A novel access to tertiary and secondary ortho-aminophenylphosphines by protected group synthesis and palladium catalyzed P-C coupling reactions

Article abstract of DOI:10.1515/znb-2001-4-504

The dilithium salt 1a formed by ortho-metallation of N-tert-butoxycarbonylaniline (BOC-aniline) 1 with two equivalents of tert-butyllithium reacts with the chlorophosphines Ph_3-n,PCl_n, (n = 1 - 3) to yield the BOC protected ortho-aminophenylphosphines 2 - 4 in high yields. On deprotection of 2 - 4 with trimethylchlorosilane in the presence of phenol the HCl adducts of the ortho-aminophenylphosphines 5 - 7 are formed which may be deprotonated with KOH or NaOH to give the neutral phosphines 5a - 7a. The novel secondary phosphine 8 with two ortho-aminophenyl groups is accessible by cleavage of the P-C bond in 7a with metallic lithium and subsequent hydrolysis. The bifunctional P,N ligands 6 or 6a are alternatively accessible by Pd-catalyzed P-C coupling of ortho-iodoaniline with phenylphosphine. If a 1:1 stoichiometry is employed in the coupling reaction of ortho-iodoaniline and phenylphosphine the chiral secondary phosphine 9 is formed.

Full text of DOI:10.1515/znb-2001-4-504

A Novel Access to Tertiary and Secondary or^o-Aminophenylphosphines
by Protected Group Synthesis and Palladium Catalyzed P-C Coupling
Reactions
Antonella Heßler, Konstantin W. Kottsieper, Stefan Schenk, Michael Tepper,
and Othmar Stelzer
Fachbereich 9, Anorganische Chemie, Bergische Universität-GH Wuppertal,
Gaußstr. 20, D-42097 Wuppertal, Germany
Reprint requests to Prof. Dr. O. Stelzer. Fax: +49 (0)202 439 3053.
E-mail: stelzer@uni-wuppertal.de
Z. Naturforsch. 56 b, 347-353 (2001); received January 12, 2001
tert-Butoxycarbonylaniline, orf/zo-Lithiation, Chlorophosphines
The dilithium salt la formed by ortho-metallation of N-terf-butoxycarbonylaniline (BOC-
aniline) 1 with two equivalents of ter/-butyllithium reacts with the chlorophosphines Ph3_„PCl„
(n = 1 - 3) to yield the BOC protected ort/zo-aminophenylphosphines 2 - 4 in high yields. On
deprotection of 2 - 4 with trimethylchlorosilane in the presence of phenol the HC1 adducts
of the o/t/zo-aminophenylphosphines 5 - 7 are formed which may be deprotonated with KOH
or NaOH to give the neutral phosphines 5a - 7a. The novel secondary phosphine 8 with two
orf/zo-aminophenyl groups is accessible by cleavage of the P-C bond in 7a with metallic lithium
and subsequent hydrolysis. The bifunctional P,N ligands 6 or 6a are alternatively accessible by
Pd-catalyzed P-C coupling of ortho-iodoaniline with phenylphosphine. If a 1:1 stoichiometry
is employed in the coupling reaction of orr/zo-iodoaniline and phenylphosphine the chiral
secondary phosphine 9 is formed.
Introduction
rial for the preparation of derivatives B and C, was
highly desirable. The new synthetic procedure to be
developed should be applicable also to orr/zo-ami-
nophenylphosphines bearing more than one C6H4 -
2 -NH2 substituent per phosphorus atom. Like the
chiral phosphinediamine ligands reported recently
by Yamagishi et al. [7d] these multidentate PN2 or
PN3 ligands should show interesting dynamic P,N
coordination with formation of catalyst complexes
D/D' (M = Rh, Ru, Pd) capable of secondary interac-
tion via the free NFL group with substrates bearing
polar groups (e. g. COOH, C(=0)-R).
Phosphines bearing orf/io-aminophenyl moieties
are typical hemilabile ligands [1] forming com-
plexes with transition metals in different oxidation
states [2]. They have attracted substantial interest
because of their potential to form chelate complexes
with a hinging arm for a ready substitution [31 and
their capability to undergo chelate assisted oxida-
tive addition of the NH2 group to the transition
metal [4].
