PH-functional o-phosphinophenols - Synthesis via methoxymethylethers and screening tests for Ni-catalyzed ethylene polymerization

Article abstract of DOI:10.1002/hc.20107

Various primary and secondary 2-phosphinoaryl methoxymethylethers were prepared via orthometallation of methyl- and methoxy-substituted aryl methoxymethylethers and subsequent reaction with aminochlorophosphines, followed by alcoholysis and reduction with excess LiAlH₄. Incomplete reduction provides 2-methoxymethoxy-substituted cyclotetraphosphines, isolated and characterized by X-ray crystal structure analysis in one case. An example of the facile P-alkylation of primary to secondary representatives is also given. Secondary 2-phosphinophenols, obtained by selective cleavage of the MOM-protection group, and even the primary 2-phosphino-4-methylphenol react with Ni(COD)₂ to form ethylene polymerization catalysts. 4-Methoxy groups cause a strong increase of the molecular weights and a bimodal molecular weight distribu tion of the polymerization products; neither effect is observed for tertiary phosphinophenolate/Ni polymerization catalysts.

Full text of DOI:10.1002/hc.20107

Heteroatom Chemistry
Volume 16, Number 5, 2005
PH-Functional o-Phosphinophenols—
Synthesis via Methoxymethylethers
and Screening Tests for Ni-Catalyzed
Ethylene Polymerization
Joachim Heinicke,1 Mengzhen He,1 Andrej A. Karasik,2
Igor O. Georgiev,2 Oleg G. Sinyashin,2 and Peter G. Jones3
1Institut fu¨ r Chemie und Biochemie, Ernst-Moritz-Arndt-Universita¨t Greifswald, Soldmannstr
16, 17487 Greifswald, Germany
2A.E. Arbuzov Institute of Organic and Physical Chemistry, Arbuzovstr. 8, Kazan 420088, Russia
3Institut fu¨ r Anorganische und Analytische Chemie, Technische Universita¨t Braunschweig,
Postfach 3329, D-38023 Braunschweig, Germany
Received 11 December 2004
tion of the polymerization products; neither effect
ABSTRACT: Various primary and secondary 2-phos-
is observed for tertiary phosphinophenolate/Ni poly-
phinoaryl methoxymethylethers were prepared via
ꢀ
C
merization catalysts.
2005 Wiley Periodicals, Inc.
orthometallation of methyl- and methoxy-substituted
aryl methoxymethylethers and subsequent reaction
with aminochlorophosphines, followed by alcohol-
ysis and reduction with excess LiAlH4. Incomplete
reduction provides 2-methoxymethoxy-substituted
cyclotetraphosphines, isolated and characterized by
X-ray crystal structure analysis in one case. An
example of the facile P-alkylation of primary to
secondary representatives is also given. Secondary
2-phosphinophenols, obtained by selective cleavage
of the MOM-protection group, and even the primary
2-phosphino-4-methylphenol react with Ni(COD)2 to
form ethylene polymerization catalysts. 4-Methoxy
groups cause a strong increase of the molecular
weights and a bimodal molecular weight distribu-
Heteroatom Chem 16:379–390, 2005; Published online
in Wiley InterScience (www.interscience.wiley.com). DOI
10.1002/hc.20107
INTRODUCTION
P-Tertiary 2-phosphinophenols have found consid-
erable interest as ligands in transition metal com-
plexes [1,2], and organonickel phosphinophenolate
chelate complexes proved to be efficient moisture-
tolerant polymerization or oligomerization catalysts
[1,3,4]. P-Tertiary 2-phosphinophenol ethers became
familiar by the formation of hemilabile P∩O-chelate
complexes [5] and the use of suitable asymmetric
derivatives in highly enantioselective Rh-catalyzed
hydrogenation reactions [6]. Primary [7–9] and sec-
ondary 2-phosphinophenols [9,10], however, have
attracted much less attention. The use of primary
2-phosphinophenols is so far limited to the appli-
cation as building blocks for phosphorus heterocy-
cles [8,9], and secondary 2-phosphinophenols are
Dedicated to Prof. Dr. Alfred Schmidpeter on the occasion of
his 75th birthday.
Correspondence to: Joachim Heinicke; e-mail: heinicke@uni-
greifswald.de.
Contract grant sponsor: Deutsche Forschungsgemeinschaft.
Contract grant sponsor: Fonds der Chemischen Industrie.
2005 Wiley Periodicals, Inc.
c
ꢀ
379

380 Heinicke et al.
known to form dimeric µ-P-bridging nickel phos-
phido complexes [11]. P-alkylation reactions of pri-
mary and secondary to secondary and tertiary 2-
phosphinophenols have been reported, but require
dimetallation and give inadequate yields because
of the hydroxy substituent in o-position. A MOM-
protected secondary 2-phosphinophenol proved to
be more suitable for P-alkylation and thus provided
access to asymmetric P-tertiary derivates, although
reported so far only for 1,3-dibromopropane [9a].
MOM-protection provides also a convenient three-
step synthesis of tertiary 2-phosphinophenols via di-
rect orthometallation of aryl-methoxymethylethers,
phosphinylation, and acidic O-deprotection [12,2i,
3a]. This and the potential use as hybrid ligands
prompted us to study some primary and secondary
2-phosphinophenyl-methoxymethylethers.
substituted aryl methoxymethylethers, the metalla-
tion agent interacts also with the methoxy group
and may lower the selectivity. 4-Methoxyphenyl-
methoxymethylether reacts with n-butyllithium and
ClP(NMe2)2 to 1b in high yield but with slightly lower
selectivity than observed for 1a. About 5% of the
isomer 1bꢁ, formed by metallation in ortho-position
to the methoxy group and subsequent substitution,
was identified by the characteristic coupling pat-
tern of the proton NMR signals. 2-Methoxyphenyl-
methoxymethylether reacts more selectively and
provides only 1c although the statistical chances
for orthometallation next to the MOM and methoxy
groups (1:1) are the same as in 4-methoxyphenyl-
methoxymethylether (2:2). The metallation chances
are no longer equal in the case of 3-methoxyphenyl-
methoxymethylether. The atom H2 in ortho-position
to the MOM and the methoxy group should sta-
tistically be favored to the hydrogen atoms H4 or
H6, while the two alkoxy groups adjacent to the
metallation site may also hinder each other steri-
cally. The experiment shows considerably lowered
selectivity. Lithiation with nBuLi at 0◦C and subse-
quent reaction with ClP(NMe2)2 furnished a 59:41%
mixture of the 3- and 5-methoxy-2-methoxymethyl
benzenephosphonous acid diamides 1d and 1dꢁ. Or-
tholithiation at −78◦C in the presence of TMEDA
improved the selectivity (83:17%) but not enough
to obtain a sufficiently pure isomer. P-Secondary 2-
(aminophenylphosphino)aryl methoxymethylethers
1e [9a] and 1f were obtained by reaction of the cor-
responding lithium reagents with PhP(NMe2)Cl.
RESULTS AND DISCUSSION
Syntheses
4-Methylphenyl-methoxymethylether was treated
with the equimolar amount of n-butyllithium in
diethylether (−40 to −50◦C) and subsequently
with ClP(NMe2)2 to form the MOM-protected 2-
diaminophosphino-4-methylphenol 1a in good yield
and with excellent selectivity (Scheme 1). Isomer sig-
1
nals could not be detected by 31P or H NMR, in-
dicating that the ortholithiation was regiospecific,
controlled only by the MOM group and not influ-
enced by the methyl group. In the case of methoxy-
SCHEME 1

PH-Functional o-Phosphinophenols 381
The conversion of the 2-(aminophosphino)aryl
methoxymethylethers to the corresponding primary
or secondary 2-phosphinoaryl methoxymethylethers
was accomplished by alcoholysis and subsequent re-
duction with lithium aluminum hydride (Scheme 2).
