Synthesis and Characterization of (Disilylanilino)Phosphines

Article abstract of DOI:10.1080/10426507.2015.1072196

(Graphical Abstract) The disilyl(4-bromo)aniline (Me₃Si)₂NC₆H₄Br (A) readily undergoes metal-halogen exchange to give the reactive organolithium derivative (Me₃Si)₂NC₆H₄

Full text of DOI:10.1080/10426507.2015.1072196

Phosphorus, Sulfur, and Silicon and the Related Elements
ISSN: 1042-6507 (Print) 1563-5325 (Online) Journal homepage: http://www.tandfonline.com:80/loi/gpss20
Synthesis and Characterization of
(Disilylanilino)Phosphines
Pradeep Devulapalli, Bin Wang & Robert H. Neilson
To cite this article: Pradeep Devulapalli, Bin Wang & Robert H. Neilson (2015) Synthesis and
Characterization of (Disilylanilino)Phosphines, Phosphorus, Sulfur, and Silicon and the Related
Elements, 190:12, 2154-2163, DOI: 10.1080/10426507.2015.1072196
To link to this article: http://dx.doi.org/10.1080/10426507.2015.1072196
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Date: 23 December 2015, At: 10:24

Phosphorus, Sulfur, and Silicon, 190:2154–2163, 2015
Copyright ꢀC Taylor & Francis Group, LLC
ISSN: 1042-6507 print / 1563-5325 online
DOI: 10.1080/10426507.2015.1072196
SYNTHESIS AND CHARACTERIZATION OF
(DISILYLANILINO)PHOSPHINES
Pradeep Devulapalli, Bin Wang,
and Robert H. Neilson
Department of Chemistry, Texas Christian University, Fort Worth, TX 76134, USA
GRAPHICAL ABSTRACT
The disilyl(4-bromo)aniline (Me3Si)2NC6H4Br (A) readily undergoes metal-halogen exchange
to give the reactive organolithium derivative (Me3Si)2NC6H4Li (B). Subsequent reactions with
various chlorophosphines, R(Rꢁ)PCl, or chloro(disilylamino)phosphines, (Me3Si)2NP(R)Cl,
were used to prepare three varieties of the title compounds: (Me3Si)2NC6H4P(Rꢁ)R (1: R = Rꢁ
= NMe2; 2: R = Rꢁ = OCH2CF3; 3: R = Ph, Rꢁ = OCH2CF3; 4: R = Rꢁ = Ph; 5: R = Ph, Rꢁ =
Me), (Me3Si)2NC6H4P(R)N(SiMe3)2 [6: R = Me; 7: R = i-Pr; 8: R = n-Bu, 9: R = OCH2CF3;
10: R = C6H4N(SiMe3)2; 11: R = Ph], and (Me3Si)2NC6H4P(Ph)R [12: R = n-Bu; 13: R =
C6H4N(SiMe3)2]. The new compounds 1–13 were generally obtained as colorless, distillable
liquids that were fully characterized by NMR (1H, 13C, and 31P) spectroscopy and elemental
analysis.
Keywords Silylaniline; anilinophosphine; phosphine; aminophosphine; silylamine
INTRODUCTION
The derivative chemistry of silicon-nitrogen-phosphorus compounds is quite ex-
tensive and, in many cases, synthetically useful.1 A wide variety of oxidation and sub-
stitution reactions at phosphorus combined with facile Si-N bond cleavage often leads to
Received 17 June 2015; accepted 29 June 2015.
Dedicated to Professor Robert R. Holmes in honor of his many years of professionalism and high standards
as Editor of this journal.