Of the few orf/zo-aminophenylphosphines known
so far the ligand PI12P-C6H4 -2 -NH2 (A) [5] has
preferably been employed in coordination chem-
istry studies and in catalysis [6]. It is used as a start-
ing material for the synthesis of chiral phosphines
(B) and diphosphines (C) bearing C6H4 -2 -N moi-
eties [7a - 7c]. The rather laborious multistage pro-
cedure (with its moderate yield (ca. 40%)) given by
Cooper etal. [5b] is still mainly used for the synthe-
sis ofPh2P-C6H4-2-NH2 (A). Clearly, an easier and
higher yield synthetic route to this key compound
and its secondary derivative Ph(H)P-CöH4 -2 -NH2
(B, R = H) [7c], which is a versatile starting mate-
h2n ph
HzN Ph
Ph
-I
■••
mi
■v.-
mi
rPhn 1r* *
Ö * ™
( X *
B (R = H, Me)
6 r w
" 6
n r 2
R
R
H2N
NH2
.PPh3-n
* 0 0
\
/
M
M
n Cl
D'
/ ^ \ = (R’HCVi
E (n = 1-3)
*
n = 0, 1;R' = H, Me
M = Rh, Ru, Pd
i-ysi
0932-0776/0 1/0400-0347 $ 06.00 © 2001 Verlag der Zeitschrift für Naturforschung, Tübingen • www.znaturforsch.com
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348
A. Heßler et al. • Tertiary and Secondary ort/zo-Aminophenylphosphines
In context with our ongoing work on polar phos- and /?ara-isomers of structurally related aromatic
phine ligands with resonance stabilized cationic phosphine ligands [12, 13]. The doublets appearing
groups [8] orf/zo-aminophenylphosphines were of at ca. 140 ppm (2: 142.1 ppm (2/(PC) = 18 Hz), 3:
140.7 ppm (27(PC) = 18 Hz), 4: 142.6 ppm (2/(PC) =
18 Hz)) in the 13C {1H} NMR spectra correspond to
the ortho-carbon atoms bearing the N(H)-COOfBu
group as indicated by the larger value of the P-C
coupling constants [14]. The singlets in the ^C j'H }
NMR spectra of 2 - 4 at 6C = 151 - 153 ppm may
be assigned to the carbonyl groups of the BOC pro-
tected amino groups by comparison with the ÖC
(CO) values of BOC-aniline (<3C= 152.7 ppm) [15].
The assignments of the other 13C {1H} NMR reso-
nances could be achieved by comparison with the
pertinent data of Ph3 P [16], BOC-aniline [15] and
those of 5 - 7 or 5a - 7a (see below).
The BOC protecting group in 2 - 4 was
removed by treatment with a 1:3 mixture of
trimethylchlorosilane and phenol yielding the hy-
drochlorides 5 - 7 in good yields. This method has
been developed by Kaiser et al. [17a]. The reaction
is mediated by the adduct of Me3 SiCl and phenol
since at ambient temperature formation of Me3 Si-
OPh is not observed in a mixture of both compo-
nents alone as indicated by NMR studies. Attempts
to deprotect 2 - 4 with trifluoroacetic acid [17b] or
3 N HC1 [17c] were not successful.
The 31P {1H} NMR shift values 6? of 5 - 7 do
not differ significantly from those of 2 - 4. The
31P NMR resonances are shifted, however, signifi-
cantly (16.0 - 43.7 ppm) to high field compared with
the <5P values of the corresponding meta-isomers
[Ph3-,!P(C6H4-3-NH3),?]"+ n Cl~ [8a] the effect be-
ing dependent on the number of orf/io-aminophenyl
groups per phosphorus atom. The 13C {1H} NMR
resonances of the orf/zo-carbon atoms in 5 - 7 are
shifted by ca. 5 - 7 ppm to high field compared with
the corresponding data of 2 - 4.
interest as starting materials for the synthesis of lig-
ands of type E bearing orf/zo-guanidiniumphenyl
moieties.
Protected Group Synthesis ofortho-Aminophenyl-
phosphines Ph^PCCöH^-Nth)« Employing
BOC-Aniline as Starting Material
terZ-Butoxycarbonyl (BOC) protected aniline (1),
which is easily accessible by reaction of aniline with
di-terf-butyl dicarbonate in THF [9], was used as a
cheap starting material for the synthesis the ortho-
aminophenylphosphines Ph3_„P(C6H4-2-NH2)„. It
may be metallated with two equivalents of rBuLi
to yield the dilithium salt la [10] (eq. (1)). In this
special case ortho-metallation is favored by forma-
tion of a six-membered ring system, the second
lithium ion being engaged in coordination of the
oxygen atom of the N=COOfBu unit of la. This
reagent which has widely been employed for the
preparation of C substituted heteroaromatic com-
pounds may successfully be applied in ortho-ami-
nophenylphosphine synthesis. Thus la reacts with
the chlorophosphines Ph3_„PCl„ (n = 1 - 3) to give
the BOC protected orr/jo-aminophenylphosphines
2 - 4 in good yields (eq. (2)).
^(Bu
■0-LKL)n
■o
^ L i( L ) n 1)ClnPPh3.
2) H20 (2)
.PPh3_n
1a (L = THF, n = 1-3)
2-4 (n = 1-3)
Nl-b
NaQH>
nCr W
'W /n
5a-7a (n = 1-3)
Thermal dissociation occurs under the conditions
of running the mass spectra of 5 - 7, the molecular
ions of H35C1 and H37C1 being observed in addition
to the peaks of the molecular ions of the correspond-
ing aminophenylphosphines (5a - 7a) and their frag-
ment ions (e. g. 5: M+-C6Hs-2H, 6: M+-CöH5-H, 7:
M+-C6H4-NH2-2H).
