One-pot syntheses of sterically shielded phosphorus ligands by selective stepwise nucleophilic substitution at triphenyl phosphite

Article abstract of DOI:10.1055/s-2005-921758

A general, chlorophosphine-free procedure for the preparation of phosphonites, phosphinites and tertiary phosphines with at least one sterically demanding substituent has been developed. In this modular methodology, successive addition of stoichiometric a

Full text of DOI:10.1055/s-2005-921758

354
FEATURE ARTICLE
One-Pot Syntheses of Sterically Shielded Phosphorus Ligands by Selective
Stepwise Nucleophilic Substitution at Triphenyl Phosphite
P
hosphine
a
Synthesesn Keller, Clemens Schlierf, Christoph Nolte, Peter Mayer,1 Bernd F. Straub*
Department Chemie und Biochemie der Ludwig-Maximilians-Universität München, Butenandtstrasse 5–13 (Haus F), 81377 München,
Germany
Fax +49(89)218077717; E-mail: Bernd.F.Straub@cup.uni-muenchen.de
Received 24 October 2005
Dedicated to Prof. Paul Knochel on the occasion of his 50th birthday
PCl3.5 Due to these cost-efficient large-scale syntheses, a
Abstract: A general, chlorophosphine-free procedure for the prep-
major part of the chemical literature is associated with
phenyl phosphines. Tertiary phosphines (no metal com-
plexes) account for almost 47000 references, thereof more
aration of phosphonites, phosphinites and tertiary phosphines with
at least one sterically demanding substituent has been developed. In
this modular methodology, successive addition of stoichiometric
amounts of carbanionic nucleophiles such as organyllithium re- than 35000 with at least one C6H5 substituent at the phos-
agents to P(OPh)3 at low temperatures leads to selective stepwise
phine, more than 32000 with at least two C6H5 substitu-
substitution of the phenoxide leaving groups. Biphenyl-2-yl, 9-an-
ents at the phosphine, and almost 19000 references are
thryl, and N-arylpyrrol-2-yl nucleophiles have been successfully
related to PPh3 itself.6
employed for the first substitution step. Due to the steric shielding,
Tertiary non-phenyl phosphines with at least two different
substituents typically require the synthesis of chlorophos-
phines RPCl2 or R2PCl from Grignard reagent and PCl3.
The isolation of the hygroscopic, air-sensitive, and toxic
intermediates by extraction from MgCl2 and their separa-
tion is laborious.7 Thus, catalogue prices for, e.g. i-Pr2PCl,
t-Bu2PCl, and Cy2PCl are significantly higher than that of
Ph2PCl by a factor of about 7, 8, and 50, respectively.8
Furthermore, the number of commercially available chlo-
rophosphines is rather limited. Thus, the need for synthet-
ic alternatives of chlorophosphine routes is apparent.
the phosphorus derivatives are sufficiently stable for conventional
aqueous work-up. Due to their phenoxide groups, diphenyl phos-
phonites and phenyl phosphinites usually possess sufficiently high
melting points for the isolation by crystallization.
Key words: biaryls, ligands, metalations, phosphorus, pyrroles
Introduction
Phosphorus ligands are of central importance for organic
synthesis with late transition metal catalysts, such as in
alkene hydroformylation, the Heck reaction, cross-cou-
pling, and alkene hydrogenation.2 The successful synthe-
sis of phosphorus ligands, particularly tertiary
phosphines, phosphinites and phosphonites, is the obvi-
ous precondition for their use (Figure 1).
Particularly sterically demanding substituents at phospho-
rus ligands are often employed to enforce a low coordina-
tion number for the central transition metal.9 Free
coordination sites favor a high catalytic activity and thus
prevent the deactivation of precious catalyst metal as sat-
urated complexes. However, PCl3 tends to oxidize steri-
cally demanding or electron-rich organyllithium
substrates. CeCl3 additive results in a diminished reduc-
tion potential of the organometallic reagent and indeed
leads to a higher yield of, e.g. tri-2-furylphosphine.10 We
searched for an alternative leaving group at the phospho-
rus center. A phenoxide substituent instead of chloride
lowers the oxidation potential, and intermediates are not
prone to Michaelis–Arbuzov rearrangements.11 Triphenyl
phosphite is cheap, non-corrosive non-hygroscopic, and
has already been widely used for the synthesis of phos-
phines with three identical substituents (Scheme 1).12
R2
R2
R1
OPh
R1
OPh
R1
R3
PhO
OPh
OPh
OPh
P
P
P
P
phenyl
tertiary
phosphinite phosphine
triphenyl
phosphite phosphonite
diphenyl
R1, R2, R3 = alkyl, aryl
Figure 1 Phosphorus ligands
Phosphines are typically synthesized by the reaction of
chlorophosphines with organometallic reagents.3 Phos-
phonites and phosphinites are mostly prepared from phe-
nols and chlorophosphines. The phenyl substituent
predominates in phosphine chemistry, because triphe-
nylphosphine is easily obtained from PhCl, Na and PCl3.4
Based thereon, Ph2PCl and PhPCl2 are industrially acces-
sible from thermal dismutation of triphenylphosphine and
Scheme 1 Homoleptic tertiary phosphines from P(OPh)3 in analogy
to Wolfsberger’s and Schmidbaur’s seminal PMe3 synthesis12a
SYNTHESIS 2006, No. 2, pp 0354–0365
0
6
.
0
1
.2
0
0
6
Advanced online publication: 21.12.2005
DOI: 10.1055/s-2005-921758; Art ID: Z21005SS
© Georg Thieme Verlag Stuttgart · New York

FEATURE ARTICLE
Phosphine Syntheses
355
Enantioenriched, chiral phosphines R1R2R3P* (‘Horner
phosphines’) have been synthesized by stepwise substitu-
tion of enantiopure alkoxide substituents.13 However, the
phosphonite precursors were again prepared from chloro-
phosphines. Phosphites have a long-standing reputation of
being nonselective in reactions with carbanions.14 Mix-
tures of P(OPh)3 substrate, mono-, di- and trisubstituted
products are obtained. A large excess of P(OMe)3 is nec-
essary to obtain dimethyl biphenyl-2-ylphosphinite as in
situ substrate for a Michaelis–Arbuzov rearrangement
(Scheme 2).15
12 P(OMe)3
Li
P(OMe)2
O
MeI, ∆
P
OMe
Me
81%
Scheme 2 Suppression of phosphinite formation by use of a large
Emrich and Jolly obtained 1-alkylphospholanes by stoi-
chiometric reaction of alkyllithium and 1,4-dilithiumbu-
tane with P(OMe)3 in 47 to 56% yield.16 We are aware of
excess of P(OMe)3 substrate15
Biographical Sketches
Bernd F. Straub (left) was born in Robert G. Bergman, he moved to the Ph.D. thesis, and received a Synthe-
Heidelberg, Germany, in 1973. He Ludwig-Maximilians-Universität sis Journal award in 2003. His re-
received his diploma in 1998 and his München, where he started his inde- search interests involve mechanisms
doctoral degree in 2000 with Prof. pendent research. He was a member of transition metal catalyzed reac-
Peter Hofmann at the Ruprecht- of the 1992 and 1993 German teams tions such as ruthenium-carbene cat-
Karls-Universität Heidelberg. After a of the IChO (International Chemistry alyzed alkene and enyne metathesis,
postdoctoral year at the University of Olympiad). He obtained the Ru- nickel-catalyzed COT synthesis and
California in Berkeley with Prof. precht-Karls award 2001 for his palladium catalysis.
Jan Keller (top) was born in Bad degree in 2004 with Bernd Straub. In phosphine ligands and their com-
Soden am Taunus, Germany, in the same group, he works towards his plexes, and investigation of their ac-
1979. He studied Chemistry at the doctoral degree. He is interested in tivity in homogeneous catalysis.
Ludwig-Maximilians-Universität
unraveling mechanisms of palladi-
München and obtained his diploma um-catalyzed reactions, synthesis of
Christoph Nolte (middle) was born milians-Universität München in undergraduate student in the Straub
in Munich in 1980. He finished his 2004. He investigated applications of group.
bachelor thesis at the Ludwig-Maxi- the triphenyl phosphite method as an
Clemens Schlierf (right) was born in Rudolf Gompper and Herbert Mayr
Neumarkt, Germany, in 1946. He group.
worked as a chemotechnician in the
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356
J. Keller et al.
FEATURE ARTICLE
only one synthesis in the literature, in which a selective product. Thus, P(OPh)3 must be added to the reaction
substitution at triphenyl phosphite has been realized. In mixture either under efficient stirring or diluted in THF in
the Kagan group, two equivalents of ferrocenyllithium re- order to avoid precipitation of solid triphenyl phosphite
acted with one equivalent of P(OPh)3. The phenyl diferro- (mp 22–24 °C). In the case of P(OPh)3 precipitation, its
cenylphosphinite was isolated as a borane adduct re-dissolution and subsequent reaction at a temperature
(Scheme 3).17
significantly higher than –78 °C would result in low prod-
uct selectivity.
BH3
As examples, we would like to present the synthesis of
diphenyl 9-anthrylphosphonite (1), phenyl 9-anthryl(1-
naphthyl)phosphinite (2), and 9-anthryl(1-naphthyl)phen-
ylphosphine (3) (Scheme 4). Phosphine 3 is primarily of
aesthetic and didactic value and could be abbreviated as
‘3-2-1 phosphine’, according to the number of cycles in its
substituents.
Li
POPh
2
1) + P(OPh)3
2) BH3, THF
2
Fe
Fe
68%
1) + P(OPh)3
2) H3O+
H
P
Br
PMe
2
1) LiAlH4, CeCl3
2) BH3, THF
1) n-BuLi, THF, –78 °C
- BuBr
O
2
Fe
Fe
3) n-BuLi
4) Methylation
5) DABCO
2) P(OPh)3, THF, –95 °C
– LiOPh
60%
Li
Scheme 3 Multistep phosphine synthesis from P(OPh)3 by the
P(OPh)2
Kagan group
– LiOPh
There, however, the third and final substitution for the in-
troduction of a methyl group was performed with a multi-
step sequence comprising reduction, phosphorus
protection by BH3, deprotonation, electrophilic methyla-
tion and deprotection.