Address correspondence to Dr. Robert H Neilson, Department of Chemistry, Texas Christian University,
TCU Box 298860, Fort Worth, TX 76129, United States. E-mail: r.neilson@tcu.edu
2154

(DISILYLANILINO)PHOSPHINES
2155
intermolecular silyl group rearrangements2 or elimination of small-molecule silane byprod-
ucts.3 In particular, N-silylphosphoranimines, Me3SiN=P(Rꢁ)(R)X, readily undergo ther-
mally or catalytically induced elimination of Me3SiX to afford either cyclic4 or polymeric5
phosphazenes, (N=PRRꢁ)n, depending on the nature of the leaving group (X) and/or catalytic
factors.
More recently, we have extended our studies of Si-N-P compounds to include systems
in which the silicon-nitrogen and phosphorus-containing groups are not directly connected.
In this context, we report here on the synthesis and characterization of a series of new (dis-
ilylanilino)phosphines, (Me3Si)2N-C6H4-P(Rꢁ)R.6 Pending future studies, some of these
compounds are viewed as potential precursors to novel macrocyclic or polymeric organic-
inorganic hybrid materials, [-C6H4-N P(Rꢁ)R-]n.
RESULTS AND DISCUSSION
All of the synthetic chemistry reported here begins with deprotonation reactions of
4-bromoaniline (Equation (1)). Addition of one or two equivalents of n-BuLi readily affords
the corresponding N-lithio reagents in solution. In a slight modification of the published
procedure,7 the dilithio (-NLi2) intermediate was converted to the disilylaniline reagent A
in good yield. While the -NLi2 reagent reacted rapidly at 0◦C with the first equivalent of
Me3SiCl, addition of the second required refluxing for several hours in hexane. Subsequent
metal-halogen exchange (at 0◦C in Et2O solution) was used to generate the N-silylated
aryllithium reagent B.
(1)
The new (disilylanilino)phosphines described here were obtained from the aryllithium
reagent B by way of nucleophilic substitution reactions with three different types of P-Cl
compounds. In the first variation, treatment of mono-chlorophosphines RRꢁPCl with reagent
B at −78◦C in Et2O resulted in the formation of (disilylanilino)phosphines 1–5 (Equation
(2)). These compounds were obtained in moderate yields (ca. 60%) as colorless, distillable
liquids (1–3, 5) or a pale yellow solid (4) that were fully characterized by NMR (1H, 13C,
and 31P) spectroscopy and elemental analysis (see Experimental section).

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P. DEVULAPALLI ET AL.
(2)
Although these new phosphines 1–5 were readily prepared, this synthetic pathway is
limited by difficulties in obtaining many of the necessary mono-chlorophosphines. Other
than Ph2PCl (used to prepare 4), few such reagents are commercially available. The other
chlorophosphines (C–F) were prepared in this work as summarized in Equations (3)–(6).
(3)
(4)
(5)
(6)
While the dehydrohalogenation reaction of PCl3 with Me2NH (Equation (3)) was
a relatively straightforward, published procedure,8 those involving the P-trifluoroethoxy
analogs D (Equation (4)) and E (Equation (5)) were more complicated.9 Mixtures of prod-
ucts, such as D combined with smaller amounts of (CF3CH2O)3P and CF3CH2OPCl2, were
generally obtained due to multiple P-Cl replacements and/or disproportionation reactions
of the mixed-substituent products.9 Nonetheless, the impure reagents D and E were used
successfully to prepare the corresponding anilinophosphines 2 and 3 (Equation (2)).

(DISILYLANILINO)PHOSPHINES
2157
The alkyl/aryl(chloro)phosphine10 (F) was prepared in this study by treatment of
a (disilylamino)phosphine, (Me3Si)2NP(Ph)Me, with four equivalents of anhydrous HCl
(Equation (6)). Although the yield of F was relatively low (ca. 40%), this new method
holds promise for the preparation of other mixed-substituent chlorophosphines since the
requisite (silylamino)-phosphines are readily available from a “one-pot” procedure known
as the Wilburn11 method. In this process, either PCl3 or PhPCl2 is treated first with one
equivalent of (Me3Si)2NLi and the remaining P-Cl groups are then replaced by addition of
Grignard or organolithium reagents.