2) Li. THF
3)H20 (5)
Due to the ortho-substitution of the aromatic
rings with the bulky N(H)-COOfBu groups the
31P{1H} NMR resonances of 2 - 4 are shifted to high
field compared with those of Ph3P (<5P= -4.7 ppm)
[11] and the meta-analogs of 2 - 4 [8a], This effect
On treatment with KOH or NaOH in
a
CH2Cl2/water two-phase system the hydrochlo-
rides 5 - 7 can be deprotonated to yield the free
of bulky or/7?o-substituents is generally observed aminophosphines 5a - 7a almost quantitatively. On
deprotonation of 5 - 7 the <$Pvalues are shifted only
on comparison of the <5Pvalues of the ortho-, meta-
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349
A. Heßler et al. ■Tertiary and Secondary ort/zo-Aminophenylphosphines
Synthesis of PH Functional orf/w-Aminophenyl-
about 3 ppm to low field. The deprotonation has,
however, a significant effect on the SC values in the
^C ^H } NMR spectra. While a low field shift of
ca. 15 ppm is observed for the resonances of C2, the
SC values of Cl are shifted to high field on going
from 5 - 7 to 5a - 7a. A similar low field shift of
SC on deprotonation has been observed for the car-
bon atom bearing the nitrogen atom in the anilinium
ions (e. g. C6H5NH3+: SC = 128.6 ppm; C6H5NH2:
SC = 146.7 ppm) [16a].
The mass spectra of 5a and 6a show the molecu-
lar ions M+ appearing with high relative intensities.
The pattern of the fragment ions is virtually iden-
tical to that observed in the mass spectra of 5 or 6,
respectively.
phosphines by Pd-Catalyzed P-C Coupling
Reaction of orf/io-Amino-Iodobenzene with
Phenylphosphine
In addition to the secondary ortho-aminophenyl-
phosphine 8 the unsymmetrically substituted sec-
ondary phosphine 9 was of primary interest as a
building block for the synthesis of multidentate
orf/io-aminophenylphosphines. Recently Wild et al.
[7c] reported a multistage procedure for the prepara-
tion of 9 using Ph2P-C6H4-2-NH2 as starting mate-
rial, the synthesis of which is rather time consuming
and laborious.
HjN
r
ph
K
PhPH2, NEt3
Pd2(dba)3.dppp
NHj
0.5 PhPH2, NEt3
Pd(Ph3P)4, GUAP-3
i-yg
NHs
Synthesis of a Secondary orf/io-Aininophenyl-
phosphine by Reductive P-C Cleavage Reaction
CH3CN, H20, 80 °C *
(f J
CH3CN, 90°C
(6)
(7)
Reductive cleavage of the aromatic P-C bonds
in arylphosphines PAr3 with alkali metals M (M =
Li, Na, K) in liquid ammonia or organic solvents
like THF or dioxane^ is a well established syn-
thetic route to the arylphosphides MPAr2 which may
be transformed into alkyl-arylphosphines and sec-
ondary phosphines. This method, which has been
reported first by Issleib et al. [18a], Aguiar et al.
[18b] and Hewertson et al. [18c] was later devel-
oped further by Budzelaar et al. [19].
Thus cleavage of the aromatic P-C bond in tris-
orf/zo-aminophenylphosphine 7a with lithium metal
in THF and subsequent hydrolysis of the intermedi-
ate lithium phosphide LiP(CöH4 -2 -NH2)2 gave the
secondary phosphine 8, which was purified by frac-
tionated distillation at 180 °C, 0.1 mbar (eq. (5)).
The product thus obtained contains, however, small
quantities (3 - 5%) of 9 (<5P = -59.0 ppm) (see
below) formed by C-N cleavage during the synthe-
sis of 8 or by pyrolysis during distillation. In the
31P{1H} NMR spectrum 8 shows a signal at <*>P=
-73.8 ppm which is split under proton coupling
into a doublet (lJ(PH) = 220 Hz). The 31P{*H}
NMR resonance of diphenylphosphine appears at
much lower field (<5P = -41.1 ppm, ^(PH) =
199.5 Hz) [11].
9
\
\
dppp = Ph2P ~ ^ ^ ^ P P h 2
dba = dibenzylidene acetone
nh^n^-
Ph2PH, NEt3
NHj
\ ---------)
, -P-d-(-P-h-3-P)4l GUAP-3
CH3CN, H20, 80°C
(8)
NMej
3j3Cr
Attempts to synthesize the secondary phosphine
9 by reductive cleavage of the aromatic P-C bond
[18, 19] in 2 with Li in THF were not successful.
No selective cleavage of the P-C(Ph) bond could
be achieved. The analysis of the 31P{1H} NMR
spectrum of the reaction mixture after hydrolysis
indicated the formation of appreciable amounts of
PhPH2 in addition to the desired product.
In a preliminary publication [21] we mentioned
the formation of 9 by Pd catalyzed P-C coupling
reaction. Here we report now the full experimen-
tal details of the metal assisted single-stage syn-
thesis of this compound. Thus treatment of PhPH2
with one equivalent of OAt/zo-iodoaniline in pres-
ence of triethylamine using a 2:1 mixture of tris-
dibenzylideneacetone dipalladium and bis-diphe-
nylphosphinopropane as catalyst gives 9 in high
yield. If two equivalents of orf/zo-iodoaniline are
employed the tertiary phosphine 6a is formed slowly
using Pd(Ph3P)4 as the catalyst [22]. This reaction
The 13C{'H} NMR spectrum of 8 shows, as ex- may also be performed in an acetonitrile/water two-
phase system if a 1:4 mixture of Pd(Ph3P)4 and the
bon atom bearing the NH2 group is shifted to low guanidinium phosphine GUAP-3 ({P[C6H4-3-NH-
pected, six resonances. The signal of the ortho-car-
field compared with the SC value of the nonsub-
stituted carbon atom and the corresponding data in
diphenylphosphine [20] (see experimental part).