1 70%
PhLi, r.t.
PhOP
P
We present here a facile, chlorophosphine-free, and cost
efficient one-pot procedure for the synthesis of sterically
shielded phosphonites, phosphinites, and tertiary phos-
phines with different substituents from triphenyl phos-
phite.
– LiOPh
2 one-pot, isolated 46%
3 one-pot, isolated 66%
Scheme 4 Selective, stepwise synthesis of 9-anthrylphosphorus
derivatives
Results and Discussion
Diphenyl 9-anthrylphosphonite (1) is obtained in 70%
isolated yield or can be used in situ for further substitu-
tion. With sterically non-demanding carbanion nucleo-
philes, P(OPh)3 yields mixtures of phosphite,
phosphonite, phosphinite and phosphine. Selectivity can
thus be achieved only by steric means (vide infra). In the
second step, 1-naphthyllithium replaces another phenox-
ide, and affords phenyl 9-anthryl(1-naphthyl)phosphinite
(2) in an overall isolated yield of 46%. Again, the reaction
mixture can be used in situ for an eventual phosphine syn-
thesis. Thirdly, phenyllithium substitutes the last and least
reactive phenoxide leaving group, to give ‘3-2-1 phos-
phine’ 3 over three steps in 66% isolated yield. Generally,
the third step is critical: Sterically demanding Grignard re-
agents are unable to accomplish a satisfactory conversion
of phosphinites to phosphines.
The usual approach for the synthesis of tertiary phos-
phines is the combination of an organometallic reagent
with chlorophosphines. In the case of unsymmetrically
substituted tertiary phosphines, the preparation of the re-
spective chlorophosphine intermediates is often tedious.
Their hygroscopicity, smell, low melting point, and toxic-
ity lead to an unpleasant work-up und purification proce-
dure. The replacement of the P–Cl moiety by P–OPh
opens the path for more convenient and straightforward
one-pot syntheses of many tertiary phosphines. Two fac-
tors determine the success of the synthesis of a heterolep-
tic tertiary phosphine in a one-pot procedure from
P(OPh)3. A sufficiently sterically hindered substituent has
to be introduced first in order to selectively obtain phos-
phonite product. 2-Biphenylyl, 9-anthryl and N-arylpyr-
rol-2-yl groups have been successfully employed in this
study.
We were able to prepare a single-crystal suitable for an X-
ray diffraction study (Figure 2).1 The structure of 3 illus-
trates the presence of three different substituents at the
phosphorus center, and it is in accordance with the spec-
Furthermore, a low reaction temperature of –78 °C or
even lower is mandatory for achieving a high selectivity
of phosphonite main product over phosphinite side
Synthesis 2006, No. 2, 354–365 © Thieme Stuttgart · New York

FEATURE ARTICLE
Phosphine Syntheses
357
CMe3
troscopic data. The C–P–C angles are in the typical range
of 103° to 106°, the P–C bond lengths of 1.83 Å to 1.85 Å
are no surprise either. The naphthyl substituent is essen-
tially coplanar with the P–C(anthryl) bond (dihedral angle
2.1°), presumably due to the steric demand of the 9-anthr-
yl group.
CMe3
Et2O, r.t.
+ P(OPh)3
3
Li
P
3
CMe3
CMe3
5
65%
Scheme 6 Synthesis of the extremely sterically shielded tris-2-
(4,4¢-di-tert-butylbiphenylyl)phosphine (5)
most shielded phosphines.19 The world record for steric
constraint, however, is presumably tris-9-anthrylphos-
phine or another hexa-ortho-substituted triphenylphos-
phine derivative.20 In the space filling model displayed in
Figure 4,21 the extreme steric shielding of the (white-col-
ored) phosphorus center and its electron lone pair by the
2-biphenylyl substituents is illustrated.
Figure 2 ORTEP ellipsoid model of phosphine 3,18 derived from a
single-crystal X-ray crystallographic study
The maximum steric strain at the phosphorus center that
can be obtained via the triphenyl phosphite method is con-
siderable. This is reflected in the syntheses of tris(2,4,6-
trimethoxyphenyl)phosphine,12b,c di(9-anthryl)(2-meth-
oxyphenyl)phosphine (4), and the tris-2-biphenylylphos-
phine derivative 5 (Schemes 5 and 6).
2 9-AnthrylLi
THF, –85 °C
PhO
P(OPh)3
P
– 2 LiOPh
2-MeOC6H4Li, r.t.
P
Figure 3 ORTEP ellipsoid model18 of phosphine 5, derived from a
single-crystal X-ray crystallographic study. Cocrystallized acetone
solvent, disordered tert-butyl methyl groups, and hydrogen have been
omitted for clarity
OMe
– LiOPh
4
one-pot, isolated 65%
2¢,6¢-Disubstituted biphenyl-2-yl fragments play a major
role in palladium-catalyzed cross-coupling reactions. The
Buchwald group has reported several highly active phos-
phine ligands for Suzuki-type C–C bond formation reac-
tions.22 We thus investigated whether 2-biphenylyl
substituents can be linked selectively to a phosphorus cen-
ter. Indeed, the triphenyl phosphite method renders possi-
ble the facile synthesis of unusual substitution patterns at
a biphenyl-2-ylphosphine fragment (Scheme 7). A central
intermediate is phosphonite 6, which can either be isolat-
ed in 68% yield or used in situ for phosphinite or phos-
phine syntheses. Due to the phenoxide groups, the melting
points of phosphonite and phosphinite intermediates are
Scheme 5 One-pot synthesis of di(9-anthryl)(2-methoxyphen-
yl)phosphine (4)
Phosphine 5 is the only homoleptic phosphorus com-
pound in this study (Scheme 6). The reaction of P(OPh)3
with three equivalents of the lithium reagent at room tem-
perature is essentially instantaneous and 65% isolated
yield can be obtained. The only side product is the biphe-
nyl hydrocarbon. The latter is the only product if the lithi-
ation of the iodo precursor with two equivalents of lithium
metal is performed in THF.
In the single-crystal X-ray structure of phosphine 5, the
ortho-aryl groups are directed towards the phosphorus
lone pair (Figure 3). Compound 5 is apparently one of the
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358
J. Keller et al.
FEATURE ARTICLE
The reaction of phosphonite 6 with an excess of a second-
ary Grignard reagent or a tertiary alkyllithium yields
phosphinites. With tert-butyllithium, phosphinite 10 can
be isolated (Scheme 7). A single-crystal X-ray study has
also been successfully performed for the phosphinite 10
(Figure 6).
Figure 4 Top-view on the phosphorus lone pair of the space-filling
model of phosphine 5.21 Cocrystallized acetone solvent, and disorde-
red tert-butyl methyl groups have been omitted for clarity. Carbon:
black; hydrogen: grey; phosphorus: white
expected to be much higher than those of their chloro-
phosphine analogues (Figure 5).
Figure 6 ORTEP ellipsoid model of phosphinite 10,18 derived from
a single-crystal X-ray crystallographic study
Reaction of 6 with excess PhLi furnishes the diphe-
nylphosphino derivative 7 in 74% overall yield. This par-
ticular compound can also be generated directly with the
commercially available electrophile Ph2PCl. Other dia-
rylphosphines such as the dianisylphosphine 8, however,
would require an analogous chlorophosphine Ar2PCl,
which is by far less easily accessible than the ArLi used in
our P(OPh)3 approach. The low isolated yield of 26% of
analytically pure dianisyl product 8 is mainly caused by
the crystallization work-up procedure. The reaction gives
a significantly better conversion, and a chromatographic
work-up of a borane adduct might well lead to an in-
creased isolated yield. The same is true for the dibu-
tylphosphine 9 that was isolated in 19% yield. Due to the
high solubility of phosphine 9, we recommend to react the
isolated phosphonite 6 with excess n-BuLi (61% isolated
yield), which facilitates crystallization considerably.
As expected, the phosphorus lone pair is directed towards
the 2¢,6¢-dimethoxyphenyl fragment both in phosphonite
6 and phosphinite 10. The POCC dihedral angles amount
to 34.3° (6), 46.9° (10), and 58.5° (6). The non-planar na-
ture of the phenoxy-phosphorus fragment should result in
a decreased conjugation of the oxygen with the phenyl p
system and might thus increase the leaving group capabil-
ity of the phenoxide. The significant steric shielding of the
phosphorus center can be seen in Figure 6. Further nu-
cleophilic attack of a second tert-butyllithium is thus pre-
vented even in the presence of excess carbanion. The
analogous reaction sequence with cyclohexyl Grignard
reagent is sluggish already for the phosphinite formation.
Even with addition of LiCl and 1,4-dioxane, thereby
forming Krasovskiy’s magnesiate reagent,23 leads only to
a small conversion. The 2,4,6-trimethoxyphenyl substitu-
ent is easily linked to the phosphorus once – and only once
– with an overall isolated yield of 58%. For the third and
final substitution, a reactive and sterically unhindered nu-
cleophile such as butyllithium is mandatory. An isolated
yield of 13% of tertiary phosphine 13 is obtained. In addi-
tion to low crystallizability in analogy to dibutylphos-
phine derivative 6, some formation of phosphonium salt
due to the BuBr coproduct is observed. The activity of
these phosphines in palladium-catalyzed cross-coupling
reactions will be reported elsewhere in due course.