The resistance of the MOM protection group to-
ward alcohols avoids the problem observed in the al-
coholysis of 2-(aminophosphino)phenyl-silylethers,
namely the attack of −P(OR)2 by the deprotected
o-hydroxyl group above 60◦C [8,9], and allows the
isolation of 2a–f by distillation. The reduction to
primary or secondary phosphides, hydrolyzed by
water in work-up to 3a,b or 3e,f, requires excess
LiAlH4. Reduction of crude 2a with only one equiv-
alent of LiAlH4 furnished a small amount of crys-
talline cyclotetraphosphine 4a along with 3a (low
yield) and the corresponding diphosphine, which
underwent disproportionation on heating. Finally,
the facile P-alkylation of primary to secondary 2-
methoxymethyl-arylphosphines, exemplified by the
reaction of 2b with nBuLi and isopropylbromide to
3g, should be mentioned.
Suitable precursors for the reduction to com-
pounds of type 3 can also be prepared directly from
2-lithioaryl methoxymethylethers. While lithium 2-
lithiophenolates generated from O-unprotected phe-
nols react unselectively with 2-chloro-1,3,2-dioxa-
phospholane [13] affording mixtures of mono-, di-,
and triorganophosphines, the reaction of the o-
lithiophenyl-methoxymethylethers proceeds selec-
tively to mono-substitution products, exemplified by
5a (Scheme 3). Similarly, chlorodiethylphosphate
can be used to synthesize the phosphonate 6a, which
is not isolated, and is reduced by LiAlH4 to 3a. How-
ever, the total yield of 3a is no better than in the
synthesis via 1a and 2a. Crude 6a (δ31P 17.7, > 90%
ꢀintens.), obtained from the solution by evaporation
of diethyl ether, is a highly viscous material and de-
SCHEME 3
composes upon distillation attempts in high vacuum.
An analogous attempt with the 2-perhydropyranyl
instead of the MOM-protection group, affording
7a and 8a, respectively, revealed similar behavior
and even lower yields. The complete conversion of
chlorodiethylphosphate, the lack of LiCl precipita-
tion in the ethereal solution, and the thermal behav-
ior could be accounted for by coordination of the
lithium chloride, but this aspect, somewhat related
to alkali metal complexes of (aza)crown ethers with
a phosphine oxide side arm [14], was not studied
within this work.
The O-dealkylation of tertiary 2-phosphinophe-
nyl-methylethers or -isopropylethers is known but
requires prolonged reflux with concentrated aque-
ous HI or HBr [15] or reaction with BBr3 in CH2Cl2
followed by methanolysis [2j]. The deprotection of
MOM-protected tertiary 2-phosphinophenols can be
accomplished under much less drastic conditions,
namely treatment with methanolic hydrochloric acid
at 40◦C [12, 2i, 3a] or even with dilute hydrochloric
acid. This allows selective 2-O-deprotection in the
presence of 4-methoxy groups [3a], also in the case
of the P-secondary 2-phosphino-4-methoxyphenyl
methoxymethylethers 3f and 3g (Scheme 4). The
yield of 9f is rather low but that of 9g is ad-
equate. Deprotection of primary 2-phosphinoaryl
methoxymethylethers was attempted, so far only for
3a and 8a, with acid-charged ion exchange resin
Amberlyst 15H in methanol (4 h 50◦C, 15 h 20◦C)
but led to extensive P C bond cleavage besides O-
deprotection and furnished 9a only in low yield and
contaminated with p-cresol. The P C cleavage in
the absence of water might have been supported by
ortho-directed protonation via the MOM group, facil-
itated by the absence of steric hindrance, but it needs
SCHEME 2

382 Heinicke et al.
SCHEME 4
further studies to clarify whether the decomposition
is due to intra- or inter-molecular processes.
FIGURE 1 Molecular structure of 4a (thermal ellipsoids
˚
with 30% probability). Selected bond lengths (A) and an-
gles (◦): P C(1) 1.8347(17), P P#1 2.2253(6); C(1) P P#1
104.31(6), C(1) P P#2 100.86(6), P#1 P P#2 85.134(13),
P C(1) C(2) 124.99(12), P C(1) C(6) 116.79(13); symme-
Structural Aspects
Structural evidence of the compounds 1–9 is given
by the characteristic 1H, 13C, and 31P NMR data.
The appearance of a phosphorus singlet for the crys-
talline 4a at δ − 58.2 is in accordance with a sym-
metric tetraorganocyclotetraphosphine (PR)4 which
usually display a singlet in the range δ from −45
to −77 [16] while cyclotetramers with organophos-
phorus substituents, e.g. phosphoniumylidyl groups
[17], or other cyclooligophosphines (PR)n exhibit
more complex spectra due to P P coupling [16].
The assignment is confirmed by crystal structure
analysis (Fig. 1). The molecule is a folded four-
membered ring of phosphorus atoms with all-trans
substituents in equatorial positions and possesses 4-
symmetry. The phosphorus atoms are pyramidal (an-
gle sum 290.3◦) and occupy positions alternating 0.32
try transformations used to generate equivalent atoms: #1
1
−y + 14 , x + 41 , −z + 14 ; #2y − 41 , x + 14 , −z + 4
.
and Ni(COD)2 (COD 1,5-cyclooctadiene) or other re-
lated isolated complexes catalyze the polymeriza-
tion or oligomerization of ethylene [3,4]. Ligand
tuning revealed that the polymer chain length in-
creases for various PR2 groups in the order Ph2P <
PhtBuP ≈ PhiPrP < Et2P < tBu2P < iPr2P < cHex2P.
This is accounted for by an increase of the chain
lengths with the basicity of the phosphino groups,
superimposed upon a sterically induced decrease
in the case of α-branched alkyl groups [3a], and
raises the question of the effect of primary and sec-
ondary phosphino groups. Screening tests of the
batch polymerization of ethylene by catalysts pre-
pared in situ from equimolar amounts of ligands
9 and Ni(COD)2 revealed that the primary phos-
phinophenol 9a gives rise to rather low activity, but
secondary 2-phosphinophenols lead to highly active
polymerization catalysts, if suitable conditions are
provided (Table 1). Addition of the brown precat-
alyst solution prepared from 9g and Ni(COD)2 to
a preheated (80◦C) solution of ethylene in toluene
caused instant formation of inactive black nickel but
slow heating (20 to 80◦C in 15–20 min) in the ini-
tial phase in toluene in the presence of ethylene al-
lowed formation of a catalyst that converted 94%
of the ethylene to almost linear polyethylene with
vinyl end groups. The turnover number (4350) was
˚
A above and below the best P4 plane. The contact be-
tween the opposite pairs of phosphorus atom across
˚
the ring is 3.011 A. The folding angle amounts to
133.4◦, the torsion angles are 32.5◦. The torsion an-
gle C(2) C(1) P P#1 is rather small (−18.0◦) and
shows that the aryl planes with the 4-methyl end are
packed approximately in the same direction as one
P P# bond, while the other is nearly perpendicular
(C(2) C(1) P P#2 −105.7◦). The bond lengths and
angles correspond to those of other cyclotetraphos-
phines [16–18].
Polymerization of Ethylene
Organonickel phosphinophenolate chelate comple-
xes formed in situ from tertiary 2-phosphinophenols

PH-Functional o-Phosphinophenols 383
TABLE 1 Polymerization of Ethylene with Catalysts Generated from PH-Functional 2-Phosphinophenols and Ni(COD)2 in
Toluene
C2H4
Polymer Data
mp ( ◦C),
Conditions:
Ligand (µmol),a
Quantity (g),
Conversion (%),
TON (mol/mol)
α-Olefin (%),
Me/Vin,
Me/1000 C
d (g/cm3),
DTA ( ◦C)c
(endo, exo)
Mw, Mn
(g/mol)
Experiment T ( ◦C), p (bar)
Crystallinity (%)
1
2
3
4
5
9a (100), 100, 50 14.8, 31, 1640
9e (114), 120, 47 11.7, 75, 2240
130.5–132, 0.954 122.5, 116
MNMR, 13.000g
>98, 2.2, 2.4g
123–124, n.d.
131, 119
16.400, 8.100d,e n.d.
9f (99) 80, 50
12.2, 70.5, 3100
13.0, 94, 4350
9.6, 51, 790
124–126, 0.96, 85b 133, n.d.