C(NH2)(NMe2 )]}3+ 3 Cl") [8a] is used as the water
soluble active catalyst. The effect of the addition of
the guanidinium phosphine to Pd(Ph3P)4 on the re-
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350
A. Heßler et al. ■Tertiary and Secondary or//zo-Aminophenylphosphines
and in the solvents used in Pd catalyzed P-C coupling
reactions were removed thoroughly by repeated freeze-
thaw cycles.
Synthesis of the BOC protected ortho-aminophenylphos-
phines 2 - 4
To 6.13 g (31.7 mmol) of BOC-aniline (1), dissolved
in 75 ml of ether, 44 ml of a 1.6 N solution of tert-
BuLi (69.8 mmol) in «-pentane was added at -20 °C. For
a completion of the lithiation the reaction mixture was
stirred at -20 to -10 °C for 3 h. Thereafter a solution of
7.0 g (31.7 mmol) of PhbPCl in 20 ml of ether was added
at -85 °C and the reaction mixture was warmed to ambient
temperature within 4 h. After stirring for 14 h a saturated
solution of NaCl in 40 ml of water was added. The organic
phase was separated and dried over magnesium sulfate.
The residue obtained afterremoval of all volatiles in vacuo
was recrystallized from 50 ml of n-hexane. - Yield: 8.94 g
(75 %) 2.
Time of reaction [h]
Fig. 1. Conversion vs. time diagram for the formation of
6a from o-iodoaniline and phenylphosphine.
action rate of the formation of 6a is shown in Fig. 1.
The reaction is almost complete after five hours
while in the absence of the guanidinium phosphine
only 50 % of the reactands are consumed.
The 31P {1H} NMR spectrum of 9 shows a sig-
nal at <*>P = -59.0 ppm which is split under pro-
ton coupling into a doublet ('/(PH) = 219 Hz).
The 31P{ 1H} NMR resonance of the correspond-
ing meta-isomer appears at much lower field (SP =
-39.6 ppm, [J(PH) = 220 Hz) [8a]. The 13C {]H}
NMR spectrum of 9 has not been published. It
shows ten resonances the assignment of which has
been achieved by 13C-1H-COSY and 13C-DEPT-
135 NMR experiments and was substantiated by
comparison with the pertinent data of Ph2PH [20]
and aniline [16]. The signal of the ortho-carbon
atom C2 (<$C= 150.2 ppm; 2/(PC) = 8.4 Hz), bearing
the NH2group, is shifted to low field compared with
the SC value of the non-substituted carbon atom C6
in the same ring. The resonances of the ipso-carbon
atom Cl (SC = 116.0 ppm; './(PC) = 10.2 Hz), as
well as of C3 (SC = 115.6 ppm; 37(PC) = 2.0 Hz)
and C5 (SC = 118.6 ppm; 3/(PC) = 8.4 Hz) of the
NH2 substituted ring, however, are shifted by ca.
20 ppm to high field compared to those of C l, C8
and C9 (for the indication of the carbon atoms see
Scheme 1).
3
and 4 were obtained in an analogous manner us-
ing 12.06 g (62.4 mmol) of 1, dissolved in 150 ml of
Et2 0 , 86 ml of the tert-BuLi solution (138.0 mmol) and
5.59 g (31.2 mmol) of PhPCl2 or 15.0 g (77.7 mmol)
of 1, dissolved in 150 ml of Et2 0 , 107 ml of the tert-
BuLi solution (138.0 mmol) and 3.56 g (25.9 mmol)
of PCI3 , respectively. - Yields: 12.3 g (80%) 3, 11.5 g
(73 %) 4.
2: 'H NMR (250.1, 400.1 MHz, CDCI3 ): 6 = 7.0 -
7.4 (arom. H), 1.3 (CH3). - 13C{'H} NMR (100.6 MHz,
CDCI3 ): S = 152.7, 142.1 (7 = 18 Hz), 135.2 (7 = 7 Hz),
134.3, 133.6 (7= 19 Hz), 130.3, 129.1, 128.8 (7 = 7 Hz),
128.5 (J = 10 Hz), 123.6 (7 = 2 Hz), 120.7 (7 = 2 Hz),
80.3, 28.0. - 31P{'H} NMR (161.8 MHz, CDC13): 6 =
-21.2. - MS: (El, 70 eV): m/z = 377 [M+], - C23H24NO2P
(377.4): calcd. C 73.19, H 6.41, N 3.71; found C 73.44,
H 6.64, N 3.99.