In analogy to Buchwald’s biphenyl-2-ylphosphines, the
Beller group used N-arylpyrrol-2-yl substituents.24 Pyr-
roles can be easily obtained by condensation of commer-
cially available dimethoxytetrahydrofuran with anilines.25
The larger outer angles of the five-membered pyrrole cy-
cle result in a decreased steric demand and consequently
in a somewhat diminished selectivity of the first substitu-
tion step. Five to 10% of P(OPh)3 and phosphinite side
Figure 5 ORTEP ellipsoid model of phosphonite 6,18 derived from
a single-crystal X-ray crystallographic study
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FEATURE ARTICLE
Phosphine Syntheses
359
MeO
P
OMe
+ n-BuLi
– n-BuBr
Br
Li
OPh
MeO
OMe
MeO
OMe
OMe
MeO
OMe
12
one-pot, isolated 58%
P(OPh)3
THF, –78 °C
n-BuLi
(MeO)3C6H2Li
OMe
MeO
2 PhLi
P
P(OPh)2
OMe
MeO
OMe
P
OMe
MeO
Bu
OMe
MeO
7
13
6 (68%)
one-pot, isolated 74%
one-pot, isolated 13%
2 2-MeOC6H4Li
t-BuLi
CyMgCl + LiCl
2 n-BuLi
MeO
CMe3
OPh
Cy
P OPh
Bu
Bu
P
P
P
MeO
OMe
MeO
OMe
MeO
MeO
OMe
MeO
OMe
11
8
9
10
one-pot, isolated 26%
61% or one-pot 19%
one-pot, isolated 26%
Scheme 7 Syntheses of phosphorus derivatives with Buchwald’s 2¢,6¢-dimethoxybiphenyl-2-yl substituent
product lead to undesired phosphine products. In the prep- nites and second carbanionic nucleophile can be derived
aration of the diphenanthrylphosphine derivative 14 with from the structure of the respective transition state or in-
an isolated yield of 35%, the side products can be re- termediate. The substitution of leaving groups at a phos-
moved by crystallization (Scheme 8).
phorus center by nucleophiles proceeds with inversion,26
in analogy to the Walden inversion in SN2 reactions at car-
bon electrophiles.27 According to Bent’s rule,28 a trigonal
bipyramidal structure of the respective phosphorus transi-
tion state or intermediate is predicted (Figure 7). The ster-
ic repulsion of the sterically demanding substituent of the
phosphonite on one hand and the incoming nucleophile on
the other hand increases the activation barrier for the
phosphinite formation process. As a consequence, the se-
lectivity towards formation of phosphonites from triphe-
nyl phosphite increases and the suppression of
phosphinite formation can and must be controlled by the
nucleophile stoichiometry.
Li
1) P(OPh)3
N
N
n-BuLi
2) 2 9-Phen-
anthrylLi
TMEDA
P
N
(‡)
14
one-pot, isolated 35%
O
Scheme 8 Synthesis of pyrrol-2-ylphosphine derivative 14
O
P
Mechanism
Nu
The reaction of triphenyl phosphite with less than three
equivalents of a sterically unhindered organometallic re-
agent is unselective and leads to a mixture of phosphite
precursor, phosphonites, phosphinite and phosphine. The
necessity for steric demand of the first carbanion in order
to obtain selective phosphonite formation thus solely re-
lies on steric hindrance. The steric repulsion of phospho-
Figure 7 Proposed trigonal bipyramidal phosphorus environment at
the nucleophilic substitution of diphenyl 9-anthrylphosphonite
The phosphorus electron lone pair is located in an equato-
rial position, while the incoming nucleophile and the phe-
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360
J. Keller et al.
FEATURE ARTICLE
Table 1 31P NMR Group Contributions of Substituents (continued)
noxide leaving group adopt the apical positions. It is
unclear, however, whether a lithium counterion is coordi-
nated to the phosphorus lone pair or is present as a solvent
separated cation.
Substituent at Tertiary Phosphine
2-(Trifluoromethyl)phenyl
2-Chlorophenyl
31P NMR Group Contribution
–6
–7
31P NMR Group Contributions
2,6-Dimethoxyphenyl
–22
–22
2,4,6-Trimethoxyphenyl
2¢,6¢-Dimethoxybiphenyl-2-yl
The Van Wazer group and the Grim group found that the
influence of substituents on d is additive.29,30 The accura-
cy is particularly exact for tertiary phosphines.3b,31 We
wish to support the development of this highly useful tool
for the prediction of 31P NMR chemical shifts. A signifi-
cantly extended list of group contributions is summarized
–12 for dialkylphosphino,
–7 for diarylphosphino and
alkylarylphosphino fragments
N-Arylpyrrol-2-yl
–25
–26
–28
–9
below (Table 1). Entries were either taken from analogous N-Arylindol-2-yl
tables from the literature,3b,30,31 or they are based on spec-
3-Furyl
tra of phosphines synthesized in this study.
2-Biphenylyl
Table 1 31P NMR Group Contributions of Substituents
1-Naphthyl
–11
+21
–46
Substituent at Tertiary Phosphine
31P NMR Group Contribution
Acetyl
Cyano
Methyl
–21
Ethyl
–7
Propyl; Isopropyl
–11; +6
The prediction of chemical shifts is straightforward. For
example, the observed 31P chemical shift of the ‘3-2-1
phosphine’ 3 is d = –28.4, which is consistent with the
sum of the group contributions of 9-anthryl (–15), 1-naph-
thyl (–11), and phenyl (–3). The absolute predictive accu-
racy is usually within a deviation of Dd = 3 ppm and only
rarely exceeds Dd = 6 ppm. We are not aware of any ex-
amples with a deviation of Dd >10 ppm.
Butyl; Isobutyl; sec-Butyl; tert-Butyl –11; –14; +2; +20
n-Alkyl (n >2)
Neopentyl
–11
–18
Cyclopentyl
0
Cyclohexyl
+2 (equatorial); –11 (axial)
In phosphine syntheses, selectivity and yield can be esti-
mated by identifying 31P NMR signals from reaction mix-
tures. Furthermore, the consistency of literature data can
be critically evaluated.31 Table 1 does not apply to deriv-
atives with phosphorus bonds to electronegative hetero-
elements such as I, Br, Cl, F, O, or N. The prediction of
31P chemical shifts for primary phosphines requires anoth-
er scaling.3b Different group contributions apply for qua-
ternary phosphonium salts.32
Benzyl
–4
Vinyl
–7
Ethynyl
–31
–3
Phenyl
4-(Trifluoromethyl)phenyl
4-Alkylphenyl, 4-Halophenyl
4-(Dimethylamino)phenyl
3-Anisyl
–2
–3
–4
Advantages
–1
The advantages of this procedure are the one-pot synthetic
protocol, and the facile aqueous, non-inert gas work-up.
The use of toxic, expensive, and hygroscopic chlorophos-
phines can thus be avoided. Filtration from precipitated
magnesium or lithium salts under inert-gas conditions is
not necessary for sterically shielded phosphonites and
phosphinites. In contrast, it is necessary for the analogous
chlorophosphines. Due to the phenoxide substituent(s) in
phosphonites and phosphinites, the melting points are sig-
nificantly higher than for the corresponding chlorophos-
phines. As a consequence, isolation and purification of
intermediates by crystallization is rendered possible in the
P(OPh)3 approach.
3-Halophenyl, 3-Alkylphenyl
Pentafluorophenyl
2-Tolyl
–2
–26
–10
–13
–15
–12
–12
–12
Mesityl
9-Anthryl
9-Phenanthryl
Ferrocenyl
2-Anisyl
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FEATURE ARTICLE
Limitations
Phosphine Syntheses
361
Diphenyl 9-Anthrylphosphonite (1); Typical Procedure
A flame-dried Schlenk flask containing a magnetic stir bar was
charged with 9-bromoanthracene (1.0 g, 3.89 mmol) and THF (50
mL). The solution was cooled to –78 °C, and 1.5 M n-BuLi (2.7
mL, 4.05 mmol, 1.04 equiv) was added dropwise via syringe over
1 min. The resulting suspension was stirred for 10 min. To the mix-
ture, cooled to –95 °C in an acetone/liquid nitrogen cooling bath,
was added P(OPh)3 (1.15 g, 3.7 mmol, 0.95 equiv) in THF (4 mL)
with vigorous stirring to avoid precipitation of P(OPh)3 (Caution!
The liquid nitrogen must not contain O2. Mixtures of liquid oxygen
with organic solvents such as acetone are explosive34). The temper-
ature of the reaction mixture was allowed to slowly reach r.t. The
reaction was complete after the suspension became a clear solution.
The mixture can either be used in situ for further substitution reac-
tions or the phosphonite 1 can be isolated. Only for isolation of the
The methodology is confined to the synthesis of phospho-
rus ligands with either one or two sterically demanding
substituents. In the first substitution step, a sterically de-
manding nucleophile is mandatory in order to obtain a se-
lective monosubstitution. Biphenyl-2-yl, 9-anthryl, and
N-arylpyrrol-2-yl nucleophiles have been successfully
employed. Smaller carbanions such as 1-naphthyllithium,
however, lead to product mixtures. For the third substitu-
tion step, strongly nucleophilic alkyllithium reagents are
mandatory. While steric shielding and large Tolman an-
gles in the phosphine product are often possible (e.g. com-
pound 5, see Scheme 6 and Figures 3 and 4), steric phosphonite, the reaction mixture was quenched with H2O (1 mL),
and the THF was removed in vacuo using a rotary evaporator with-
congestion in dialkylphosphino target compounds still re-
out inert gas conditions. H2O was added, and the phosphonite prod-
quires the use of chlorophosphines.
uct was extracted with Et2O from the aqueous phase. The ethereal
phase was dried (Na2SO4), filtered and crystallized at 5 °C from
Et2O. Yellow microcrystalline powder; recrystallized from Et2O;
Conclusions and Outlook
isolated yield of analytically pure material: 70%; mp 121–124 °C.
IR (KBr): 3049 (w), 1948 (w), 1621 (w), 1592 (m), 1550 (w), 1514
(w), 1490 (s), 1452 (w), 1306 (w), 1213 (s), 1197 (s), 1160 (m),
1152 (m), 1104 (w), 1069 (w), 1022 (w), 949 (w), 922 (w), 905 (w),
895 (m), 874 (s), 846 (s), 820 (m), 776 (m), 764 (w), 738 (s), 712
(m), 688 (m), 668 (w), 612 (w), 598 (w), 581 (w), 560 (w), 523 (w),
498 cm–1 (m).