696.800, 7.230d, f 97, 1.2, 2.8b
9g (100) 80, 50
9h (220), 140, 40
129–131, 0.97, 85b 137, n.d.
812.600, 9.500d 95, 2.1, 2.1b
126–128, n.d.
135, 119
18.000, 13.800
96, 1.5, 3.4g
aEquimolar amount of Ni(COD)2.
bDetermined by IR from PE plates (BASF).
cEndothermic peak on heating, exothermic peak on cooling.
dBimodal.
eca. 99% Mw ca. 9.000, ca. 1% Mw ca. 500.000 g/mol.
f Hard polymer layer at the wall of the autoclave Mw 948.000, Mn 21.500.
gDetermined by 1H NMR integration.
limited by the ethylene/catalyst ratio in this case. For
9e, 9f and 2-isopropylphosphino-4-methylphenol 9h
[9a] conversions are lower, but conditions are not
optimized. The low activity of the catalyst in experi-
ment 5 (TON 790) is attributable to the low ethylene/
catalyst ratio along with partial catalyst decompo-
sition at 140◦C. The moderate conversion (51%) at
this high temperature, on the other hand, shows
that the PH-based catalyst does not decompose too
rapidly. The molecular weights of the polyethylenes
obtained in experiments 1–5 are all considerably
higher than those of polyethylenes prepared with 2-
diphenylphosphinophenol/Ni(COD)2 catalysts under
similar conditions [3]. The Mw values accomplished
by the secondary 2-phosphino-4-methylphenolate
catalysts 9e/Ni and 9h/Ni are comparable to those
brought about by 2-diethylphosphinophenolate/Ni
catalysts, while Mw values of HDPE obtained with 2-
phosphino-4-methoxyphenolate catalysts 9f/Ni and
9g/Ni are much higher and by far the highest val-
ues achieved so far with 2-phosphinophenolate/Ni
catalysts. The considerable increase of the Mw val-
ues was not observed with catalysts derived from
4-methoxy-substituted tertiary 2-phosphinophenols;
on the contrary, there the Mw values became strongly
reduced by 4-methoxy groups [3a]. The uncommon
effect of the 4-methoxy group is coupled with a bi-
modal molecular weight distribution and a larger
high-molecular weight fraction, observed also, but
only in traces (estimated ca. 1%), in the polyethy-
lene formed by the 2-phosphino-4-methylphenolate
catalyst 9e/Ni (exp. 2). It is improbable that the ef-
fect is caused by small contaminations of 9f and
9g by the corresponding methoxymethyl ethers, as
these proved to be inactive in the screening tests and
should rather lower the molecular weights, as is typ-
ical for ether and particularly phosphine additives
[3a,4c]. The necessity of removing the O-protection
group to generate nickel catalysts indicates a cru-
–
cial role of P∩O -chelate structures in catalysis with
P-secondary moieties, as is known with P-tertiary 2-
phosphinophenols. This, the same selectivity for lin-
ear α-olefins and the fact that the bimodal molecular
distribution can be caused by stirring problems after
formation of more viscous high polymers, lead us to
propose a mechanism similar to that discussed for
SHOP-type catalysts [19,1a,3] (Scheme 5). However,
the present lack of evidence on P∩O -chelate com-
–
plexes derived from secondary 2-phosphinophenols,
the formation of a dimeric cyclopentadienylnickel µ-
P bridging phosphido complex with free OH from
nickelocene and 3a [11] and the unusual effect of 4-
methoxy groups show that further studies on HP∩O -
–
chelate complexes or on the destiny of the PH-ligands
are required to obtain a more detailed and reliable
picture of the mechanism.
SCHEME 5

384 Heinicke et al.
3
4
1
(dd, JPH = 4.0, J = 2.4 Hz, 1H, 3-H). 31P{ H} NMR
EXPERIMENTAL
(C6D6): δ 98.1.
All manipulations were performed under dry ar-
gon, using Schlenk techniques and freshly dis-
tilled ketyl-dried solvents. The arylmethoxymethyl
ethers [3a,20] and 4-methylphenyl-perhydropyran-
2-ylether [21] were prepared according to known
procedures, other chemicals were purchased. Ethy-
lene (99.5%, Air Liquide) was used without fur-
ther treatment. NMR spectra were recorded at 25◦C
on a multinuclear FT-NMR spectrometer ARX300
(Bruker) at 300.1 (1H), 75.5 (13C), and 121.5 (31P)
2-[Bis(dimethylamino)phosphino]-4-methoxy-
phenyl-methoxymethylether (1b). The reaction bet-
ween 4-methoxyphenyl-methoxymethylether (10.5 g,
62.5 mmol) in diethyl ether (70 mL), nBuLi (1.6 N
in hexane, 39.4 mL, 63 mmol), and chlorobis(di-
methylamino)phosphine (9.7 g, 62.5 mmol) gave
15.5 g (87%) of colorless oily 1b, bp 0.04 Torr/136–
138◦C. Anal. Calcd for C13H23N2O3P (286.31): C,
54.55; H, 8.04; N, 9.78. Found: C, 54.14; H, 8.25;
9.48. MS (70 eV, EI, 35◦C): e/z (%) = 286 (44) [M],
271 (31) [M CH+3 ], 242 (50) [M NMe+2 ], 106 (62)
[MeO C6H+3 ], 58 (100), 45 (77) [CH2OMe+]. 1H-NMR
(C6D6): δ 2.69 (d, 3 JPH = 9.3 Hz, 12H, NMe2), 3.25 (s,
3H, OCH3), 3.41 (s, 3H, OCH3), 4.91 (s, 2H, OCH2O),
6.71 (ddd, 3 J = 8.8, 4 J = 3.1, 5 JPH = 1.7 Hz, 1H, 5-H),
7.09 (dd, 3 J = 8.8, 4 JPH = 4.6 Hz, 1H, 6-H), 7.28 (dd,
1
MHz. Shift references are tetramethylsilane for H
and 13C and H3PO4 (85%) for 31P. Coupling con-
stants, unless indicated otherwise, refer to JHH in
1H and JPC in 13C NMR data. Assignment num-
bers of the phenol ring follow the nomenclature,
those of phenyl- or alkylphosphino groups are de-
noted i, o, m, p and α, β, γ, δ, respectively. IR
spectra were measured on a FTIR-spectrometer
System 2000 (Perkin Elmer), mass spectra on a
single-focusing mass spectrometer AMD40 (Intec-
tra). Melting points were determined in a capillary
and are uncorrected. TG/DTA were carried out with
SETARAM TGDTA 92-16 (5 K/min) under argon)
and elemental analyses with a CHNS-932 analyzer
from LECO using standard conditions. Analyses
of oligomers were performed on a gas chromato-
graph Hewlett Packard 5890, column 30 m HP-5
(crosslinked 5%PhMe silicone), 30–180◦C, 20 min
isotherm, 6◦C/min; percentages given refer to mass%
1
3 JPH = 3.8, 4 J = 3.1 Hz, 1H, 3-H). 13C{ H}(DEPT)
2
NMR (toluene-D8): δ 41.8 (d, J = 17.9 Hz, NMe2),
55.1 (OCH3), 55.8 (OCH3), 95.8 (OCH2O), 114.1,
2
116.2 (CH-5, CH-6), 118.2 (d, JPC = 8.1 Hz, CH-3),
131.4 (d, 1 J = 12.9 Hz, Cq-2), 153.1 (d, 2 J = 15.1 Hz,
1
Cq-1), 155.3 (Cq-4). 31P{ H} NMR (C6D6): δ 97.5.
1b was contaminated by ca. 5% of 3-bis(dime-
thylamino)phosphino-4-methoxyphenyl-methoxy-
methylether 1bꢁ: δ 3.21 (s, OMe), 3.33 (s, OMe),
2.70 (d, 3 JPH = 9.3 Hz, NMe2), 4.94 (s, OCH2O), 6.50
4
(dd, 3 J = 8.8, JPH = 4.7 Hz, 5-H), ca. 7.05 (super-
3
imposed, 6-H), 7.49 (dd, JPH = 3.8, 4 J = 3.1 Hz,
1
(uncorrected). H NMR and GPC measurements of
2-H).
polyethylenes were carried out as described in [3a].