3: *H NMR (250.1, 400.1 MHz, CDC13): b = 7.1 -
7.4 (arom. H), 1.4 (CH3). - l3C{'H} NMR (100.6 MHz,
CDCI3): 6 = 151.8, 140.7 (7 = 1 8 Hz), 137.4, 132.9 (7 =
2 Hz), 132.5 (7 = 17 Hz), 129.6, 128.4, 127.9, 127.9
(7 = 7 Hz), 123.1, 120.5, 79.5, 27.3. - 3,P{'H} NMR
(161.8 MHz, CDCI3): 6 = -34.5. - MS: (El, 70 eV): m/z =
492 [M+], - C28H33N2O4P (492.6): calcd. C 68.28, H
6.75, N 5.69; found C 67.54, H 6.67, N 5.18.
4: 'H NMR (250.1, 400.1 MHz, CDC13): 6 = 7.0 -
7.8 (arom. H), 1.7 (CH3). - 13C {1H} NMR (100.6 MHz,
CDCI3): S = 152.8, 142.6 (7= 18 Hz), 133.7 (7 = 3 Hz),
130.9, 129.1, 124.5 (7 = 2 Hz), 122.0 (7 = 2 Hz), 80.6,
28.2. - 31P {1H} NMR (161.8 MHz, CDCI3): 6 = -46.3. -
MS: (El, 7 0 eV): m/z = 607 [ M + l . - G ^ N ^ P (607.7):
calcd. C 64.27, H 7.02, N 6.81 (calcd. for C33H42N3O6P
• 0.5 H20); found C 64.38, H 6.65, N 7.13.
Experimental
For experimental details see ref. [12]. BOC-aniline
(1) [9], phenylphosphine [23b], diphenylphosphine [23a]
and Pd(Ph3P)4 [24] were prepared according to literature
methods. Pd2dba3, Ph2P-(CH2)3-PPh2 and di-terf-butyl
dicarbonate were obtained from Aldrich GmbH and used
without further purification. Oxygen dissolved in NEt3
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A. Heßler et al. ■Tertiary and Secondary orf/zo-Aminophenylphosphines
General procedurefor the synthesis of 5 - 7 by deprotec- aminophenylphosphines 5a - 7a were obtained as color-
351
tion of 2 - 4
less solids in almost quantitative yields.
7a contained small quantities of phenol which could
not be separated completely. The compound therefore
was not obtained analytically pure. It was characterized
by 3iP{'H}, '^ {'H } NMR spectroscopy and mass spec-
trometry.
6a: *H NMR (250.1, 400.1 MHz, CD3OD): b = 7.0 -
7.8 (arom. H). - ,3C{'H} NMR (100.6 MHz, CD3OD):
b = 150.4 (7 = 20 Hz), 134.2 (7 = 5 Hz), 133.9 (7 = 2 Hz),
133.8(7= 19 Hz), 130.4, 128.9, 128.6 (7 = 7 Hz), 118.6
(7 = 2 Hz), 117.5 (7 = 6 Hz), 115.6 (7= 3 Hz). - 31P{'H}
NMR (161.8 MHz, CD3OD): b = -33.9. - MS (El, 70 eV):
m/z = 292 [M+], - C,8Hi7N2P (292.3): calcd. C 69.66,
H 6.17 (calcd. for C,8Hi7N2P H20); found C 69.81,
H 6.35.
The BOC protected orf/7o-aminophenylphosphines 2 -
4 (7.17 g (19.0 mmol) of 2, 6.21 g (12.6 mmol) of 3 or
9.36 g (15.4 mmol) of 4) were added at ambient tempera-
ture to a mixture of 25 ml of a 4 M solution of MesSiCl in
CH2CI2 and 75 ml of a 4 M solution of phenol in CH2CI2.
After a short time the temperature of the reaction mixtures
raised to about 40 °C with evolution of carbon dioxide.
In order to complete the deprotection of the BOC group
the reaction mixtures were stirred for 20 h. Thereafter
all volatiles were removed in vacuo and phenol was des-
tilled off under reduced pressure (60 °C, 0.1 mbar). The
remaining oily residues were washed with 50 ml of ether
and dried in vacuo. The phosphine 7 contained small
quantities of phenol which could not be separated com-
pletely and could therefore not be obtained analytically
pure. It was characterized by 3IP{'H}, '^Cl'H} NMR
spectroscopy and mass spectrometry. - Yields: 4.84 g
(81%) 5, 3.37 g (73%) 6, 5.50 g (86%) 7.
7a: 13C{'H} NMR (100.6 MHz, d6-DMSO): b = 151.8
(7 = 20 Hz), 133.9, 130.5, 117.4, 115.3 (7 = 2 Hz), 115.0
(7 = 4 Hz). - 31P{'H} NMR (161.8 MHz, d6-DMSO):
-45.9. - MS (El, 70 eV): m/z = 307 [M+], - Ci8Hi8N3P
(307.3).
5: IR (KBr pellet): u = 2842 cm-1 (NH, broad). - ]H
NMR (250.1, 400.1 MHz, CD3OD): b = 7.0 - 7.8 (arom.
