C under 60 bar CO for 12 h. The
volatile components were removed in vacuo and the residue was
taken up in a saturated aqueous solution of NaHCO3, which was
then extracted twice with ethyl acetate. The combined organic
phases were dried over MgSO4 and the solvent was removed in
vacuo. A sample of 1.0 g of the product (3.5 g) was purified by
chromatography on silica (100 g, elution with hexane/ethyl acet-
ate, 7:3).
Methyl N-Phthaloylglycinate: Rf ϭ 0.28; isolated yield 0.25 g (20%).
1H NMR (400 MHz, 25 °C, [D6]DMSO): δ ϭ 7.90Ϫ8.05 (m, 4 H,
H-aromat.), 4.50 (s, 2 H, H-2), 3.72 (s, 3 H, OCH3) ppm. 13C{1H}
NMR (100 MHz, 25 °C, [D6]DMSO): δ ϭ 168.1 (COOH), 167.1
(C-4), 134.9 (C-4Ј), 131.4 (C-6), 123.5 (C-5), 52.5 (OCH3), 38.8 (C-
2) ppm. IR (KBr): ν˜ ϭ 3475 w, 2977 w, 1774 m, 1751 s, 1727 s,
1423 s, 1399 m, 1374 m, 1224 s cmϪ1. MS (CI, 70 eV): m/z ϭ 219
[Mϩ], 188 [M ϩ Hϩ Ϫ CH3OH], 160 [Mϩ Ϫ CO2CH3], 133, 104,
76.
X-ray Structure Determination: The data in Table 3 were collected
on an Enraf Nonius CAD 4 diffractometer (2), a Siemens P4 dif-
fractometer (for 11, 14) or a Siemens P4 diffractometer with a
SMART area detector (for 15, 16). CCDC-153852 (2), -226832
(11), -226831 (14), -226833 (15) and -226834 (16) contain the sup-
plementary crystallographic data for this paper. These data can be
obtained free of charge at www.ccdc.cam.ac.uk/conts/retriev-
ing.html [or from the Cambridge Crystallographic Data Centre, 12
Union Road, Cambridge CB2 1EZ, UK; Fax: (internat.) ϩ 44-
1223/336-033; E-mail: deposit@ccdc.cam.ac.uk].
Amidocarbonylation Experiments
The general procedure is described in ref.[2]
1. N-Phthaloylglycine: Phthalimide (3.68 g, 25 mmol), para-
formaldehyde (0.76 g, 25 mmol), PdBr2 (16.7 mg, 0.0625 mmol)
and PPh3 (33 mg, 0.125 mg, 0.5 mol %) in 25 mL of N-methylpyr-
rolidine were reacted at 120 °C under 60 bar CO in a 300 mL high-
pressure reactor for 12 h. The product was recrystallised from
water/2-propanol. Isolated yield: 2.82 g (55%); m.p. 193 °C. 1H
NMR (400 MHz, 25 °C, [D6]DMSO): δ ϭ 13.0 (br. s, 1 H, COOH),
7.85Ϫ7.97 (m, 4 H, H-aromat.), 4.32 (s, 2 H, H-2) ppm. 13C{1H}
NMR (100 MHz, 25 °C, [D6]DMSO): δ ϭ 169.0 (COOH), 167.4
(C-4), 134.9 (C-4Ј), 131.5 (C-6), 123.5 (C-5), 39.8 (C-2) ppm. IR
N-(Methoxymethyl)phthalimide: Rf ϭ 0.5; isolated yield 0.70 g
(65%). 1H NMR (400 MHz, 25 °C, [D6]DMSO): δ ϭ 7.88Ϫ7.93
(m, 4 H, H-aromat.), 4.95 (s, 2 H, H-2), 3.28 (s, 3 H, OCH3) ppm.
13C{1H} NMR (100 MHz, 25 °C, [D6]DMSO): δ ϭ 167.8 (C-4),
134.9 (C-4Ј), 131.4 (C-6), 123.6 (C-5), 68.4 (C-2), 52.5 (OCH3)
ppm. MS (CI, 70 eV): m/z ϭ 191 [Mϩ], 160, 133, 104, 76.
(KBr): ν˜ ϭ 2985 m, 2936 w, 1773 s, 1724 s, 1416 s, 1247 s cmϪ1
.
Acknowledgments
MS (CI, 70 eV): m/z ϭ 206 [M ϩ Hϩ], 188 [M ϩ Hϩ Ϫ H2O], 160 Support by the ‘‘Fonds der Chemischen Industrie’’ and by the
[Mϩ Ϫ CO2H], 133, 103.
‘‘Deutsche Forschungsgemeinschaft’’ is gratefully acknowledged.
Eur. J. Inorg. Chem. 2004, 1330Ϫ1340
www.eurjic.org
 2004 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
1339

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