6-[Bis(dimethylamino)phosphino]-2-methoxy-
phenyl-methoxymethylether (1c). The reaction
between 2-methoxyphenyl-methoxymethylether
(13.8 g, 82.1 mmol), nBuLi (1.6 N in hexane, 51.5 mL,
82.5 mmol) and chlorobis(dimethylamino)phos-
phine (12.7 g, 82.2 mmol) gave 19.0 g (81%) of
1c, bp 0.04 Torr/120◦C, mp 35–36◦C after crystal-
lization from n-pentane at −25◦C. Anal. Calcd for
C13H23N2O3P (286.31): C, 54.55; H, 8.04; N, 9.78.
Phosphonous and Phosphinous Amides
2-[Bis(dimethylamino)phosphino]-4-methylphe-
nyl-methoxymethylether (1a). A solution of nBuLi
(1.6 N in hexane, 115 mL, 184 mmol) was slowly
added at −40 to −50◦C to a solution of 4-methyl-
phenyl-methoxymethylether (28.0 g, 184 mmol) in
diethyl ether (200 mL). Stirring was continued while
the solution warmed to room temperature. After
2 h at 20◦C the solution was cooled to −20◦C, then
chlorobis(dimethylamino)phosphine (28.4 g, 184
mmol) dissolved in ether (30 mL) was added drop-
wise. The mixture was stirred for 1 h, the precipitate
was separated, and the solvent was evaporated in
vacuum. The residue was distilled at 94–95◦C/0.04
Torr to give 31.0 g (62%) of colorless 1a. Anal.
Calcd for C13H23N2O2P (270.31): C, 57.76; H, 8.58;
N, 10.36. Found: C, 57.33; H, 8.29; N, 9.85. 1H-NMR
1
Found: C, 54.41; H, 8.14; 9.76. H-NMR (C6D6): δ
3
2.70 (d, JPH = 9.2 Hz, 12H, NMe2), 3.27 (s, 3H,
OCH3), 3.58 (s, 3H, OCH3), 5.29 (s, 2H, OCH2O),
3
4
5
6.58 (dt, J = 8.0, J = 1.5, JPH = 1.5 Hz, 1H, 3-H),
3
4
7.00 (td, J = 8.0, JPH = 1.5 Hz, 1H, 4-H), 7.24 (m,
3
4
1
3 J = 8.0, JPH = 3.7, J = 1.5 Hz, 1H, 5-H). 13C{ H},
CH-COSY NMR (C6D6): δ 41.7 (d, 2 J = 18.1 Hz,
NMe2), 55.4 (OCH3), 57.6 (d, 6 J = 8.3 Hz, OCH3),
98.5 (d, 4 J = 4.1 Hz, OCH2O), 113.2 (CH-3), 123.9
3
2
(C6D6): δ 2.21 (s, 3H, Me), 2.71 (d, JPH = 9.3 Hz,
(CH-4), 124.3 (d, JPC = 5.3 Hz, CH-5), 135.3 (d,
12H, NMe2), 3.26 (s, 3H, OMe), 4.93 (s, 2H, OCH2O),
1 J = 12.0 Hz, Cq-6), 147.6 (d, 2 J = 16.4 Hz, Cq-1),
3
4
5
3
1
6.95 (m, J = 8.3, J ≈ 2.4, JPH ≈ 1.4 Hz, 1H, 5-H),
152.8 (d, J = 1.9 Hz, Cq-2). 31P{ H} NMR (C6D6): δ
7.04 (dd, 3 J = 8.3, JPH = 4.4 Hz, 1H, 6-H), 7.38
97.3. MS (70 eV, EI, 30◦C): e/z (%) = 286 (39) [M+],
4

PH-Functional o-Phosphinophenols 385
271 (21) [M CH+3 ], 243 (19), 242 (49) [M NMe+2 ],
198 (16), 183 (15), 139 (19), 119 (15) [M P(NMe2)+2 ],
106 (60) [MeO C6H+3 ], 76 (31), 58 (100), 45 (58)
[CH2OMe+].
2-(Dimethoxyphosphino)-4-methoxyphenyl-me-
thoxymethylether (2b). Dry methanol (3.8 g,
119 mmol) reacted with 1b (8.5 g, 29.7 mmol) to
give 7.1 g (92%) of colorless liquid 2b, bp 0.04
Torr/101◦C. Anal. Calcd for C11H17O5P (260.23):
C, 50.77; H, 6.58. Found: C, 50.60; H, 6.77. MS
(70 eV, EI, 35◦C): e/z (%) = 260 (30) [M], 245 (51)
[M CH+3 ], 217 (20), 185 (48) [M MOM OMe+], 93
(43) [P(OMe)+2 ], 63 (22), 45 (100) [CH2OMe+].
2-[Bis(dimethylamino)phosphino]-3-methoxy-
phenyl-methoxymethylether (1d). nBuLi (1.7 N in
hexane, 39.5 mL, 67.2 mmol) was added dropwise
at −78◦C to 3-methoxyphenyl-methoxymethylether
(11.2 g, 66.7 mmol) dissolved in diethyl ether
(100 mL), TMEDA was added (7.8 g, 67.1 mmol),
the solution was allowed to warm to 20◦C and
stirred for further 2 h. Then, at −40◦C, chloro-
bis(dimethylamino)phosphine (10.0 g, 64.7 mmol)
was added. The mixture was stirred for 1 h at room
temperature, was filtered, washed and distilled to
give 12.7 g (67.6%) of a mixture of 1d and 1dꢁ
(83:17%), bp 0.04 Torr/128–132◦C. 1d: 1H-NMR
(C6D6): δ 2.76 (d, 3 JPH = 9.2 Hz, 12H, NMe2), 3.23 (s,
3H, OCH3), 3.35 (s, 3H, OCH3), 4.94 (s, 2H, OCH2O),
2b: 1H-NMR (C6D6): δ 3.24 (s, 3H, OMe), 3.39 (d,
3 JPH = 10.7 Hz, 6H, POMe), 3.41 (s, 3H, OMe), 4.91
(s, 2H, OCH2O), 6.79 (ddd, 3 J = 8.9, 4 J = 3.2, 5 JPH
=
3
4
1.1 Hz, 1H, 5-H), 7.04 (dd, J = 8.9, JPH = 4.2 Hz,
1H, 6-H), 7.53 (dd, 4 J = 3.2, 3 JPH = 2.3 Hz, 1H, 3-H).
1
2
13C{ H} (C6D6): δ 52.8 (d, J = 9.5 Hz, POMe), 55.3
2
(OMe), 55.8 (OMe), 95.3 (OCH2O), 116.1 (d, JPC
=
4.6 Hz, CH-3), 116.3, 117.1 (CH-5, CH-6), 130.4 (d,
1 J = 29.0 Hz, Cq-2), 154.0 (d, 2 J = 18.0 Hz, Cq-1),
1
155.2 (Cq-4). 31P{ H} NMR (C6D6): δ 152.8.
2b was contaminated by ca. 5% of 3-dimethoxy-
phosphino-4-methoxyphenyl-methoxymethylether
2bꢁ: 1H-NMR (C6D6): δ 3.18 (s, OMe), 3.31 (s, OMe),
POMe doublet superimposed, 4.86 (s, OCH2O),
3
4
4
6.35 (m, J = 8.2, J = 2.2, JPH = 0.8 Hz, 1H, 6-H),
6.90 (m, 3 J = 8.2, 4 J = 2.3 Hz, 1H, 4-H), 7.06 (m,
3 J = 8.2, JPH = 1.7 Hz, 1H, 5-H). 31P{ H} NMR
4
1
(C6D6): δ 96.7.