H). - 13C {‘H} NMR (100.6 MHz, CD3OD): b = 136.3
(7 = 2 Hz), 135.3(7=27 Hz), 134.7 (7 = 7 Hz), 133.4(7 =
20 Hz), 131.4, 129.3, 129.2(7= 19 Hz), 128.8 (7 = 7 Hz),
Synthesis of 8 by reductive P-C cleavage of 7a
3.99 g (13.0 mmol) of the tertiary phosphine 7a as ob-
tained above dissolved in 150 ml of THF was treated at
ambient temperature with 0.48 g (70.0 mmol) of lithium
123.8 (7 = 4 Hz), 123.0. - 31P{1H} NMR (161.8 MHz, shot (activated with ethanol). After 78 h stirring remain-
CD3OD): b = -21.1. - MS: (El, 70 eV): m/z = 277 [M+-
HC1], - Ci8H17C1NP (313.8): calcd. C 68.90, H 5.46, N
4.46; found C 67.96, H 5.68, N 4.76.
ing lithium metal was separated by filtration and the clear
solution was charged with 20 ml of water. The lithium
hydroxide formed was filtered off and all volatiles were
removed from the filtrate. Aniline formed during the re-
action was distilled off at 70 °C, 0.1 mbar. Fractionated
distillation of the remaining residue gave 8 as a color-
less liquid. According to the 31P {1H} NMR spectrum the
product obtained contains small quantities (ca. 4%) of 9.
- Yield: 1.74 g (62%).
8 :B. p. 180 °C/0.1m bar.-13C {‘H} NMR (100.6 MHz,
CDCI3): 6 = 149.7 (7= 10 Hz), 136.2 (7= 16 Hz), 131.1,
130.5 (7 = 8 Hz), 119.4(7 = 6 Hz), 116.1 (7 = 2 H z ).-31P
NMR (161.8 MHz, CDC13): b = -73.8 (7(PH) = 220 Hz).
- MS (El, 70 eV): m/z =216 [M+], - Ci2Hi3N2P (216.2):
calcd. C 6 6 .6 6 , H 6.06, N 12.96; found C 67.35, H 7.00,
N 12.08.
6 : IR (KBr pellet): u = 2792 cm“ 1 (NH, broad). - *H
NMR (250.1,400.1 MHz, D20): 6 = 7.0-7.8 (arom. H). -
13C{'H} NMR (100.6 MHz, D20): b = 136.4, 135.3 (7 =
25 Hz), 133.2 (7= 19 Hz), 132.5, 132.1, 129.7, 129.6,
129.1 (7 = 16 Hz), 129.0 (7 = 7 Hz), 124.3 (7 = 4 Hz). -
31P {1H}NMR (161.8 MHz, D20): b = -36.2. - MS: (El,
70 eV): m/z = 292 [M+-2HC1], - C18H,9C12N2P (365.2):
calcd. C 59.19, H 5.24, N 7.67; found C 58.94, H 5.70, N
7.73.
7: IR (KBr pellet): v = 2842 cm“ 1 (NH, broad). ’H
NMR (250.1, 400.1 MHz, D20): b = 7.0 - 7.8 (arom.
H). - 13C{'H} NMR (100.6 MHz, D20): b = 136.9 (7 =
25 Hz), 136.1, 132.9, 128.8, 124.0 (7 = 7 Hz), 123.7 (7 =
4 Hz). - 31P{'H} NMR (161.8 MHz, D20): b = -49.0. -
MS: (El, 70 eV): m/z = 307 [M+-3HC1]. - Ci8H2iC13N3P
(416.7): calcd. C 51.88, H 5.08; found C 52.94, H 5.18.
Synthesis of 9 by Pd-catalyzed P-C coupling reaction
16.19
g (73.9 mmol) of 2-iodoaniline, 8.14 g
(73.9 mmol) of phenylphosphine and 8.6 g (85.0 mmol)
of triethylamine were dissolved in 100 ml of acetoni-
trile. Oxygen dissolved in this mixture was removed
General procedurefor the deprotonation of 5 - 7
The corresponding phosphines 5 - 7 were added to a by repeated freeze-thaw cycles. A solution of 0.338 g
two-phase system consisting of 30 ml of dichloromethane
and 20 ml of water and stirred for 1 h. Thereafter the
organic phase was separated and dried over magne-
sium sulfate. After removal of the solvent in vacuo the
(0.37 mmol) of Pd2(dba)3 and 0.305 g (0.74 mmol) of
dppp in 20 ml of toluene was added with a syringe fit-
ted with a filter unit (0.2 ^<m porosity) to the reaction
mixture obtained above. The pale brown reaction mixture
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352
A. Heßler et al. • Tertiary and Secondary orf/zo-Aminophenylphosphines
was heated to 90 °C for 7 d. Thereafter 3.4 g (85 mmol)
of NaOH and 40 ml of water were added. After stirring
for 2 h all volatiles were removed in vacuo. The remain-
ing residue was distilled in vacuo yielding the secondary
phosphine 9 as a colorless liquid. - Yield: 11.7 g (78%).
0.14 g (0.12 mmol) of Pd(PPh3)4 and 0.30 g (0.48 mmol)
of GUAP-3 or 0.24 g (0.21 mmol) of Pd(PPh3)4 and 0.53 g
(0.85 mmol) of GUAP-3, respectively, in a 1:1 acetonitrile
/ water mixture (20 ml) were added. After strirring for 7 h
all volatiles were removed in vacuo. The residues were
dissolved in a mixture of 20 ml of dichloromethane and
20 ml of water and the organic phase was separated. After
evaporation of the solvent in vacuo 5a and 6a were ob-
9: B. p.: 120 °C/0.01 mbar.