The substitution of phenoxide in triphenyl phosphite by a
sterically demanding organolithium derivative at low
temperatures selectively results in a diphenyl phospho-
nite. The latter can either be isolated or further trans-
formed into a phenyl phosphinite or a phosphine. Since
phosphorus ligands in homogeneous catalysis often fea-
ture at least one sterically demanding substituent, our
method delivers a strategy for the rapid and cost-efficient
synthesis of interesting ligands. Furthermore, the possibil-
ity to easily isolate phosphonites and phosphinites by
crystallization can be of high importance for combinatori-
al catalyst screening of phosphinites and phosphines with
two or three different substituents. Of course, chlorophos-
phines will not become obsolete in the future. However,
our methodology might compete in some significant
fields of phosphorus ligand syntheses with today’s near-
monopoly use of chlorophosphine intermediates.
3
1H NMR (399.94 MHz, C6D6): d = 6.79 (tqpseudo, JH,H = 7.4 Hz, 2
H, p-H), 6.96 (tpseudotpseudo, J = 8 Hz, J = 2.4 Hz, 4 H, m-H), 7.16
(dm, J = 7.5 Hz, 4 H, o-H), 7.24 (ddd, 3JH,H = 8.5 Hz, 3JH,H = 6.5 Hz,
3
3
4JH,H = 1 Hz, 2 H, 3,6-H), 7.39 (ddd, JH,H = 9 Hz, JH,H = 6.5 Hz,
4JH,H = 1 Hz, 2 H, 2,7-H), 7.76 (dd, JH,H = 8.5 Hz, JH,H = 1 Hz, 2
H, 4,5-H), 8.22 (s, 1 H, 10-H), 9.71 (ddd, JH,H = 9 Hz, JP,H = 3.3
3
4
3
4
Hz, 4JH,H = 1 Hz, 2 H, 1,8-H).
13C{1H} NMR (100.58 MHz, C6D6): d = 120.2 (d, 3JP,C = 9.4 Hz, o-
4
CH), 123.8 (s, p-CH), 125.5 (s, 3,6-CH), 127.0 (d, JP,C = 2.5 Hz,
3
2,7-CH), 127.0 (d, JP,C = 29.4 Hz, 1,8-CH), 129.6 (s, 5,6-CH),
3
130.0 (s, m-CH), 131.8 (d, JP,C = 4.4 Hz, 4¢,10¢-Cq), 132.6 (d,
1JP,C = 27.5 Hz, 9-CqP), 133.1 (s, 10-CH), 134.9 (d, 2JP,C = 17.5 Hz,
8¢,9¢-Cq), 156.4 (d, 2JP,C = 10.6 Hz, POCq).
31P{1H} NMR (80.95 MHz, C6D6): d = 171.0.
MS (EI): m/z (%) = 394.2 (26.67, [M+]), 301.1 (100, [(M – OPh)+]),
317.1 (1, [(M – Ph)+]), 223.1 (14.19, [(M – OPh, – Ph)+]), 207.1
(16.9, [(M – 2 OPh)+]).
Reagents obtained from commercial suppliers were tested for iden-
tity and were used without further purification unless otherwise not-
ed. All reactions were performed with standard Schlenk technique
under N2. THF, 1,4-dioxane, and Et2O were freshly distilled from
sodium/benzophenone under N2 before use.
Anal. Calcd for C26H19O2P: C, 79.18; H, 4.86. Found: C, 78.96; H,
4.70.
The molarity of the organometallic nucleophiles was determined by
the menthol/1,10-phenanthroline method.33
Phenyl 9-Anthryl(1-naphthyl)phosphinite (2); Typical Proce-
dure
1H NMR, 1H-1H-COSY, HSQC, 13C{1H} NMR, and 31P{1H} NMR
were recorded in CDCl3, C6D6 or acetone-d6 on Varian MERCU-
RY-200, Bruker ARX 300, Varian INOVA-400, and Bruker AMX
600 spectrometers. The reported chemical shifts are internally cali-
brated on tetramethylsilane [d(1H) = 0.00; d(13C) = 0.0], CHCl3
[d(1H) = 7.26], CDCl3 [d(13C) = 77.0], acetone-d5 [d(1H) = 2.09],
acetone-d6 [d(13C) = 29.3], C6D6 [d(13C) = 128.0], and externally on
85% H3PO4 [d(31P) = 0.0]. Mass spectra were recorded on a Thermo
Finnigan MAT 95 mass spectrometer. IR spectra were recorded on
a Perkin-Elmer FT-IR spectrometer Spectrum 1000. Melting points
were determined using a Büchi B-540 melting point apparatus un-
der argon. Elemental analyses were performed at the microanalyti-
cal laboratory of the chemistry department of the LMU München.
At –78 °C, a solution of 1-lithionaphthalene [3.6 mmol, 0.93 equiv,
from 1-bromonaphthalene (745 mg, 3.6 mmol) and n-BuLi (3.8
mmol, 0.98 equiv)] in anhyd THF (10 mL) was added via syringe
over 1 min to the reaction mixture of the 9-anthrylphosphonite 1.
The reaction was stirred for an additional 10 min and then allowed
to slowly warm to r.t. The conversion may be checked by 31P NMR
spectroscopy (if necessary, more 1-lithionaphthalene can be added).
The mixture can either be used in situ for a third substitution reac-
tion or the phosphinite 2 can be isolated. For the isolation of phos-
phinite 2, the reaction mixture was quenched with H2O (1 mL), and
the THF solvent was removed in vacuo. Aqueous work-up with
Et2O, and stirring the oily product with hexane overnight at r.t., af-
forded a microcrystalline solid. Yellow microcrystalline powder,
crystallized from hexane; yield: 46%. Content of anthracene side
product can be minimized by Et2O filtration from solid anthracene.
Synthesis 2006, No. 2, 354–365 © Thieme Stuttgart · New York

362
J. Keller et al.
FEATURE ARTICLE
3
1H NMR (300.13 MHz, CDCl3): d = 7.00 (tt, JH,H = 7 Hz,
IR (KBr): 3044 (w), 2933 (w), 2833 (w), 1944 (w), 1812 (w), 1619
(w), 1582 (w), 1570 (w), 1547 (w), 1510 (w), 1470 (m), 1446 (w),
1429 (m), 1396 (w), 1296 (w), 1270 (w), 1243 (m), 1179 (w), 1161
(w), 1130 (w), 1070 (w), 1041 (w), 1021 (m), 955 (w), 919 (w), 887
(w), 842 (w), 818 (w), 782 (w), 753 (w), 732 (s), 668 (w), 610 (w),
576 (w), 557 (w), 542 (w), 530 (w), 495 (w), 467 cm–1 (w).
4JH,H = 1.5 Hz, 1 H, p-CH), 7.11–7.22 (m, 4 H), 7.30 (tpseudod,
4
3
3JH,H = 8 Hz, JH,H = 1.5 Hz, 1 H), 7.35 (tpseudod, JH,H = 8 Hz,
4JH,H = 1.5 Hz, 1 H), 7.41–7.46 (m, 6 H), 7.58 (ddd, JH,H = 7 Hz,
3
3JP,H = 5 Hz, 4JH,H = 1 Hz, 1 H, 2-CHnaphthyl), 7.81 (tpseudo, J = 9 Hz,
3
2 H, 7¢-CHnaphthyl), 8.00 (m, 2 H), 8.23 (d, JH,H = 8.4 Hz, 1 H, 8¢-
CHnaphthyl), 8.58 (s, 1 H, 10-CH), 9.18 (m, 2 H, 1,8-CH).
1H NMR (300.13 MHz, CDCl3): d = 3.40 (s, 3 H, OCH3), 6.67
13C{1H} NMR (75.48 MHz, CDCl3): d = 118.8 (d, JP,C = 11 Hz, o-
CH), 122.5 (s, p-CH), 125.2 (s), 125.7 (s), 125.9 (s), 126.5 (s), 126.7
(d, 3JP,C = 27 Hz, 1,8-CH), 127.2 (s), 128.9 (s), 129.3 (s), 129.5 (s),
129.6 (s), 129.6 (s), 130.0 (s), 130.1 (s), 131.5 (d, JP,C = 4 Hz), 132.4
(s), 133.7 (s), 133.8 (d, JP,C = 19 Hz), 135.6 (d, JP,C = 15 Hz), 136.0
(d, JP,C = 18 Hz), 157.5 (d, 2JP,C = 12 Hz, POCq).
(tpseudotpseudo,
3JH,H = 7 Hz, 4J = 1 Hz, 1 H, 5¢-CH), 6.75 (ddd,
4 4
3JH,H = 8 Hz, JP,H = 4 Hz, JH,H = 1 Hz, 1 H, 3¢-CH), 6.86 (ddd,
3
4
3JH,H = 8 Hz, JH,H = 6 Hz, JH,H = 1 Hz, 1 H, 4¢-CH), 7.14 (ddd,
3JH,H = 9 Hz, 3JH,H = 6.6 Hz, 4JH,H = 1 Hz, 4 H, 2,7-CH), 7.30 (m, 1
H, 6¢-CH), 7.34 (ddd, 3JH,H = 8.4 Hz, 3JH,H = 6.6 Hz, 4JH,H = 1 Hz, 4
3
4
H, 3,6-CH), 7.96 (dd, JH,H = 8.4 Hz, JH,H = 1 Hz, 4 H, 4,5-CH),
8.48 (s, 2 H, 10-CH), 8.78 (ddd, 3JH,H = 9 Hz, 4JP,H = 4 Hz, 4JH,H = 1
Hz, 4 H, 1,8-CH).
31P{1H} NMR (80.95 MHz, CDCl3): d = 108.4.
MS (EI): m/z (%) = 428.1 (83.81, [M+]), 335.1 (100, [(M – OPh)+]),
13C{1H} NMR (75.48 MHz, CDCl3): d = 55.3 (s, OCH3), 110.1 (s,
3¢-CH), 121.1 (s, 5¢-CH), 124.7 (s, 3,6-CH), 125.7 (d, JP,C = 4 Hz,
302.1 [(M – naphthyl)+].