4
6.48 (dd, 3 J = 8.9, JPH = 4.2 Hz, 5-H), 7.10 (ddd,
5
3 J = 8.9, 4 J = 3.1, JPH = 1.2 Hz, 6-H), 7.76 (dd,
2-(Dimethylaminophenylphosphino)-4-methoxy-
phenyl-methoxymethylether (1f). The reaction
between 4-methoxyphenyl-methoxymethylether
(26.0 g, 160 mmol) in diethyl ether (250 mL),
nBuLi (1.6 N in hexane, 100 mL, 160 mmol), and
chlorodimethylaminophenylphosphine (29.5 g, 160
mmol) (at −20◦C) gave 39.5 g (80%) of 1f, bp 0.04
Torr/154◦C. 1H NMR (C6D6): δ 2.57 (d, 3 JPH = 9.0 Hz,
6H, NMe2), 3.05 (s, 3H, OCH3), 3.37 (s, 3H, OCH3),
1
4 J = 3.1, 3 JPH = 2.1 Hz, 2-H). 31P{ H} NMR (C6D6): δ
153.1.
6-(Dimethoxyphosphino)-2-methoxyphenyl-meth-
oxymethylether (2c). 2c was synthesized as re-
ported for 2a from 1c (12.2 g, 42.7 mmol) and
dry methanol (5.5 g, 170.6 mmol) to yield 10.2 g
(90%) of 2c, bp 0.04 Torr/102–104◦C. Anal. Calcd
for C11H17O5P (260.23): C, 50.77; H, 6.58. Found:
C, 50.32; H, 6.94. 1H-NMR (C6D6): δ 3.21 (s, 3H,
3
4
4.73 (s, 2H, OCH2O), 6.74 (ddd, J = 8.8, J = 3.1,
5 JPH = 1.1 Hz, 1H, 5-H), 7.08–7.15 (m, 4H, aryl), 7.18
(dd, 3 JPH = 4.2, 4 J = 3.1 Hz, 1H, 3-H), 7.44–7.51 (m,
3
OCH3), 3.39 (d, JPH = 10.7 Hz, 6H, OMe), 3.60 (s,
3
3H, OCH3), 5.33 (s, 2H, OCH2O), 6.58 (dt, J = 8.1,
1
2H, aryl). 31P{ H} NMR (C6D6): δ 58.1.
5
4 J ≈ JPH ≈ 1.1 Hz, 1H, 3-H), 6.97 (td, 3 J = 8.1,
4
7.8, JPH = 0.6 Hz, 1H, 4-H), 7.52 (m, 3 J = 7.8,
Phosphonous and Phosphinous Esters
1
3 JPH = 1.9, 4 J = 1.5 Hz, 1H, 5-H). 13C{ H} NMR
2
2-(Dimethoxyphosphino)-4-methylphenyl-me-
thoxymethylether (2a). Dry methanol (25.0 mL,
0.62 mol) was added to 1a (29.3 g, 108.4 mmol).
Gaseous dimethylamine evolved. The tempera-
ture was slowly increased to 60◦C and kept for
2.5 h to complete the reaction. After evaporation of
methanol in vacuum, the residue was distilled to give
23.8 g (90%) of colorless liquid 2a, bp. 0.04 Torr/
92–96◦C. Anal. Calcd for C11H17O4P (244.23): C,
(C6D6): δ 52.9 (d, J = 10.0 Hz, OMe), 55.3 (OCH3),
57.8 (d, 6 J = 8.3 Hz, OCH3), 98.8 (d, 4 J = 1.8 Hz,
2
OCH2O), 115.0 (CH-3), 122.6 (d, JPC = 4.1 Hz,
1
CH-5), 124.1 (CH-4), 134.6 (d, J = 28.0 Hz, Cq-6),
2
3
148.7 (d, J = 20.6 Hz, Cq-1), 152.4 (d, J = 2.4 Hz,
Cq-2). 31P{ H} NMR (C6D6): δ 153.6. MS (70 eV,
1
EI, 35◦C): e/z (%) = 260 (9) [M+], 259 (17), 245
(28) [M CH+3 ], 217 (31), 199 (19), 185 (36), 93 (51)
[P(OMe)+2 ], 63 (21), 45 (100).
1
54.10; H, 7.02. Found: C, 53.96; H, 7.00. H-NMR
(C6D6): δ 2.14 (s, 3H, Me), 3.22 (s, 3H, OMe), 3.42
2-(Methoxyphenylphosphino)-4-methoxyphenyl-
methoxymethylether (2f). 2f was synthesized as
reported for 2a from 1f (39.5 g, 120 mmol) and dry
methanol (8.0 g, 250 mmol) affording 26.5 g (70%) of
2f, bp 0.1 Torr/142–143◦C. Anal. Calcd for C16H19O4P
(d, 3 JPH = 10.6 Hz, 6H, POMe), 4.92 (s, 2H, OCH2O),
3
4
5
6.97 (m, J = 8.3, J ≈ 2.2, JPH ≈ 0.6 Hz, 1H, 5-H),
3
4
7.03 (dd, J = 8.3, JPH = 3.7 Hz, 1H, 6-H), 7.70 (m,
1H, 3-H).

386 Heinicke et al.
1
3 JPH = 6.9, 4 J = 2.1, J ≈ 0.5 Hz, 1H, 3-H). 31P{ H}
(306.30): C, 62.74; H, 6.25. Found: C, 62.38; H, 6.17.
1H NMR (C6D6): δ 3.01 (s, 3H, OMe), 3.37 (s, 3H,
OMe), 3.43 (d, 3 JPH = 14.1 Hz, 3H, POMe), 4.63, 4.80
(2dAB, 2 J = 6.9 Hz, 2H, OCH2O), 6.71 (ddd, 3 J = 8.9,
4 J = 3.1, 5 JPH = 0.6 Hz, 1H, 5-H), 6.97 (dd, 3 J = 8.9,
NMR (CDCl3): δ = −138.7.
Tetra(2-methoxymethyloxy-5-methylphenyl)cyclo-
tetraphosphane diethylether solvate (4a). Reduction
of crude 2a (27.8 g, 115 mmol) with a smaller excess
of LiAlH4 (5.0 g, 131.6 mmol) and worked up as
above furnished ca. 10 g crude product. Crystals
formed overnight were separated and washed with a
small portion of diethyl ether to give 1.5 g (7%) of 4a,
mp 144–145◦C, medium soluble in Et2O or CDCl3,
less soluble in C6D6. Anal. Calcd for C40H54O9P4
(802.76): C, 59.85; H 6.78. Found: C, 59.48; H, 6.83.
1H NMR (CDCl3): δ 2.33 (s, 12H, 5-Me), 3.28 (s, 12H,
OMe), 5.02 (s, 8H, OCH2O), 6.95 (d, 3 J = 8.3 Hz,
4H, 12-H), 7.03 (dd, 3 J = 8.3, 4 J = 2.0 Hz, 4H,
4-H), 7.92 (d, 4 J = 2.0 Hz, 4H, 6-H); Et2O: 1.21,
3.47 (t, q 3 J = 7.1 Hz). 13C NMR (CDCl3): δ 20.7
(Me), 55.9 (OMe), 94.0 (OCH2O), 112.6 (C-3), 127.7
(Cq-5), 129.6, 130.8 (C-4, C-6), 134.1 (br, Cq-1), 155.5
3
4 JPH = 4.5 Hz, 1H, 6-H), 7.02–7.18 (m, J = 8.0 Hz,
3
3H, Ph), 7.48 (t, JPH = 4.0, 4 J = 3.1 Hz, 1H, 3-H),
1
7.72–7.80 (m, 2H, Ph). 31P{ H} NMR (C6D6): δ 108.4.
(1,3,2-Dioxophospholane)-2-yl-4-methylphenyl-
methoxymethylether (5a). A solution of nBuLi (1.6 N
in hexane, 14.5 mL, 63 mmol) was added slowly
(1 mL/min) at −50◦C to a solution of 4-methyl-
phenyl-methoxymethylether (3.60 g, 23.7 mmol)
in diethylether (40 mL). After warming to room
temperature, it was allowed to stir for further 3–5 h.