-
*H NMR (250.1,
400.1 MHz, C6D6): 6 = 6.2 - 7.5 (arom. H), 5.06 (PH,
7(PH) = 219.4 Hz), 3.5 (NH2, broad). - ,3C{'H} NMR
(100.6 MHz, C6D6): 6 = 150.2 (J = 8.4 Hz), 137.9 (J = tained as solids which showed a light brown color due to
elemental palladium metal deposited. 5a and 6a were iso-
lated by filtration, washed with ether and dried in vacuo.
For a further purification 5a and 6a were transformed into
the hydrochlorides (5, 6), which could be deprotonated
to yield the phosphine ligands 5a and 6a (see above). 5a
could be purified alternatively by recrystallization from
ethanol. The phosphine ligands were characterized by
31P{ 1H}, 13C{'H} NMR spectroscopy and mass spec-
trometry (see above). - Yields: 2.05 g (62 %) 5a, 2.62 g
(80 %) 6a.
21.6 Hz), 134.3(7= 10.4 Hz), 132.7 (7 = 15.8 Hz), 131.5,
128.8(7 = 5.6 Hz), 128.2, 118.6 (7= 8.4 Hz), 116.0 (7 =
10.2 Hz), 115.6 ( 7 = 2 Hz). - 31P NMR (161.8 MHz,
C6D6): 6 = -59.0 (7(PH) = 219 Hz). - MS (El, 70 eV):
m/z = 201 [M+], - Ci2H,2NP (201.2): calcd. C 71.63, H
6.01, N 6.96; found C 71.41, H 6.31, N 6.99.
Synthesis of 5a and 6a by Pd-catalyzed P-C coupling
reaction in a two-phase system
To a solution of 2.22 g (11.9 mmol) of diphenylphos-
phine or 1.17 g (10.6 mmol) of phenylphosphine, each
in 30 ml of acetonitrile, 2.61 g (11.9 mmol) or 4.67 g
Acknowledgements
This work was supported by the Deutsche Forschungs-
(21.3 mmol) of 2-iodoaniline and 1.21 g (11.9 mmol) or gemeinschaft and the Fonds der Chemischen Industrie.
2.16 g (21.3 mmol) of triethylamine were added and the
mixtures were heated to reflux. Thereafter a suspension of
Celanese Europe Chemicals GmbH and Clariant GmbH
is thanked for financial support.
[7] a) J. P. Cahill, D. Cunneen, P. J. Guiry, Tetrahedron:
Asymmetry 10,4157 (1999); b) J. Okuda, T. Eberle,
T. P. Spaniol, V. Piquet-Faure, J. Organomet. Chem.
591, 127 (1999); c) C. E. Barclay, G. Deeble, R. J.
Doyle, S. A. Elix, G. Salem, T. L. Jones, S. B. Wild,
A. C. Willis, J. Chem. Soc. Dalton Trans. 1995,
57; C. W. G. Anseil, M. K. Cooper, K. P. Dancey,
P. A. Duckworth, K. Henrick, M. McPartlin, G. Or-
gan, P. A. Rasker, J. Chem. Soc., Chem. Commun.
1985, 437; d) I. Yamada, M. Ohkouchi, M. Yam-
aguchi, T. Yamagishi, J. Chem. Soc., Perkin Trans.
1 1997, 1869; I. Yamada, M. Yamaguchi, T. Yam-
agishi, Tetrahedron: Asymmetry 7, 3339 (1996).
[8] a) A. Heßler, O. Stelzer, H. Dibowski, K. Worm,
F. P. Schmidtchen, J. Org. Chem. 62, 2362 (1997);
b) P. Machnitzki, M. Tepper, K. Wenz, O. Stelzer,
E. Herdtweck, J. Organomet. Chem. 602, 158
(2000); c) D. J. Brauer, K. W. Kottsieper, C. Liek,
O. Stelzer, H. Waffenschmidt, P. Wasserscheid,
J. Organomet. Chem., submitted for publication;
d) P. Wasserscheid, H. Waffenschmidt, P. Mach-
nitzki, K. W. Kottsieper, O. Stelzer, J. Chem. Soc.,
Chem. Commun. 2001, 451.
[1] A. Bader, E. Lindner, Coord. Chem. Rev. 108, 27
(1991); P. Braunstein, F. Naud, Angew. Chem. 113,
703 (2001); Angew. Chem. Int. Ed. Engl. 40, 680
(2001).
[2] J. Pietsch, L. Dahlenburg, A. Wolski, H. Berke,
I. L. Eremenko, J. Organomet. Chem. 495, 113
(1995); F. Tisato, F. Refosco, A. Moresco, G. Ban-
doli, A. Dolmella, C. Bolzati, Inorg. Chem. 34, 1779
(1995); F. Refosco, F. Tisato, G. Bandoli, C. Bolzati,
A. Dolmella, A. Moresco, M. Nicolini, J. Chem. Soc.
Dalton Trans. 1993, 605.
[3] C. S. Sloane, D. A. Weinberger, C. A. Mirkin, Progr.
Inorg. Chem. 48, 233 (1999).