1
3
2,7-CH), 126.1 (d, JP,C = 13 Hz, 1¢-CP), 127.2 (d, JP,C = 21 Hz,
9-Anthryl(1-naphthyl)phenylphosphine (‘3-2-1 Phosphine’)
(3); Typical Procedure
3
1,8-CH), 129.3 (s, 4,5-CH), 129.7 (s), 130.0 (d, JP,C = 26 Hz, 9-
CP), 130.3 (s), 131.5 (d, JP,C = 4 Hz), 132.7 (d, JP,C = 2 Hz), 135.5
A solution of PhLi (6 mmol, 1.5 equiv) in THF (10 mL) was added
via syringe at r.t. to the reaction mixture of the phosphinite 2. The
reaction was stirred for an additional hour. The mixture was
quenched with H2O (1 mL) and THF was removed in vacuo. Et2O
(50 mL) and H2O (50 mL) were added. The layers were separated
and the aqueous phase was extracted with Et2O (2 × 25 mL). The
combined organic extracts were washed with H2O, dried (Na2SO4)
and concentrated under reduced pressure to provide yellow solid.
The crude product was crystallized from acetone to afford the title
compound as a yellow solid. Yellow microcrystalline powder, re-
crystallized from acetone; isolated yield: 66%; mp 214–218 °C.
(d, JP,C = 14 Hz), 161.3 (d, 2JP,C = 19 Hz, 2¢-COMe).
31P{1H} NMR (80.95 MHz, CDCl3): d = –39.6.
MS (EI): m/z (%) = 492.2 (100, [M+]), 461.2 (9.29, [(M – OMe)+]),
384.2 (4.71, [(M – anisyl)+]), 283.1 (10.57, [(M – OMe – anthr-
yl)+]).
Tris-2-(4,4¢-di-tert-butylbiphenylyl)phosphine (5)
4,4¢-Di(tert-butyl)-2-iodo-1,1¢-biphenyl35 reacted with two equiv of
Li metal within 3 h in Et2O at r.t. THF should not be used as the sol-
vent. Then, only the deiodinated hydrocarbon can be isolated.
IR (KBr): 3049 (m), 1711 (w), 1619 (w), 1585 (w), 1511 (w), 1482
(w), 1434 (m), 1385 (w), 1322 (w), 1258 (w), 1140 (w), 1022 (w),
895 (w), 842 (w), 798 (m), 776 (m), 734 (s), 699 (w), 660 (w), 608
(w), 542 (w), 528 (w), 486 (w), 458 cm–1 (w).
Colorless crystals, recrystallized from acetone; isolated yield of an-
alytically pure material: 65%; mp 240 °C.
IR (KBr): 3055 (w), 3027 (w), 2963 (s), 2903 (m), 2867 (m), 2711
(w), 1902 (w), 1787 (w), 1612 (w), 1595 (w), 1513 (w), 1480 (m),
1393 (m), 1383 (w), 1362 (m), 1267 (m), 1202 (w), 1154 (w), 1120
(w), 1081 (w), 1025 (w), 1004 (w), 923 (w), 898 (w), 825 (s), 786
(w), 759 (w), 741 (w), 732 (w), 681 (w), 642 (w), 621 (w), 582 (m),
515 (w), 476 cm–1 (w).
1H NMR (399.94 MHz, CDCl3): d = 7.05–7.11 (m, 3 H, o,p-CH),
3
7.15–7.22 (m, 5 H), 7.26–7.40 (m, 5 H), 7.72 (d, JH,H = 8.2 Hz, 1
H), 7.77 (d, 3JH,H = 8.2 Hz, 1 H), 7.94 (dd, 3JH,H = 8.5 Hz, 4JH,H = 0.5
Hz, 2 H), 8.19 (ddd, 3JH,H = 8.5 Hz, 4JP,H = 3.6 Hz, 4JH,H = 0.8 Hz, 1
3
H, 8-CHnaphthyl), 8.53 (s, 1 H, 10-CH), 8.78 (ddd, JH,H = 9.0 Hz,
1H NMR (300.13 MHz, CDCl3): d = 1.18 [s, 27 H, C(CH3)3], 1.33
4JP,H = 4.8 Hz, 4JH,H = 0.8 Hz, 2 H, 1,8-CH).
3
[s, 27 H, C(CH3)3], 6.88 (dqpseudo, JH,H = 9 Hz, J = 2–3 Hz, 6 H,
13C{1H} NMR (100.57 MHz, CDCl3): d = 125.1 (s, CH), 125.6 (s,
CH), 125.9 (s, CH), 126.0 (s, CH), 126.2 (d, JP,C = 2 Hz, CH), 126.6
(d, 2JP,C = 23 Hz, 8-CHnaphthyl), 127.4 (s, p-CH), 128.1 (d, 3JP,C = 25
3
4
2¢,6¢-CH), 6.94 (dd, JP,H = 3 Hz, JH,H = 2 Hz, 3 H, 3-CH), 7.06–
7.14 (m, 9 H, 6-CH and 3¢,5¢-CH), 7.29 (dd, 3JH,H = 7.9 Hz, 4JH,H = 2
Hz, 3 H, 5-CH).
2
Hz, 1,8-CH), 128.3 (d, JP,C = 6 Hz, o-CH), 128.7 (d, JP,C = 2 Hz,
13C{1H} NMR (75.47 MHz, CDCl3): d = 31.2 [s, C(CH3)3], 31.4 [s,
C(CH3)3], 34.37 (s, CMe3), 34.45 (s, CMe3), 123.8 (s, 3¢,5¢-CH),
CH), 129.2 (s, CH), 129.3 (s, CH), 131.0 (s, CH), 131.9 (s, 10-CH),
132.0 (d, JP,C = 28 Hz, Cq), 132.3 (d, JP,C = 19 Hz, 2-CHnaphthyl),
132.8 (d, JP,C = 16 Hz, Cq), 133.5 (d, JP,C = 4 Hz, Cq), 135.3 (d,
JP,C = 24 Hz, Cq), 136.9 (d, JP,C = 14 Hz, Cq), 137.2 (d, JP,C = 12 Hz,
Cq), one quarternary carbon was not identified unambiguously.
3
4
124.6 (s, 6-CH), 128.8 (d, JP,C = 5 Hz, 3-CH), 129.4 (d, JP,C = 5
Hz, 2¢,6¢-CH), 132.2 (s, 6-CH), 136.7 (d, 3JP,C = 20 Hz, 1¢-C), 138.9
(d, 2JP,C = 6 Hz, 1-CH), 144.9 (d, 1JP,C = 30 Hz, PC), 148.7 (s, C–t-
Bu), 149.0 (s, C–t-Bu).
31P{1H} NMR (80.95 MHz, CDCl3): d = –28.4.
31P{1H} NMR (80.95 MHz, CDCl3): d = –27.3.
MS (EI): m/z (%) = 412.2 (100, [M+]), 334.1 (2.72, [(M – Ph)+]),
MS (EI): m/z (%) = 827.5 (12, [M+]), 825.5 (100, [(M – 2 H)+]),
283.1 (7.84, [(M – naphthyl)+]), 233.1 (7.27, [(M – anthryl)+]).
768.7 (10.73, [(M – t-Bu)+]).
Anal. Calcd for C30H21P: C, 87.36; H, 5.13. Found: C, 86.55; H,
5.10. Traces of Et2O could not be removed in vacuo even at
>150 °C.
Anal. Calcd for C60H75P: C, 87.12; H, 9.14. Anal. Calcd for
C60H75P·C3H6O: C, 85.47; H, 9.22. Found: C, 85.13; H, 9.38.
The procedures used to prepare the compounds listed below were
typical of the P(OPh)3-based syntheses and work-up of phospho-
nites, phosphinites and tertiary phosphines is described above in the
typical procedures for 1–3.
Diphenyl 2-(2¢,6¢-Dimethoxybiphenylyl)phosphonite (6)
Colorless crystals, recrystallized from acetone; isolated yield of an-
alytically pure material: 68%; mp 127 °C.
IR (KBr): 3049 (w), 3011 (w), 2962 (w), 2936 (w), 2837 (w), 2182
(w), 1922 (w), 1784 (w), 1596 (s), 1483 (s), 1472 (s), 1453 (m),
1430 (m), 1300 (w), 1282 (w), 1250 (s), 1223 (s), 1196 (s), 1172
(w), 1158 (m), 1128 (w), 1109 (s), 1073 (w), 1032 (w), 1022 (w),
1001 (w), 954 (w), 910 (w), 893 (w), 873 (m), 851 (s), 824 (w), 784
Di(9-anthryl)(2-methoxyphenyl)phosphine (4)
Yellow microcrystalline powder; isolated yield from two fractions:
65%; mp 306 °C (dec.).
Synthesis 2006, No. 2, 354–365 © Thieme Stuttgart · New York

FEATURE ARTICLE
Phosphine Syntheses
363
(m), 770 (s), 752 (w), 737 (m), 722 (m), 693 (m), 674 (w), 612 (w),
594 (w), 556 (w), 540 (w), 512 (w), 502 (w), 486 (w), 463 cm–1 (w).
1¢-C), 120.5 (s, 5¢¢-CH), 126.5 (d, 1JP,C = 14 Hz, 1¢¢-CP), 126.7 (s),
128.2 (s), 128.8 (s), 129.3 (s, 4¢¢-CH), 131.0 (d, 2JP,C = 6.4 Hz, 6¢¢-
CH), 134.1 (s), 134.5 (s), 137.1 (d, JP,C = 9 Hz), 141.1 (d, 1JP,C = 35
Hz, 2-CP), 157.8 (s, 2¢,6¢-COMe), 161.3 (d, JP,C = 16 Hz, 2¢¢-
COMe).