Our second synthetic approach to the title compounds generally made use of the
Wilburn11 method as summarized in Scheme 1. In this “one-pot” procedure, the dichloro-
phosphine intermediate, (Me3Si)2NPCl2, was treated first with organolithium reagent B,
followed by the appropriate Grignard or lithium reagent to afford compounds 6–10. Al-
ternatively, by starting with PhPCl2 instead of PCl3, the P-phenyl derivative 11 was easily
prepared. Notably, all of these new phosphines (6–11) contain both disilylanilino and disi-
lylamino groups on phosphorus (10 actually incorporates two of the anilino groups). They
were all obtained in moderate yields (ca. 50–60%) as colorless, distillable liquids that were
fully characterized by NMR (1H, 13C, and 31P) spectroscopy and elemental analysis.
Scheme 1
As is the case for all of the products reported here, the NMR spectral data for
compounds 6–11 are completely consistent with the proposed structures. For example, the
1,4-substitution pattern of aryl ring is clearly indicated by the observation of four distinct

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P. DEVULAPALLI ET AL.
signals in the 13C NMR spectra with three of the signals being doublets due to coupling
to phosphorus. The 31P chemical shifts generally reflect the expected electronic and steric
effects of the substituents at the 3-coordinate phosphorus center.12 It seems noteworthy
that, in all cases, the 31P chemical shifts are within 1 ppm of those observed for analogous
structures containing a simple P-phenyl group instead of the P-C6H4N(SiMe3)2 substituent.
In the third synthetic route to the title compounds, PhPCl2 was employed as a conve-
nient starting material (Scheme 2). In one case, it was treated first with the organolithium
reagent B and then with n-BuLi to yield the mixed-substituent phosphine 12. Similarly,
the direct reaction of PhPCl2 with two equivalents of B afforded 13 that contains two sily-
lanilino groups, similar to compound 10 (Scheme 1). Compounds 12 and 13 were obtained
as colorless, distillable liquids, and were characterized as previously described.
Scheme 2
In summary, this work demonstrates that a significant series (i.e., 1–13) of the title
compounds are accessible by varied synthetic routes. Studies of the derivative chemistry of
selected members of this series are ongoing and will be reported in due course.
EXPERIMENTAL SECTION
Materials and General Procedures
The following reagents were obtained from commercial sources and used without fur-
ther purification: BrC6H4NH2, (Me3Si)2NH, Me3SiCl, PCl3, PhPCl2, Ph2PCl, CF3CH2OH,
Me2NH, Et2NPh, CH3MgBr (3.0 M in ether), i-PrMgBr (2.0 M in ether), n-BuLi (2.5 M in
hexane), and anhydrous HCl (1.0 M in Et2O). The disilylaniline reagent (Me3Si)2NC6H4Br
(A7) and the chlorophosphines RRꢁPCl (C8: R = Rꢁ = NMe2; D9: R = Rꢁ = OCH2CF3; E9:
R = Ph, Rꢁ = OCH2CF3) were prepared by the referenced procedures, in some cases with
modifications as detailed below. The chlorophosphine, Ph(Me)PCl (F10), was prepared by
the reaction of the (disilylamino)phosphine (Me3Si)2NP(Me)Ph11 with dry HCl as described
below. Hexane and Et2O were distilled under N2 from CaH2 and either used immediately
1
1
or stored over molecular sieves. Proton, 13C{ H}, and 31P{ H} NMR spectra were obtained
on a Varian XL-300 spectrometer using CDC13 or C6D6 as a lock solvent. Positive 1H and

(DISILYLANILINO)PHOSPHINES
2159
13C NMR chemical shifts and 31P NMR shifts are downfield from the external references
Me4Si and H3PO4, respectively, with coupling constants (J) given in Hz. Elemental anal-
yses were performed by Schwarzkopf Microanalytical Laboratory, Woodside, NY or E&R
Microanalytical Laboratory, Corona, NY. All reactions and manipulations were carried out
under a nitrogen atmosphere and/or by using standard vacuum line techniques.