Then the suspension was cooled to −80◦C, and
2-chloro-1,3,2-dioxaphospholane (3.0 g, 23.7 mmol)
dissolved in diethyl ether (3 mL) was added within
10 min. After stirring overnight at room tempera-
ture, the mixture was filtered, the solvent removed
in vacuum, and the residue distilled to give 3.3 g
(58%) of 5a, bp 105–110◦C/0.02 Torr. Anal. Calcd.
for C11H15O4P (242.21): C, 54.55; H, 6.24. Found: C,
(br, Cq-2); Et2O: 15.3, 65.8. 31P{ H} NMR (CDCl3):
1
δ − 58.2. Crystal data see Table 2.
1
53.82; H, 6.53. H-NMR (C6D6): δ 2.28 (s, 3H, Me),
3.51 (s, 3H, OMe), 3.97–4.10 (m, 4H, OCH2), 5.21 (s,
TABLE 2 Crystal Data and Structure Refinement of 4a
3
4
2H, OCH2O), 6.97 (dd, J = 8.3, JPH = 3.1 Hz, 1H,
3
6-H), 7.07 (dd, JPH = 2.8, 4 J = 2.2 Hz, 1H, 3-H),
Empirical formula
Formula weight
Temperature
C38H50O9P4
774.66
3
4
7.12 (dd, J = 8.3, J = 2.2 Hz, 1H, 5-H). 13C NMR
(CDCl3): δ = 19.7 (s, CH3), 55.2 (s, OCH3), 63.4 (d,
2 J = 9.4 Hz, POCH2), 93.4 (s, OCH2O), 113.5 (s,
C-6), 128.5 (d, 1 J = 5.9 Hz, C-2), 129.5 (s, C-4), 129.9
143(2) K
˚
Wavelength
0.71073 A
Crystal system
Space group
Unit cell dimensions
Tetragonal
I 41/a
2
(s, C-5), 132.7 (s, C-3), 155.9 (d, J = 14.1 Hz, C-1).
◦
◦
◦
˚
˚
˚
a = 17.6234(14) A α = 90
1
31P{ H} NMR (CDCl3): δ 161.8.
b = 17.6234(14) A β = 90
c = 13.4490(16) A γ = 90
3
˚
Volume
4177.0(7) A
Phosphinoaryl-methoxymethylethers from
Phosphonous and Phosphinous Esters
Z
4
Density (calculated)
Absorption coefficient
F(000)
Crystal size
Theta range for
data collection
Index ranges
1.232 mg/m3
0.230 mm−1
1640
4-Methyl-2-phosphinophenyl-methoxymethyl-
ether (3a). A solution of 2a (22.5 g, 92.1 mmol)
in diethyl ether (100 mL) were added slowly at
0◦C to LiAlH4 (7.0 g, 184.2 mmol) in diethyl ether
(400 mL). After stirring for 12 h at room tempera-
ture, degassed water was added dropwise until the
evolution of hydrogen ceased. The suspension was
filtered, and the solid residue carefully washed with
ether. The filtrate was dried with sodium sulfate, the
solvent was removed, and the residue was distilled
at 56–60◦C/0.03 Torr to give 9.3 g (55%) of highly
air sensitive, colorless 3a. Anal. Calcd for C9H13O2P
0.24 × 0.20 × 0.18 mm3
1.90–28.28◦
−22 < h < 23, −23 < k < 22,
−15 < l < 17
Reflections collected
Independent reflections
Completeness to
24722
2599 [R (int) = 0.1374]
100.0%
theta = 28.00◦
Absorption correction
Refinement method
None
Full-matrix least-squares
on F2
1
Data/restraints/parameters
Goodness-of-fit on F
2599/0/106
1.108
(184.18): P, 16.82. Found: P, 16.5. H NMR (C6D6):
2
δ 2.02 (s, 3H, 4-Me), 3.13 (s, 3H, OMe), 3.91 (d,
Final R indices [I > 2σ(I )]
R indices (all data)
Largest diff. peak and hole
R1 = 0.0447, wR 2 = 0.1228
1 JPH = 201.2 Hz, 2H, PH2), 4.84 (s, 2H, OCH2O), 6.85
R1 = 0.0594, wR 2 = 0.1278
3
4
5
(m, J = 8.3, J = 2.1, JPH = 0.4–0.6 Hz, 1H, 5-H),
−3
˚
0.425 and −0.386 e.A
3
4
6.94 (dd, J = 8.3, JPH = 3.2 Hz, 1H, 6-H), 7.10 (m,

PH-Functional o-Phosphinophenols 387
The NMR spectra of the liquid fraction revealed
mainly 3a along with the corresponding P-secondary
diphosphine NMR: δ31P −87.3, −90.7, rac/meso ca.
1:1; PH δ1H 4.31 (dd, 1 JPH = 221, 2 JPH13 Hz), a small
amount of dissolved 4a and an unknown impurity
with δ31P −7.5.
2(-Isopropylphosphino)-4-methoxyphenyl-meth-
oxymethylether (3g). A solution of nBuLi in hexane
(1.6 N, 29.7 mL, 47.5 mmol) was added dropwise
to a solution of 3b (9.5 g, 47.5 mmol) in diethyl
ether (150 mL) at −40◦C and allowed to warm to
room temperature. Stirring was continued for 1 h
to afford a yellow phosphide solution. After cooling
to −40◦C, isopropyl bromide (5.9 g, 48 mmol) was
added dropwise. The mixture was stirred for 4 h at
20◦C and filtered. The solvent was removed, and the
residue was distilled at 90–92◦C/0.04 Torr to give
8.7 g (76%) of colorless liquid 3g. C12H19O3P (242.3),
MS (70 eV, EI): e/z (%) = 242 (23) [M], 211 (41)
[M+ OMe], 168 (36), 167 (100) [M+ PHiPr], 155
4-Methoxy-2-phosphinophenyl-methoxymethyl-
ether (3b). Using the procedure described for 3a,
3b was synthesized from 2b (27.5 g, 110 mmol) in
diethyl ether (90 mL) and LiAlH4 (7.5 g, 20 mmol)
in diethyl ether (400 mL), yield 15.1 g (71%) of
colorless liquid, bp 77–78◦C/0.04 Torr. Anal. Calcd
for C9H13O3P (200.17): C, 54.00; H, 6.55. Found: C,
54.24; H, 7.00. MS (70 eV, EI): e/z (%) = 200 (10)
1
(40), 124 (28), 45 (35) [CH2OMe+]. H NMR (C6D6):
[M]. H-NMR (C6D6): δ 3.14 (s, 3H, OCH3), 3.26 (s,
δ 1.11 (dd, 3 J = 6.9, JPH = 9.7 Hz, 3H, MeA), 1.13
1
3
3H, OCH3), 3.90 (d, JPH = 201.9 Hz, 2H, PH), 4.81
(dd, 3 J = 7.1, JPH = 16.9 Hz, 3H, MeB), 2.17–2.32
1
3
2
(s, 2H, OCH2O), 6.65 (dd, 3 J = 8.9, 4 J = 3.1 Hz, 1H,
5-H), 6.96 (dd, 3 J = 8.9, 4 JPH = 3.4 Hz, 1H, 6-H), 7.00
(m, 3 J ≈ 7, JPH ≈ 2.7 Hz, 1H, CH), 3.18 (s, 3H,
1
OCH3), 3.31 (s, 3H, OCH3), 4.03 (dd, JPH = 206.9,
(dd, JPH ≈ 6, J = 3.1 Hz, 1H, 3-H). 13C{ H} (C6D6):