1H NMR (399.94 MHz, CDCl3): d = 3.65 (s, 6 H, 2 OCH3), 6.63 (d,
2
2 H, 3JH,H = 8.4 Hz, 3¢,5¢-CH), 6.84 (m, 4 H, o-CH), 7.00 (ttd, 2 H,
4
5
3JH,H = 7.4 Hz, JH,H = 1 Hz, JP,H = 0.5 Hz, p-CH), 7.18 (dd,
3JH,H = 8.4 Hz, 3JH,H = 8.4 Hz, 4 H, m-CH), 7.29 (dddd, 3JH,H = 7.6
Hz, 4JP,H = 4.4 Hz, 4JH,H = 1.4 Hz, 5JH,H = 0.4 Hz, 1 H, 6-CH), 7.34
31P{1H} NMR (80.95 MHz, CDCl3): d = –33.3.
MS (EI): m/z (%) = 427.2 (100, [(M – OMe)+]), 381.2 (4.75, [(M –
3
3
(t, JH,H = 8.4 Hz, 1 H, 4¢-CH), 7.48 (tpseudod, JH,H = 7.5 Hz,
OMe, – OMe, – Me)+]).
4JH,H = 1.4 Hz, 1 H, 4- or 5-CH), 7.56 (tpseudod, JH,H = 7.5 Hz,
3
4JH,H = 1.4 Hz, 1 H, 5- or 4-CH), 8.08 (dddd, JH,H = 7.7 Hz,
3
Anal. Calcd for C28H27O4P: C, 73.35; H, 5.94. Found: C, 72.94; H,
6.03.
3JP,H = 3.5 Hz, 4JH,H = 1.5 Hz, 5JH,H = 0.4 Hz, 1 H, 2-CH).
13C{1H} NMR (100.57 MHz, CDCl3): d = 55.7 (s, OCH3), 103.8 (s,
Dibutyl-2-(2¢,6¢-dimethoxybiphenylyl)phosphine (9)
Colorless crystals, recrystallized from Et2O; isolated yield of ana-
lytically pure material: 61% (one-step from phosphonite 6) or 19%
(two-step one-pot procedure); mp 100 °C.
3
3
3¢,5¢-CH), 117.1 (d, JP,C = 8 Hz, 1¢-C), 119.8 (d, JP,C = 9 Hz, o-
CH), 123.0 (s, p-CH), 127.3 (s, 4- or 5-CH), 128.9 (d, 2JP,C = 4.4 Hz,
3-CH), 129.2 (s, m-CH), 129.6 (s, 4¢-CH), 130.7 (s, 5- or 4-CH),
131.0 (d, 3JP,C = 5 Hz, 6-CH), 138.1 (d, 1JP,C = 38 Hz, 2-CP), 139.5
2
2
IR (KBr): 3044 (w), 3006 (w), 2956 (m), 2924 (m), 2870 (m), 2834
(s), 2183 (w), 1589 (s), 1557 (w), 1471 (s), 1427 (m), 1378 (w),
1305 (w), 1282 (w), 1244 (s), 1172 (w), 1109 (s), 1035 (w), 1004
(w), 949 (w), 895 (w), 779 (w), 765 (w), 742 (w), 726 (m), 705 (w),
598 (w), 544 (w), 498 (w), 460 cm–1 (w).
1H NMR (300.13 MHz, CDCl3): d = 0.82 (t, 6 H, 3JH,H = 7.0 Hz, 2
CH3), 1.24 (m, 8 H, 2 CH2CH2CH3), 1.42–1.66 (m, 4 H, 2 PCH2),
3.70 (s, 6 H, 2 OCH3), 6.54 (d, 3JH,H = 8.4 Hz, 2 H, 3¢,5¢-CH), 7.16
(m, 1 H, 6-CH), 7.32 (t, 3JH,H = 8.4 Hz, 1 H, 4¢-CH), 7.38 (m, 2 H,
4,5-CH), 7.57 (m, 1 H, 3-CH).
(d, JP,C = 17 Hz, 1-C), 155.5 (d, JP,C = 7.5 Hz, POC), 158.0 (s,
2¢,6¢-COMe).
31P{1H} NMR (80.95 MHz, CDCl3): d = 157.6.
MS (EI): m/z (%) = 430.2 (0.05, [M+]), 415.2 (0.07, [(M – Me)+]),
399.2 (100, [(M – OMe)+]).
Anal. Calcd for C26H23O4P: C, 72.55; H, 5.39. Found: C, 72.28; H,
5.49.
2-(2¢,6¢-Dimethoxybiphenylyl)diphenylphosphine (7)
Colorless crystals, recrystallized from acetone; isolated yield of an-
alytically pure material: 74%; mp 138 °C.
13C{1H} NMR (75.47 MHz, CDCl3): d = 13.8 (s, CH3), 24.5 (d,
2
3JP,C = 12 Hz, CMe), 28.2 (d, JP,C = 15 Hz, CCMe), 28.6 (d,
IR (KBr): 3048 (w), 3002 (w), 2964 (w), 2935 (w), 2834 (w), 1587
(m), 1467 (m), 1428 (m), 1299 (w), 1286 (w), 1247 (m), 1168 (w),
1106 (s), 1029 (w), 1000 (w), 920 (w), 782 (w), 760 (w), 745 (m),
734 (w), 699 (m), 664 (w), 594 (w), 544 (w), 515 (w), 506 (w), 491
(w), 465 cm–1 (w).
1H NMR (300.13 MHz, CDCl3): d = 3.43 (s, 6 H, OCH3), 6.51 (d,
3JH,H = 8.4 Hz, 2 H, 3¢,5¢-CH), 7.10–7.30 (m, 14 H), 7.40 (tpseudodd,
3JH,H = 7.4 Hz, 4JH,H = 1 Hz, 5JH,H = 0.4 Hz, 1 H).
1JP,C = 12 Hz, PCH2), 55.5 (s, OCH3), 103.4 (s, 3¢,5¢-CH), 119.6 (d,
3JP,C = 6 Hz, 1¢-C), 127.1 (s), 128.2 (s), 128.9 (s), 129.7 (s), 130.5
2
2
(d, JP,C = 6 Hz, 3-C), 139.4 (d, JP,C = 15 Hz, 1-C), 141.4 (d,
1JP,C = 31 Hz, 2-CP), 157.6 (s, COMe).
31P{1H} NMR (80.95 MHz, CDCl3): d = –33.5.
MS (EI): m/z (%) = 343.2 (16.21, [(M + H)+]), 327.2 (100, [(M –
Me)+]), 301.2 (4.75, [(M – OMe)+]).
Anal. Calcd for C22H31O2P: C, 73.72; H, 8.72. Found: C, 73.52; H,
8.81.
13C{1H} NMR (75.47 MHz, CDCl3): d = 55.3 (s, OCH3), 103.5 (s,
3¢,5¢-CH), 119.1 (d, 3JP,C = 8 Hz, 1¢-C), 127.2 (s), 127.9 (s, p-CH),
2
128.0 (d, JP,C = 7 Hz, m-CH), 128.7 (s), 129.1 (s), 130.9 (d,
Phenyl tert-Butyl-2-(2¢,6¢-dimethoxybiphenylyl)phosphinite
(10)
Colorless crystals, recrystallized from EtOH; isolated yield of ana-
2JP,C = 6 Hz, 3-CH), 133.6 (d, 2JP,C = 20 Hz, o-CH), 134.0 (s), 137.7
2
1
(d, JP,C = 10 Hz, 1-C), 138.2 (d, JP,C = 13 Hz, ipso-C), 141.4 (d,
1JP,C = 33.7 Hz, 2-CP), 157.8 (s, COMe).
lytically pure material: 26%; mp 123 °C.
31P{1H} NMR (80.95 MHz, CDCl3): d = –11.6.
IR (KBr): 3050 (w), 2996 (w), 2954 (m), 2939 (m), 2897 (w), 2862
(w), 2833 (w), 1595 (m), 1493 (m), 1471 (m), 1455 (m), 1430 (m),
1364 (w), 1301 (w), 1283 (w), 1246 (m), 1226 (m), 1165 (w), 1109
(s), 1072 (w), 1036 (w), 1000 (w), 896 (w), 866 (m), 829 (w), 810
(w), 783 (m), 766 (m), 746 (w), 721 (m), 692 (m), 668 (w), 613 (w),
598 (w), 540 (w), 504 (w), 474 (w), 462 cm–1 (w).
MS (EI): m/z (%) = 367.1 (100, [(M – OMe)+]), 352.1 (6.11, [(M –
OMe, – Me)+]).
Anal. Calcd for C26H23O2P: C, 78.38; H, 5.82. Found: C, 78.05; H,
5.86.
2-(2¢,6¢-Dimethoxybiphenylyl)bis(2-methoxyphenyl)phosphine
(8)
Colorless crystals, recrystallized from EtOH; isolated yield of ana-
1H NMR (599.80 MHz, CDCl3): d = 0.93 [d, 3JP,H = 12.7 Hz, 9 H,
C(CH3)3], 3.67 (s, 3 H, OCH3), 3.67 (s, 3 H, OCH3), 6.60 (d,
3JH,H = 8.4 Hz, 1 H, 3¢- or 5¢-CH), 6.60 (d, 3JH,H = 8.4 Hz, 1 H, 5¢- or
3¢-CH), 6.95 (tpseudo, 3JH,H = 7.3 Hz, 1 H, p-CH), 7.07 (d, 3JH,H = 8.4
Hz, 2 H, o-CH), 7.20 (m, 1 H, 6-CH), 7.22 (tpseudo, 3JH,H = 8.4 Hz, 2
lytically pure material: 26%; mp 199 °C.
IR (KBr): 3057 (w), 3005 (w), 2934 (w), 2834 (w), 1588 (m), 1572
(m), 1472 (s), 1430 (m), 1272 (m), 1244 (s), 1179 (w), 1162 (w),
1110 (s), 1072 (w), 1041 (w), 1025 (m), 1002 (w), 784 (w), 756 (m),
730 (w), 594 (w), 520 (w), 504 cm–1 (w).