Preparation of the Disilylaniline, (Me3Si)2NC6H4Br (A)
A three-neck (2000 mL) round-bottom flask, equipped with a mechanical stirrer, N2
inlet, and an addition funnel was charged with Et2O (800 mL) and BrC6H4NH2 (51.6 g,
300 mmol). The mixture was cooled to 0◦C and n-BuLi (240 mL, 600 mmol) was added
slowly from the addition funnel. The mixture was allowed to warm to room temperature
and stirred for 1 h. The solution was cooled again to 0◦C and Me3SiCl (32.6 g, 300 mmol)
was added slowly. The mixture was then allowed to warm to room temperature and was
stirred for 2 h. Most of the Et2O was then removed under reduced pressure and hexane
(800 mL) was added, followed by additional Me3SiCl (39.0 g, 350 mmol). The mixture was
then refluxed while stirring overnight to complete the reaction. The salt was removed by
filtration and hexane was removed under reduced pressure. Fractional distillation afforded
compound A7 as a colorless liquid, bp: 57–59◦C (0.01 mm Hg), generally in 65–70% yield.
Preparation of the Chlorophosphine, (CF3CH2O)2PCl (D)
In a typical experiment, a three-neck (3000 mL) round-bottom flask, equipped with a
mechanical stirrer, N2 inlet, and an addition funnel was charged with Et2O (1500 mL) and
PCl3 (67.3 g, 490 mmol). The solution was cooled to 0◦C and a mixture of Et2NPh (147.7 g,
990 mmol) and CF3CH2OH (99.0 g, 990 mmol) was added from the addition funnel. The
mixture was then allowed to warm to room temperature and was stirred for 3 h. Ether was
removed under reduced pressure and the remaining volatile material was removed by distil-
lation at ca. 70◦C (5 mm Hg). By NMR spectroscopy, the distillate was determined to be a
mixture consisting of D9 (31P NMR: δ 166.0), (CF3CH2O)3P, and CF3CH2OPCl2. Repeated
distillations increased the relative proportion of C to ca. 60–70%. The mixture containing
C was subsequently used to prepare the (disilylanilino)phosphine 2. In a similar procedure,
the reaction of PhPCl2 and CF3CH2OH (mixed with Et2NPh) afforded the chlorophosphine
E, Ph(CF3CH2O)PCl (31P NMR: δ 177.5), containing ca. 10–20% of PhP(OCH2CF3)2.
This product mixture was then used to prepare the (disilylanilino)phosphine 3.
Preparation of the Chlorophosphine, Ph(Me)PCl (F)
A three-neck (1000 mL) round-bottom flask, equipped with a mechanical stirrer, N2
inlet, and an addition funnel was charged with Et2O (200 mL) and (Me3Si)2NP(Ph)Me11
(14.2 g, 50.0 mmol). The mixture was cooled to 0◦C and HCl (200 mL, 200 mmol, 1.0 M in
Et2O) was added slowly. The mixture was allowed to warm to room temperature and was
stirred for ca. 4 h. Most of the ether was removed under reduced pressure and hexane (ca.
200 mL) was added to precipitate the salt. The salt was removed by filtration and hexane
was removed under reduced pressure. Fractional distillation afforded the chlorophosphine
F10 (31P NMR: δ 87.0) as a colorless, very moisture-sensitive liquid, bp: 38–42◦C (0.01 mm
Hg), typically in ca. 40% yield.