3 J = 7.7 Hz, 1H, PH), 4.85, 4.87 (2dAB, J = 6.8 Hz,
3
4
1
2
δ 55.6 (OCH3), 56.0 (OCH3), 95.1 (OCH2O), 114.7,
2H, OCH2O), 6.69 (dd, 3 J = 8.9, 4 J = 3.1 Hz, 1H,
115.1 (CH-5, CH-6), 117.5 (d, JPC = 7.0 Hz, Cq-2),
5-H), 7.02 (dd, 3 J = 8.9, JPH = 3.2 Hz, 1H, 6-H),
1
4
3
4
1
120.5 (d, 2 J = 10.5 Hz, CH-3), 152.1 (d, 2 J = 8.2 Hz,
Cq-1), 154.2 (Cq-4). 31P NMR (C6D6): δ − 137.2 (m,
1 JPH = 202, JPH = 6.7, 3.5 Hz).
7.12 (dd, JPH = 5.9, J = 3.1 Hz, 1H, 3-H). 13C{ H}
(C6D6): δ 22.3 (d, 2 J = 19 Hz, Me), 23.9 (2d, J ≈ 9 Hz,
CH, Me), 55.9 (OCH3), 56.4 (OCH3), 95.9 (OCH2O),
115.6, 115.7 (CH-5, CH-6), 116.3 (d, 1 J = 2 Hz, Cq-2),
3b was contaminated by ca. 5% of the isomer 3-
phosphino-4-methoxyphenyl-methoxymethylether
(3bꢁ): 1H-NMR (C6D6): δ 3.17 (s, OMe), 3.25 (s, OMe),
2
2
122.2 (d, J = 9 Hz, CH-3), 154.0 (d, J = 9 Hz, Cq-
1), 155.5 (d, J = 4 Hz, Cq-4). 31P{ H} NMR (C6D6):
3
1
1
3.89 (d, JPH = 202.1 Hz, PH),4.83 (s, OCH2O), 6.35
δ − 34.0.
(dd, 3 J = 8.9, JPH = 3.4 Hz, 5-H), 7.10 (ddd,
3g was contaminated by ca. 5% of the isomer
3-isopropylphosphino-4-methoxyphenyl-methoxy-
4
3 J = 8.9, 4 J = 3.1, JPH = 1.2 Hz, 6-H), 7.29 (dd,
5
4
1
1
3 JPH = 6.9, J = 3.0 z, 2-H). 31P{ H} NMR (C6D6): δ
methylether (3gꢁ) (cf. 1bꢁ): H-NMR (C6D6): δ 1.00
3
−138.3.
(dd, 3 J = 6.9, JPH = 11.6 Hz, MeA), 1.17 (dd,
3
3 J = 7.0, JPH = 14.8 Hz, MeB), CH superimposed,
1
4-Methoxy-2-(phenylphosphino)phenyl-methoxy-
methylether (3f). Using the procedure described for
3a, 3f was synthesized from 2f (23.3 g, 80 mmol)
in diethyl ether (80 mL) and LiAlH4 (4.6 g, 120
mmol) in diethyl ether (250 mL), yield 8.5 g (41%),
bp 0.04 Torr/130–132◦C. C15H17O3P (276.3), MS
(70 eV, EI): e/z (%) = 276 (23) [M+], 245 (23), 244
(100) [M OMe H+], 231 (28), 229 (30),153 (21), 91
3.25 (s, OMe), 3.36 (s, OMe), 4.08 (dd, JPH = 207.3,
3 J = 7.6 Hz, PH), 4.91, 4.92 (2dAB
,
2 J = 6.8 Hz,
OCH2O), 6.70 (dd, part. superimp., 5-H), 7.09
(dd, 4 J = 3.0 Hz, part. superimp., 6-H), 7.20 (dd,
3 JPH = 5.7, 4 J = 3.1 Hz, 2-H). 31P{ H} NMR (C6D6):
1
δ − 35.4.
Phosphinoaryl-methoxymethylethers via
Intermediate Phosphonates
1
(17), 45 (54) [CH2OMe+]. H NMR (C6D6): δ 3.09 (s,
3H, OCH3), 3.23 (s, 3H, OCH3), 4.788, 4.79 (2dAB
,
1
2 J = 6.8 Hz, 2H, OCH2O), 5.37 (d, JPH = 219.2 Hz,
4-Methyl-2-phosphinophenyl-methoxymethyl-
ether (3a). 4-Methylphenyl-methoxymethylether
(6.63 g, 41 mmol), dissolved in diethyl ether (40
mL), was treated with nBuLi (1.6 N in hexane, 26.0
mL, 41.3 mmol) as described for 5a. The resulting
suspension was cooled to −50◦C and added in small
portions (ca. 1 mL) to a solution of (EtO)2P(O)Cl
(5.9 mL, 40.8 mmol) in diethyl ether (5 mL). After
stirring overnight at 20◦C (31P NMR δ 17.7 (6a),
>90% ꢀint), the suspension was added in small
portions to LiAlH4 (3.0 g, 79.0 mmol) in diethylether
3
4
1H, PH), 6.67 (dd, J = 8.9, J = 3.1 Hz, 1H, 5-H),
6.98 (m, 3 JPH = 6.7, 4 J = 3.1 Hz, 1H, 3-H), 6.99–7.04
1
(m, 4H, aryl), 7.50–7.53 (m, 2H, aryl). 13C{ H} (C6D6):
δ 55.8 (OCH3), 56.3 (OCH3), 95.7 (OCH2O), 116.0,
116.3 (CH-5, CH-6), 121.1 (d, 2 J = 9.2 Hz, CH-3),
127.1 (d, 1 J = 14 Hz, Cq-2), 129.29 (CH-p), 129.30
(d, 3 J = 5.8 Hz, CH-m), 135.2 (d, 1 J = 11.3 Hz, Cq-i),
135.6 (d, 2 J = 18.1 Hz, CH-o), 153.6 (d, 2 J = 10.6 Hz,
3
Cq-1), 155.8 (d, J = 3.8 Hz, Cq-4). 31P NMR (C6D6):
δ −53.2 (d quint, 1 JPH = 220 Hz).

388 Heinicke et al.
(100 mL) at 0◦C. The mixture was stirred for 1 h,
then slowly heated and refluxed for 2 h. After stirring
overnight and cooling to 0◦C, degassed water was
added dropwise until the evolution of hydrogen
ceased. The solid hydroxides were filtered off and
washed with ether, the filtrate was dried with Na2SO4
and distilled to give 3.5 g of 3a, bp 67–72◦C/0.2 Torr,
contaminated by ca. 10% p-cresol (corrected total
yield 42%). (NMR data of 3a as given above.)
tracted with diethyl ether (50 mL). The solvent was
removed in vacuum, and the residue was distilled at
0.02 Torr/130–131◦C to give 0.6 g (30%) of 9f as col-
orless viscous liquid. C13H13O2P (232.2), MS (70 eV,
EI): e/z (%) = 232 (95) [M], 154 (100) [M+ Ph H],
124 (40) [M+ PHPh]. 1H NMR (C6D6): δ 3.26 (s, 3H,
OCH3), 5.06 (s br, 1H, OH), 5.22 (d, 1 JPH = 222.4 Hz,
1H, PH), 6.54 (dd, 3 J = 8.7, 4 JPH = 3.5 Hz, 1H, 6-H),
3
4
6.68 (dd, J = 8.7, J = 3.1 Hz, 1H, 5-H), 6.99–7.12
1
(m, 4H, aryl), 7.37–7.43 (m, 2H, aryl). 13C{ H}(DEPT)
4-Methyl-2-phosphinophenyl-perhydropyran-2-yl
ether (8a). A solution of 4-methylphenyl-perhy-
dropyran-2-yl ether (9.2 g, 47.9 mmol) in diethyl
ether (50 mL) was treated with nBuLi (1.6 N in
hexane, 32.0 mL, 51.2 mmol) as described for
5a. At −50◦C a solution of ClP(O)(OEt)2 (8.46 g,
49.0 mmol) in diethyl ether (7 mL) was added
dropwise, and the mixture was stirred overnight at
(C6D6): δ 55.9 (OCH3), 117.3, 117.8 (CH-5, CH-6),
121.6 (d, 1 J = 15.4 Hz, CH-3), 121.8 (d, 2 J = 11.7 Hz,
Cq-2), 129.2 (CH-p), 129.5 (d, 3 J = 6.0 Hz, CH-m),
134.6 (d, 2 J = 16.5 Hz, CH-o), 134.7 (d, 1 J = 8.3 Hz,
Cq-i), 153.2 (d, 2 J = 8.7 Hz, Cq-1), 154.7 (d, 3 J =
1
6.0 Hz, Cq-4). 31P{ H} NMR (C6D6): δ − 61.8.
2-(Isopropylphosphino)-4-methoxyphenol (9g).