3
H, m-CH), 7.31 (t, JH,H = 8.4 Hz, 1 H, 4¢-CH), 7.36 (tpseudod,
4
3JH,H = 7.6 Hz, JH,H = 1.2 Hz, 1 H, 4- or 5-CH), 7.43 (tpseudo
,
3JH,H = 7.4 Hz, 1 H, 5- or 4-CH), 7.78 (ddd, JH,H = 7.7 Hz,
3
3JP,H = 3.0 Hz, 4JH,H = 1.0 Hz, 1 H, 3-CH).
1H NMR (300.13 MHz, CDCl3): d = 3.42 (s, 6 H, OCH3), 3.60 (s, 6
2
13C{1H} NMR (150.83 MHz, CDCl3): d = 24.8 [d, JP,C = 17 Hz,
H, OCH3), 6.53 (d, 3JH,H = 8.4 Hz, 2 H, 3¢,5¢-CH), 6.76–6.88 (m, 6
1
C(CH3)3], 33.8 (d, JP,C = 14 Hz, CMe), 55.2 (s, OCH3), 55.4 (s,
3
4
H), 7.12 (dddd, JH,H = 7.6 Hz, JP,H = 3.8 Hz, JH,H = 1.5 Hz,
5JH,H = 0.5 Hz, 1 H), 7.18–7.31 (m, 5 H), 7.39 (tpseudodd, 3JH,H = 7.8
Hz, 4JH,H = 1.5 Hz, J = 0.6 Hz, 1 H).
OCH3), 103.5 (s, 3¢-CH or 5¢-CH), 103.5 (s, 5¢-CH or 3¢-CH), 118.1
3
3
(d, JP,C = 6 Hz, 1¢-C), 119.2 (d, JP,C = 9 Hz, o-CH), 121.6 (s, p-
CH), 126.3 (s), 129.0 (s), 129.0 (s, m-CH), 129.1 (s), 130.5 (s),
131.2 (d, 2JP,C = 5 Hz, 3-CH), 138.8 (d, 1JP,C = 32 Hz, 2-PC), 139.0
13C{1H} NMR (75.47 MHz, CDCl3): d = 55.1 (s, OCH3), 55.5 (s,
OCH3), 103.5 (s, 3¢,5¢-C), 110.1 (s, 3¢¢-CH), 119.2 (d, 3JP,C = 7 Hz,
Synthesis 2006, No. 2, 354–365 © Thieme Stuttgart · New York

364
J. Keller et al.
FEATURE ARTICLE
2
(d, JP,C = 29 Hz, 1-C), 156.9 (s, COMe), 158.2 (s, COMe), 158.3
(d, 2JP,C = 8 Hz, POC).
3¢¢,5¢¢-CH), 103.8 (s, 3¢- or 5¢-CH), 104.7 (s, 5¢- or 3¢-CH), 108.0 (d,
3
1JP,C = 34 Hz, 1¢¢-CP), 118.4 (d, JP,C = 5 Hz, 1¢-C), 119.4 (d,
3JP,C = 13 Hz, o-CH), 121.9 (s, p-CH), 126.2 (s), 127.5 (s), 129.8
(s), 129.9 (s, m-CH), 130.7 (d, JP,C = 5 Hz), 131.3 (d, JP,C = 3 Hz),
136.7 (d, 1JP,C = 30 Hz, 2-PC), 143.2 (d, JP,C = 17 Hz, 1-C), 158.3
(s, 2¢- or 6¢-COMe), 158.8 (s, 2¢- or 6¢-COMe), 159.5 (d, 2JP,C = 13
31P{1H} NMR (80.95 MHz, CDCl3): d = 128.2.
MS (EI): m/z (%) = 363.2 (100, [(M – OMe)+]), 307.2 (16.03, [(M
– OMe, – t-Bu)+]), 229.1 (36.23, [(M – OMe, – t-Bu, – Ph)+]).
2
Hz, POC), 165.2 (s, 4¢¢-COMe), 165.5 (d, JP,C = 12 Hz, 2¢¢,6¢¢-
Anal. Calcd for C24H27O3P: C, 73.08; H, 6.90. Found: C, 72.92; H,
6.95.
COMe).
31P{1H} NMR (80.95 MHz, CDCl3): d = 95.1.
Phenyl Cyclohexyl-2-(2¢,6¢-dimethoxybiphenylyl)phosphinite
(11)
MS (EI): m/z (%) = 505.3 (0.11, [(M + H)+]), 504.3 (0.05, [(M)+]),
489.2 (0.25, [(M – CH3)+]), 473.3 (100, [(M – OCH3)+]).
Colorless crystals; yield: <20% even with large excess Grignard re-
agent, magnesiate reagent,23 and long reaction times; mp 114 °C.
Anal. Calcd for C29H29O6P: C, 69.04; H, 5.79. Found: C, 68.68; H,
5.80.
IR (KBr): 3058 (w), 3015 (w), 2984 (w), 2902 (w), 2941 (m), 2818
(w), 1951 (w), 1630 (w), 1568 (w), 1458 (w), 1440 (w), 1422 (w),
1404 (w), 1277 (w), 1232 (w), 1203 (w), 1176 (w), 1150 (w), 1040
(s), 919 (w), 906 (m), 841 (w), 753 (w), 731 (w), 693 (w), 654 (w),
594 (w), 580 (w), 536 (w), 489 (w), 434 cm–1 (w).
1H NMR (599.80 MHz, CDCl3): d = 0.96–1.08 (m, 1 H), 1.08–1.22
(m, 3 H), 1.24–1.40 (m, 1 H), 1.50–1.68 (m, 4 H), 1.70–1.82 (m, 2
Butyl-2-(2¢,6¢-dimethoxybiphenylyl)(2,4,6-trimethoxyphen-
yl)phosphine (13)
Colorless crystals, recrystallized from EtOH; isolated yield of ana-
lytically pure material: 13%; mp 99 °C.
IR (KBr): 3047 (w), 2996 (w), 2954 (m), 2934 (m), 2870 (w), 2833
(m), 1590 (s), 1472 (s), 1430 (m), 1405 (m), 1328 (m), 1304 (w),
1283 (w), 1247 (m), 1222 (s), 1204 (m), 1157 (m), 1112 (s), 1088
(m), 1038 (w), 1002 (w), 951 (w), 919 (w), 896 (w), 814 (w), 781
(w), 758 (w), 744 (w), 723 (w), 670 (w), 638 (w), 594 (w), 543 (w),
506 (w), 467 cm–1 (w).
H), 3.65 (s, 3 H, OCH3), 3.69 (s, 3 H, OCH3), 6.61 (dpseudo
,
3
3JH,H = 8.4 Hz, 2 H, 3¢,5¢-CH), 6.93 (t, JH,H = 8 Hz, 1 H, p-CH),
7.02 (d, 3JH,H = 8 Hz, 2 H, o-CH), 7.17 (ddd, 3JH,H = 7 Hz, JP,H = 3
Hz, 4JH,H = 1 Hz, 1 H, 6-CH), 7.19 (tpseudo, 3JH,H = 8 Hz, 2 H, m-CH),
7.32 (tpseudo, 3JH,H = 8.4 Hz, 1 H, 4¢-CH), 7.39 (tpseudod, 3JH,H = 7 Hz,
4JH,H = 1 Hz, 1 H, 4- or 5-CH), 7.43 (tpseudod, 3JH,H = 7 Hz, 4JH,H = 1
Hz, 1 H, 5- or 4-CH), 7.77 (ddd, 3JH,H = 7 Hz, JP,H = 3 Hz, 4JH,H = 1
Hz, 1 H, 3-CH).
1H NMR (300.13 MHz, CDCl3): d = 0.85 (t, JH,H = 7 Hz, 3 H,
3
CH3), 1.10–1.50 (m, 4 H, CH2CH2CH3), 1.97–2.28 (m, 2 H, PCH2),
3.22 (s, 3 H, p-OCH3), 3.42 (s, 6 H, o-OCH3), 3.77 (s, 3 H, 2¢-
4
OCH3), 3.78 (s, 3 H, 6¢-OCH3), 5.88 (d, JP,H = 2 Hz, 2 H, 3¢¢,5¢¢-
13C{1H} NMR (150.83 MHz, CDCl3): d = 26.4 (s, CH2), 26.6 (d,
JP,C = 19 Hz, CH2), 26.8 (d, JP,C = 8 Hz, CH2), 27.0 (s, CH2), 27.1
(d, JP,C = 6 Hz, CH2), 42.5 (d, 1JP,C = 13 Hz, PCH), 55.3 (s, OCH3),
55.6 (s, OCH3), 103.3 (s, 3¢- or 5¢-CH), 103.7 (s, 5¢- or 3¢-CH), 117.8
CH), 6.24 (d, 3JH,H = 8.3 Hz, 1 H, 3¢- or 5¢-CH), 6.59 (d, 3JH,H = 8.3
Hz, 1 H, 5¢- or 3¢-CH), 6.98 (m, 1 H, 6-CH), 7.17 (tpseudo, 3JH,H = 8.3
3
Hz, 1 H, 4¢-CH), 7.21–7.34 (m, 2 H, 4,5-CH), 7.60 (dm, JH,H = 7
Hz, 1 H, 3-CH).
3
(d, JP,C = 6 Hz, 1¢-C), 118.9 (d, JP,C = 10 Hz, o-CH), 121.6 (s, p-
CH), 127.0 (s), 128.9 (s), 129.0 (s, m-CH), 129.2 (s), 129.3 (s),
13C{1H} NMR (75.47 MHz, CDCl3): d = 13.8 (s, CH3), 24.0 (d,
3
130.7 (d, 2JP,C = 4 Hz, 3-CH), 138.2 (d, 1JP,C = 32 Hz, 2-CP), 140.4
1JP,C = 10 Hz, PCH2), 24.7 (d, JP,C = 14 Hz, CH2CH3), 28.5 (d,
2
(d, JP,C = 27 Hz, 1-C), 157.2 (s, COMe), 158.2 (s, COMe), 158.4
2JP,C = 20 Hz, PCH2CH2), 54.8 (s, p-OCH3), 55.1 (s, 2¢-OCH3 or 6¢-
OCH3), 55.3 (s, 2 o-OCH3), 56.0 (s, 6¢-OCH3 or 2¢-OCH3), 90.6 (s,
3¢¢,5¢¢-CH), 102.7 (s, 3¢- or 5¢-CH), 103.9 (s, 5¢- or 3¢-CH), 105.3 (d,
1JP,C = 23 Hz, 1¢¢-CP), 119.4 (d, 3JP,C = 3 Hz, 1¢-C), 126.1 (s), 126.3
(d, 2JP,C = 9 Hz, POC).