2160
P. DEVULAPALLI ET AL.
Preparation of (Disilylanilino)phosphines, (M3Si)2NC6H4P(Rꢀ)R (1–5)
A typical experiment for the synthesis of 1 (R = Rꢁ = NMe2) is described here. A
three-neck (100 mL) round-bottom flask, equipped with a magnetic stirring bar, N2 inlet,
rubber septum, and an addition funnel was charged with Et2O (50 mL) and the disilylaniline
A (15.8 g, 50.0 mmol). The mixture was cooled to 0◦C and n-BuLi (20 mL, 50 mmol) was
added slowly via syringe. The mixture was allowed to warm to room temperature and was
stirred for 1 h, affording a solution of the organolithium reagent B. Separately, another three-
neck (250 mL) round-bottom flask, equipped with a magnetic stirring bar, N2 inlet, rubber
septum, and an addition funnel was charged with Et2O (50 mL) and the chlorophosphine,
(Me2N)2PCl (7.70 g, 50.0 mmol). The solution of B, prepared above, was transferred via
cannula to the addition funnel and added slowly to the solution of (Me2N)2PCl with stirring
at −78◦C. The mixture was allowed to warm to room temperature and was stirred for ca.
2 h. Most of the ether was removed under reduced pressure and hexane (ca. 100 mL) was
added to precipitate the salt. The salt was removed by filtration and hexane was removed
under reduced pressure. Fractional distillation afforded 1 as a colorless liquid. (1: R = Rꢁ
= NMe2) Yield: 63%. bp: 87–90◦C (0.01 mm Hg). 31P NMR: δ 100.8. 1H NMR: δ 0.05 (s,
Me3SiN), 2.74 (d, Me2N, JPH = 9.1), 6.9–7.2 (m, C6H4). 13C NMR: δ 2.1 (s, Me3SiN), 41.6
(d, Me2N, JPC = 15.2), 134.9 (d, PC6H4, C1, JPC = 6.8), 129.9 (d, PC6H4, C2,6, JPC = 4.1),
131.3 (d, PC6H4, C3,5, JPC = 4.1), 147.5 (s, PC6H4, C4). Anal. Calcd. for C16H34N3PSi2:
C, 54.04; H, 9.64. Found: C, 53.91; H, 10.22.
The (disilylanilino)phosphines 2 and 3 were prepared in the same manner from
the corresponding chloro(trifluoroethoxy)phosphine reagents C and D, respectively. Both
were initially obtained by fractional distillation as colorless liquids containing ca. 3–5%
impurities as indicated by NMR spectroscopy. Redistillation afforded the pure compounds
that were characterized as follows. (2: R = Rꢁ = OCH2CF3). Yield: ca. 60%. bp: 61–61◦C
(0.01 mm Hg). 31P NMR: δ 168.4. 1H NMR: δ 0.07 (s, Me3SiN), 3.9–4.2 (m, OCH2CF3),
6.9–7.2 (m, C6H4). 13C NMR: δ 2.0 (s, Me3SiN), 63.5 (dq, OCH2CF3, JPC = 8.7, JFC
=
36.2), 123.5 (dq, JPC = 6.2, JFC = 277.8), 131.8 (d, PC6H4, C1, JPC = 18.5), 130.3 (d,
PC6H4, C2,6, JPC = 6.2), 130.1 (d, PC6H4, C3,5, JPC = 21.8), 152.0 (s, PC6H4, C4). Anal.
Calcd. for C16H26F6O2NPSi2: C, 41.28; H, 5.63. Found: C, 41.73; H, 6.13. (3: R = Ph,
Rꢁ = OCH2CF3). Yield: ca. 60%. bp: 121–123◦C (0.01 mm Hg). 31P NMR: δ 128.3. 1H
NMR: δ 0.06 (s, Me3SiN), 4.0–4.2 (m, OCH2CF3), 7.0–7.5 (m, C6H4), 7.3–7.4 (m, Ph).