[4] D. Hedden, D. M. Roundhill, Inorg. Chem. 24, 4152
(1985); D. Hedden, D. M. Roundhill, W. C. Fultz,
A. R. Rheingold, J. Am. Chem. Soc. 106, 5014
(1984).
[5] a) M. K. Cooper, J. M. Downes, Inorg. Chem. 17,
880 (1978); b) M. K. Cooper, J. M. Downes, P. A.
Duckworth, Inorg. Synth. 25, 129 (1989).
[6] K. R. Reddy, K. Surekha, G. H. Lee, S. M. Peng, S. T.
Liu, Organometallics 19,2637 (2000); E. Fametti, G.
Nardin, M. Graziani, J. Organomet. Chem. 417, 163
(1991).
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Download Date | 8/29/15 10:51 AM

A. Heßler et al. ■Tertiary and Secondary oft/zo-Aminophenylphosphines
353
York (1984); b) E. Breitmaier, W. Voelter, 13C-NMR
Spectroscopy, Verlag Chemie, Weinheim, New York
(1978).
[9] a) P. Dalla Croce, C. La Rosa, A. Ritieni, J. Chem.
Res. (S) 1988, 346; b) A. L. Moraczewski, L. A.
Banaszynski, A. M. From, C. E. White, B. D. Smith,
J. Org. Chem. 63, 7258 (1998).
[10] J. M. Muchowski, M. C. Venuti, J. Org. Chem. 45,
4798 (1980); P. Stanetty, H. Koller, M. Mihovilovic,
J. Org. Chem. 57, 6833 (1992).
[11] a) S. Berger, S. Braun, H. O. Kalinowski, MP-
NMR-Spektroskopie, vol. 3, Georg Thieme Verlag,
Stuttgart, New York (1993); b) L. Maier, Organic
Phosphorus Compounds, Eds. G. M. Kosolapoff, L.
Maier, Wiley-Interscience, p. 1 New York, London,
Sydney, Toronto (1972).
[12] a) M. Hingst, M. Tepper, O. Stelzer, Eur. J. Inorg.
Chem. 1998,73; b) P Machnitzki, T. Nickel, O. Stel-
zer, C. Landgrafe, Eur. J. Inorg. Chem. 1998, 1029;
c) D. J. Brauer, S. Schenk, S. Roßenbach, M. Tepper,
O. Stelzer, T. Häusler, W. S. Sheldrick, J. Orga-
nomet. Chem. 598, 116 (2000).
[13] F. Bitterer, O. Herd, A. Heßler, M. Kühnei, K. Rettig,
O. Stelzer, W. S. Sheldrick, S. Nagel, N. Rösch,
Inorg. Chem. 35, 4103 (1996).
[14] S. S0rensen, R. S. Hansen, H. J. Jakobsen, J. Am.
Chem. Soc. 94, 5900(1972).
[15] a) C. Greek, L. Bischoff, A. Girard, J. Hajicek, Bull.
Soc. Chim. Fr. 131, 429 (1994); b) F. Navas III,
F. L. M. Tang, L. T. Schaller, M. H. Norman, Bioorg.
Med. Chem. 6, 811 (1998).
[17] a) E. Kaiser, J. P. Tam, T. M. Kubiak, R. B. Merri-
field, Tetrahedron Lett. 29, 303 (1988); b) N. Mat-
sui, S. Chino, S. Sakibara, Bull. Chem. Soc. Jpn. 53,
464 (1980); c) G. L. Stahl, R. Walter, C. W. Smith,
J. Org. Chem. 43, 2285 (1978).
[18] a) K. Issleib, R. Völker, Chem. Ber. 94, 392 (1961);
b) A. M. Aguiar, J. Beisler, A. Mills, J. Org. Chem.
27, 1001 (1961); c) W. Hewertson, H. R. Watson, J.
Chem. Soc. 1962, 1490.
[19] P. H. M. Budzelaar, J. A. van Doom, N. Meiboom,
Reel. Trav. Chim. Pays-Bas 110, 420 (1991).
[20] a) R. Batchelor, T. Birchall, J. Am. Chem. Soc. 104,
674 (1982); ^ C fH } NMR (d6-DMSO) of Ph2PH:
134.2 (J= 10.5 Hz), 133.5 (7= 16.6 Hz), 128.4 (J =
5.2 Hz), 128.2; b) J. A. van Doom, J. H. G. Frijns,
N. Meijboom, Rec. Trav. Chim. Pays-Bas 110, 441
(1991).
[21] O. Herd, A. Heßler, M. Hingst, P. Machnitzki,
M. Tepper, O. Stelzer, Catalysis Today 42, 413
(1998).
[22] O. Herd, A. Heßler, M. Hingst, M. Tepper, O. Stel-
zer, J. Organomet. Chem. 522, 69 (1995).
[23] a) W. Gee, R. A. Shaw, B. C. Smith, Inorg. Synth.
9, 19 (1967); b) F. Pass, H. Schindlbauer, Monatsh.
Chem. 90, 148(1959).
[16] a) H. O. Kalinowski, S. Berger, S. Braun, 13C-NMR
[24] D. R. Coulson, Inorg. Synth. 13, 121 (1972).
Spectroscopy, Georg Thieme Verlag, Stuttgart, New
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