31P{1H} NMR (80.95 MHz, CDCl3): d = 123.3.
MS (EI): m/z = 419.2 (0.1, [(M – H)+]), 405.2 (0.1, [(M – Me)+]),
1
(s), 128.2 (s), 130.3 (s), 138.5 (d, JP,C = 25 Hz, PC), 141.3 (d,
389.2 (100, [(M – OMe)+]).
2JP,C = 15 Hz), 157.6 (s, 2¢- or 6¢-COMe), 157.7 (s, 6¢- or 2¢-COMe),
162.3 (s, 4¢¢-COMe), 164.7 (d, 2JP,C = 8 Hz, 2¢¢,6¢¢-COMe).
Anal. Calcd for C26H29O3P C, 74.27; H, 6.95. Found: C, 73.71; H,
6.89.
31P{1H} NMR (80.95 MHz, CDCl3): d = –41.4.
MS (EI): m/z (%) = 467.3 (0.14, [(M – H)+]), 437.2 (100, [(M –
Phenyl 2-(2¢,6¢-Dimethoxybiphenylyl)(2,4,6-trimethoxyphen-
yl)phosphinite (12)
OMe)+]), 393.2 (1.72, [(M – OMe, – OMe, – Me)+]).
Colorless crystals, recrystallized from EtOH; isolated yield of ana-
lytically pure material: 58%; mp 150 °C.
Anal. Calcd for C27H33O5P: C, 69.22; H, 7.10. Found: C, 68.99; H,
7.11.
IR (KBr): 3049 (w), 3001 (w), 2936 (w), 2834 (w), 1592 (s), 1492
(m), 1472 (s), 1430 (m), 1406 (m), 1333 (m), 1285 (w), 1250 (m),
1223 (s), 1205 (m), 1157 (m), 1112 (s), 1089 (m), 1037 (w), 1000
(w), 951 (w), 920 (w), 861 (m), 813 (w), 782 (w), 761 (m), 729 (w),
692 (w), 672 (w), 640 (w), 611 (w), 594 (w), 565 (w), 504 (w), 463
cm–1 (w).
[N-(3¢5¢-Dimethylphenyl)pyrrol-2-yl]di(9-phenanthryl)phos-
phine (14)
Colorless crystals; isolated yield: 35%; mp 237 °C.
IR (KBr): 3055 (m), 2919 (m), 1953 (w), 1709 (w), 1611 (m), 1597
(m), 1511 (w), 1489 (m), 1473 (m), 1448 (m), 1367 (w), 1339 (w),
1290 (w), 1245 (w), 1232 (w), 1201 (w), 1166 (w), 1144 (w), 1128
(w), 1097 (w), 1060 (w), 1038 (w), 1003 (w), 973 (w), 951 (w), 899
(w), 850 (m), 816 (w), 787 (w), 763 (w), 747 (s), 723 (s), 696 (w),
650 (w), 616 (m), 560 (w), 488 (w), 476 (w), 465 cm–1 (w).
1H NMR (300.13 MHz, acetone-d6): d = 3.14 (s, 3 H, p-OCH3), 3.37
(s, 6 H, o-OCH3), 3.72 (s, 3 H, 2¢- or 6¢-OCH3), 3.77 (s, 3 H, 6¢- or
4
2¢-OCH3), 5.94 (d, JP,H = 2.3 Hz, 2 H, 3¢¢,5¢¢-CH), 6.26 (dd,
4
3JH,H = 8.4 Hz, JH,H = 0.6 Hz, 1 H, 3¢- or 5¢-CH), 6.62 (dd,
3JH,H = 8.4 Hz, 4JH,H = 0.6 Hz, 1 H, 5¢- or 3¢-CH), 6.86–6.93 (m, 2
1H NMR (399.92 MHz, CDCl3): d = 2.10 (s, 6 H, CH3), 6.19 (dd,
J = 3.5 Hz, J = 1.6 Hz, 1 H, CHpyrrolyl), 6.30 (t, J = 3.2 Hz, 1 H,
CHpyrrolyl), 6.84 (s, 1 H, p-CH), 6.97 (s, 2 H, o-CH), 7.20 (dd,
J = 5, 3 Hz, 1 H, 5-CHpyrrolyl), 7.49 (tpseudo, 3JH,H = 7 Hz, 2 H), 7.52
(tpseudo, 3JH,H = 7 Hz, 2 H), 7.61–7.68 (m, 8 H), 8.44 (dd, 3JH,H = 8.0
H), 7.02–7.09 (dm, 3JH,H = 8 Hz, 2 H, o-CH), 7.20 (t, 3JH,H = 8.4 Hz,
3
1 H, 4¢-CH), 7.15–7.28 (m, 3 H), 7.33 (tpseudodd, JH,H = 7.5 Hz,
3
3
J = 1.3 Hz, J = 1 Hz, 1 H). 7.95 (dddd, JH,H = 7.7 Hz, JP,H = 3.3
Hz, 4JH,H = 1.4 Hz, 5JH,H = 0.4 Hz, 1 H, 3-CH).
3
Hz, 4JP,H = 5.1 Hz, 2 H, 8-CH), 8.70 (d, JH,H = 8.3 Hz, 2 H), 8.74
13C{1H} NMR (75.48 MHz, acetone-d6): d = 55.1 (s, OCH3), 55.7
(d, 3JH,H = 8.3 Hz, 2 H).
4
(s, OCH3), 55.8 (s, OCH3), 56.1 (d, JP,C = 2 Hz, OCH3), 91.4 (s,
Synthesis 2006, No. 2, 354–365 © Thieme Stuttgart · New York

FEATURE ARTICLE
Phosphine Syntheses
365
13C{1H} NMR (100.57 MHz, CDCl3): d = 21.1 (s, CH3), 110.1 (s,
1989, 26, 7. (j) Luetkens, M. L. Jr.; Sattelberger, A. P.;
CHpyrrolyl), 122.0 (s, CHpyrrolyl), 122.5 (s, CH), 122.8 (s, CH), 123.7
Murray, H. H.; Basil, J. D.; Fackler, J. P. Jr. Inorg. Synth.
1990, 28, 305. (k) Trithienylphosphine derivative: Ishii, A.;
Takaki, I.; Nakayama, J.; Hoshino, M. Tetrahedron Lett.
1993, 34, 8255. (l) Tris(4-anilino)phosphine: Mizwicki, M.
T.; Haddadian, F.; Kimmerling, T. S.; Muehl, B. S.; Sheu,
B.-J.; Storhoff, B. N.; Huffman, J. C. Organometallics 2001,
20, 963. (m) d15-PPh3: Wang, Q.; Dereda, D.; Huynh, C.;
Schlosser, M. Chem. Eur. J. 2003, 9, 570. (n) PMe3:
Kornath, A.; Neumann, F.; Oberhammer, H. Inorg. Chem.
2003, 42, 2894. (o) P(C2H3)3: Monkowius, U.; Nogai, S.;
Schmidbaur, H. Organometallics 2003, 22, 145.
(13) Maienza, F.; Spindler, F.; Thommen, M.; Pugin, B.; Malan,
C.; Mezzeti, A. J. Org. Chem. 2002, 67, 5239.
3
(d, JP,C = 4 Hz, CH), 126.5 (d, JP,C = 9 Hz, 5-CHpyrrolyl), 126.5 (s,
2
CH), 126.6 (s, CH), 127.1 (d, JP,C = 0.6 Hz, CH), 127.2 (s, CH),
127.3 (d, 3JP,C = 28 Hz, 8-CH), 128.9 (s, CH), 129.0 (s, CH), 129.9
(s, Cq), 130.3 (d, JP,C = 5 Hz, Cq), 130.9 (s, Cq), 131.6 (d, JP,C = 2 Hz,
Cq), 132.7 (d, JP,C = 8 Hz, Cq), 133.4 (d, JP,C = 23 Hz, Cq), 134.9 (s,
CH), 138.5 (s, CarylMe), 140.4 (s, CarylN).
31P{1H} NMR (80.95 MHz, CDCl3): d = –44.1.
MS (EI): m/z (%) = 555.2 (100, [M+]), 378.2 (4.09, [(M – phen)+]),
201.1 (3.83, [(M – 2 phen)+]).
Anal. Calcd for C40H30NP: C, 86.46; H, 5.44; N, 2.52. Found: C,
85.57; H, 5.35; N, 2.45.
(14) Sander, M. Chem. Ber. 1962, 95, 473.
(15) Durán, E.; Velasco, D.; López-Calahorra, F. J. Chem. Soc.,
Acknowledgment
Perkin Trans. 1 2000, 591.
(16) Emrich, R.; Jolly, P. W. Synthesis 1993, 39.
(17) Guillaneux, D.; Martiny, L.; Kagan, H. B. Coll. Czech.
Chem. Commun. 2000, 65, 717.
(18) Farugia, L. J. J. Appl. Cryst. 1997, 30, 565.
(19) (a) Tolman, C. A. Chem. Rev. 1977, 77, 313. (b) Brown, T.
L. Inorg. Chem. 1992, 31, 1286.
(20) (a) Sasaki, S.; Sutoh, K.; Murakami, F.; Yoshifuji, M. J. Am.
Chem. Soc. 2002, 124, 14830. (b) Boeré, R. T.; Zhang, Y. J.
Organomet. Chem. 2005, 690, 2651.
This research was supported by the Deutsche Forschungsgemein-
schaft (DFG-Sachbeihilfe STR 861/2-1). Generous support by Prof.
Dr. Herbert Mayr is gratefully acknowledged.
References
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