13C NMR: δ 2.1 (s, Me3SiN), 66.9 (dq, OCH2CF3, JPC = 21.2, JFC = 35.2), 123.7 (dq, JPC
= 9.3, JFC = 278.8), 134.4 (d, PC6H4, C1, JPC = 16.1), 128.4 (d, PC6H4, C2,6, JPC = 6.9),
130.4 (d, PC6H4, C3,5, JPC = 21.2), 150.6 (s, PC6H4, C4), 140.6 (d, PPh, C1, JPC = 16.3),
130.1 (d, PPh, C2,6, JPC = 7.5), 131.5 (d, PPh, C3,5, JPC = 23.2), 129.6 (s, PPh, C4). Anal.
Calcd. for C20H29F3ONPSi2: C, 54.15; H, 6.59. Found: C, 53.98; H, 6.47.
Similarly, the reaction of B with Ph2PCl afforded (disilylanilino)phosphine 4 as a
pale yellow solid. (4: R = Rꢁ = Ph). Yield: ca. 60%. 31P NMR: δ −6.4. 1H NMR: δ 0.08
(s, Me3SiN), 6.8–7.2 (m, C6H4), 7.2–7.4 (m, Ph). 13C NMR: δ 2.1 (s, Me3SiN), 135.7 (d,
PC6H4, C1, JPC = 21.3), 128.4 (d, PC6H4, C2,6, JPC = 7.2), 133.6 (d, PC6H4, C3,5, JPC
=
19.1), 149.2 (s, PC6H4, C4), 137.8 (d, PPh, C1, JPC = 11.3), 130.3 (d, PPh, C2,6, JPC
=
7.4), 134.1 (d, PPh, C3,5, JPC = 20.0), 128.5 (s, PPh, C4). Anal. Calcd. for C24H32NPSi2:
C, 68.36; H, 7.65. Found: C, 67.99; H, 8.02.
In the same manner, the reaction of B with Ph(Me)PCl (E), freshly prepared as
described above, afforded (disilylanilino)phosphine 5 as a colorless liquid. (5: R = Ph, Rꢁ
= Me). Yield: 62%. bp: 135–139◦C (0.03 mm Hg). 31P NMR: δ −27.1. 1H NMR: δ 0.00

(DISILYLANILINO)PHOSPHINES
2161
(s, Me3SiN), 1.54 (d, PMe, JPH = 3.6), 6.8–7.2 (m, C6H4), 7.2–7.3 (m, Ph). 13C NMR: δ
0.0 (s, Me3SiN), 10.8 (d, PMe, JPH = 13.3), 126.1 (d, PC6H4, C1, JPC = 22.2), 131.5 (d,
PC6H4, C2,6, JPC = 9.5), 130.5 (d, PC6H4, C3,5, JPC = 19.6), 146.7 (s, PC6H4, C4), 139.1
(d, PPh, C1, JPC = 12.4), 128.1 (d, PPh, C2,6, JPC = 7.2), 129.7 (d, PPh, C3,5, JPC = 18.1),
126.2 (s, PPh, C4). Anal. Calcd. for C19H30NPSi2: C, 63.46; H, 8.41. Found: C, 63.25; H,
9.19.
Preparation of (Disilylanilino)phosphines, (M3Si)2NC6H4P(R)N
(SiMe3)2 (6–11)
A typical experiment for the synthesis of 6 (R = Me) is described here. A three-neck
(1000 mL) round-bottom flask, equipped with a mechanical stirrer, N2 inlet, and an addition
funnel was charged with Et2O (200 mL) and (Me3Si)2NH (8.25 g, 51.1 mmol). The mixture
was cooled to 0◦C and n-BuLi (21.6 mL, 54.0 mmol) was added slowly. The mixture was
allowed to warm to room temperature and was stirred for 1 h. The mixture was then cooled
to −78◦C and PCl3 (7.08 g, 51.6 mmol) was added slowly. The mixture was allowed to
warm to room temperature and was stirred for 2 h. The mixture was again cooled to 0◦C
and a previously prepared solution of the organolithium reagent B (51.2 mmol) was added
slowly via cannula. The reaction mixture was allowed to warm to room temperature and
was stirred for 2 h. To replace the remaining chlorine, the mixture was again cooled to
0◦C and CH3MgBr (17.3 mL, 52 mmol) was added slowly from the addition funnel. After
warming to room temperature, the mixture was stirred for ca. 3 h. Most of the solvents were
removed under reduced pressure and hexane (300 mL) was added to precipitate the salt.