3g (7.2 g, 29.8 mmol) was treated with degassed 2N
hydrochloric acid and worked up as above affording
3.7 g (63%) of 9g as colorless viscous liquid, bp 0.02
Torr/113–114◦C. C10H15O2P (198.2), MS (70 eV, EI):
e/z (%) = 198 (75) [M+], 156 (50) [M iPr+], 124
(100) [M PHiPr+], 77 (35) [Ph+]. 1H NMR (C6D6): δ
1.00–1.18 (m, 6H, MeA, MeB), 2.20–2.26 (m, 3 J = 7.0,
2 JPH ≈ 2.9 Hz, 1H, CH), 3.76 (s, 3H, OCH3), 4.04
1
20◦C. H NMR (CDCl3) assessment of the soluble
part (a very viscous oil after removal of solvent)
indicated ca. 55% of crude 7a besides unconverted
4-methylphenyl-perhydropyran-2-yl ether, while
88% of the dissolved phosphorus compounds are
phosphonates, mainly 7a, δ31P 18.2, 84% ꢀint. The
crude suspension was added in small portions to
LiAlH4 (4.0 g, 105 mmol) in diethyl ether (100 mL)
at 0–5◦C, the mixture was allowed to warm to room
temperature and refluxed for 2 h. Then excessive
LiAlH4 was decomposed by dropwise addition of
degassed water, insoluble components were filtered
off, and the filtrate was dried with Na2SO4. Distilla-
tion and redistillation of the fraction 85–100◦C/0.9
Torr gave 3.8 g of impure 8a (corrected yield 2.7 g,
25%), bp 91–97◦C/0.8 Torr, containing ca. 30% of
4-methylphenyl-tetrahydropyran-2-yl ether.
1
3
(dd, JPH = 207.1, J = 7.8 Hz, 1H, PH), 6.15 (s br,
3
4
1H, OH), 6.81 (dd, J = 8.8, J = 3.1 Hz, 1H, 5-H),
6.84 (dd, 3 J = 8.8, 4 JPH = 2.7 Hz, 1H, 6-H), 6.94 (dd,
3 JPH = 6.0, J = 3.1 Hz, 1H, 3-H). 13C{ H} (C6D6): δ
4
1
13C{ H} (C6D6): δ 21.9 (d, 2 J = 17.7 Hz, iPr), 23.1
1
(d, 2 J = 8.1 Hz, iPr), 23.9 (d, 1 J = 6.1 Hz, iPr),
56.0 (OCH3), 117.0, 117.3 (CH-5, CH-6), 118.8 (d,
1 J = 14.7 Hz, Cq-2), 122.2 (d, J = 10.5 Hz, CH-3),
2
2
3
153.7 (d, J = 10.6 Hz, Cq-1), 154.4 (d, J = 4.6 Hz,
Crude 7a: 1H NMR (CDCl3): δ 1.21 (m, 6H, Me),
1.35–1.90 (m, 6H, CH2), 2.17 (s, 3H, 4-Me), 3.81 (t,
3 J = 10.3 Hz, 2H, OCH2), 3.95–4.20 (m, 4H, POCH2),
5.40 (s, 1H, OCHO), 7.02 (d, 3 J = 7.2 Hz, 6-H), 7.15 (d
Cq-4). 31P{ H} NMR (C6D6): δ − 50.6.
1
Crystal Structure Analysis
4
br, 3 J + J ≈ 8.2 Hz, 5-H), 7.66 (d br, 3 JPH = 15.2 Hz,
Data Collection. A crystal of 4a was mounted on
a glass fiber in inert oil and transferred to the cold gas
stream of the diffractometer (Bruker SMART 1000
CCD). Data were collected with monochromated Mo
Kα radiation.
1
3-H). 31P { H} NMR (CDCl3): δ = 18.2.
1
8a: H NMR (CDCl3): δ 1.50–1.90 (m, 6H, CH2),
2.23 (s, 3H, CH3), 3.55–3.64 (m, 1H, OCH2), 3.83 (d,
1 JPH = 204.2 Hz, 2H, PH2), 3.87 (td, J = 10.1, 3.1 Hz,
1H, OCH2), 5.44 (t, 3 J = 3.0 Hz, 1H, O CH O), 6.94–
7.23 (m, 3H, Ar). 13C NMR (CDCl3): δ = 18.4 (Me),
20.2 (OCH2CH2), 25.1 (OCHCH2), 30.2 (CCH2C), 61.5
(OCH2), 95.8 (OCHO), 113.7 (C-6), 118.4 (d, 1 J =
9.3 Hz, C-2), 129.6 (d, 4 J = 2.3 Hz, C-5), 130.6 (d,
Structure Refinement. The structure was refined
anisotropically on F2 using the program SHELXL-97
(Prof. G.M. Sheldrick, University of Go¨ttingen,
Germany). Hydrogen atoms were included using a
riding model or rigid methyl groups. A badly resolved
region of residual electron density was tentatively
assigned as disordered diethyl ether (the only sol-
vent used to obtain single crystals) but could not be
refined satisfactorily. For this reason, the program
SQUEEZE (part of the PLATON-System: Prof. A.L.
2
3 J = 4.2 Hz, C-4), 135.6 (d, J = 9.7 Hz, C-3), 155.7
1
(d, 2 J = 8.0 Hz, C-1). 31P{ H} NMR (CDCl3): δ 138.2.
4-Methoxy-2-(phenylphosphino)phenol (9f). De-
gassed 2N hydrochloric acid (250 mL) was added to
3f (2.4 g, 8.7 mmol) at 40◦C. The mixture was ex-

PH-Functional o-Phosphinophenols 389
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Spek, University of Utrecht, the Netherlands) was
used in order to remove mathematically the effects
of the solvent.
For selected bond lengths and angles of 4a see
Fig. 1. The crystallographic data are listed in Table 2;
where appropriate, the values refer to the idealized
composition of 1:1 tetraphosphine:ether. Complete
crystallographic data for 4a have been deposited
with the Cambridge Crystallographic Data Centre
as supplementary publication no. CCDC 255528.
Copies of the data can be obtained free of charge
on application to CCDC, 12 Union Road, Cambridge
CB2 1EZ, UK [Fax: (int. code) +44-(1223)/336-033,
e-mail: deposit@ccdc.cam.ac.uk].
Ethylene Polymerization
The corresponding phosphinophenol ligand (Table 1,
ca. 100 µmol) and Ni(COD)2 (ca. 27.5 mg, 100 µmol)
were dissolved, each in 10 mL of toluene, cooled to
0◦C (10 min) and mixed. The mixture was stirred at
room temperature for 5 min and transferred via a
Teflon cannula into the argon-filled stainless steel au-
toclave (75 mL), equipped with a manometer, two
valves, a safety diaphragm, and Teflon-coated mag-
netic stirrer. The autoclave was pressurized (ca. 50
bar ethylene unless indicated otherwise), closed and
after weight control transferred into the preheated
bath. After heating for 12–15 h, cooling to room tem-
perature and weight control, unconverted ethylene
was allowed to escape via a cooling trap (−78◦C,
usually ≤0.1 g butenes condensed). The solvent and
liquid products were separated by flash distillation
at about 80◦C/10−2 Torr. The residual polymer was
stirred for 1 d with methanol/hydrochloric acid (1:1),
thoroughly washed with methanol and dried in vac-
uum. Conversion and characteristic polymer data
are given in Table 1.
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ACKNOWLEDGMENTS
We thank the Fonds der Chemischen Industrie for
gifts of chemicals. Furthermore we thank Prof. Dr.
Dr. h.c. W. Keim for the encouragement of this work,
M. K. Kindermann and B. Witt (Greifswald) for
NMR, N. Peulecke, P. Montag (PPS Mainz, GPC) and
D. Lilge (BASELL, Ludwigshafen, IR plates) for poly-
mer characterization.
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