After filtration and solvent removal under reduced pressure, fractional distillation afforded
6 as a colorless liquid. (6: R = Me). Yield: 62%. bp: 75–80◦C (0.10 mm Hg). 31P NMR: δ
38.5. 1H NMR: δ 0.01 (s, Me3SiN), 0.08 (s, Me3SiNP), 1.56 (d, PMe, JPH = 5.7), 6.8–7.2
(m, C6H4). 13C NMR: δ 0.0 (s, Me3SiN), 2.1 (s, Me3SiNP), 14.9 (d, PMe, JPC = 25.0),
139.2 (d, PC6H4, C1, JPC = 18.3), 126.9 (d, PC6H4, C2,6, JPC = 15.8), 127.7 (s, PC6H4,
C3,5), 144.8 (s, PC6H4, C4). Anal. Calcd. for C19H43N2PSi4: C, 51.52; H, 9.78. Found: C,
51.93; H, 10.88.
Compounds 7–10 were prepared in the same manner using the appropriate Grignard
(i-PrMgBr) or lithium reagent RLi [R = n-Bu, OCH2CF3, C6H4N(SiMe3)2], instead of
MeMgBr. All were obtained as colorless liquids after fractional distillation. (7: R = i-Pr).
Yield: 50%. bp: 130–135◦C (0.01 mm Hg). 31P NMR: δ 57.8. 1H NMR: δ 0.00 (s, Me3SiN),
0.08 (s, Me3SiNP), 1.07 (dd, PCHMe2, JPH = 21.9, JHH = 6.9), 1.15 (dd, PCHMe2, JPH
= 16.2, JHH = 6.3), 2.35 (ds, PCHMe2, JPH = 6.6, JHH = 6.9), 6.7–7.3 (m, C6H4). 13
C
NMR: δ 0.1 (s, Me3SiN), 2.5 (d, Me3SiNP, JPC = 6.6), 17.5 (d, PCHMe2, JPC = 11.2), 18.8
(d, PCHMe2, JPC = 37.6), 24.7 (d, PCHMe2, JPC = 18.4), 136.0 (d, PC6H4, C1, JPC = 23.6),
128.9 (d, PC6H4, C2,6, JPC = 15.5), 127.7 (s, PC6H4, C3,5), 145.6 (s, PC6H4, C4). Anal.
Calcd. for C21H47N2PSi4: C, 53.56; H, 10.06. Found: C, 52.41; H, 10.26. (8: R = n-Bu).
Yield: 59%. bp: 128–133◦C (0.10 mm Hg). 31P NMR: δ 47.6. 1H NMR: δ 0.01 (s, Me3SiN),
0.09 (s, Me3SiNP), 0.94 (t, CH2CH3, JHH = 6.6), 1.5–1.6 (m, PCH2CH2, CH2CH3),
1.9–2.0 (m, PCH2) 6.8–7.2 (m, C6H4). 13C NMR: δ 0.0 (s, Me3SiN), 2.3 (d, Me3SiNP, JPC
= 6.6), 11.9 (s, CH2CH3), 22.4 (d, CH2CH3, JPC = 13.6), 26.2 (d, PCH2CH2, JPC = 20.3),
29.5 (d, PCH2, JPC = 21.2), 138.7 (d, PC6H4, C1, JPC = 21.6), 127.1 (d, PC6H4, C2,6, JPC
= 15.2), 127.7 (s, PC6H4, C3,5), 144.8 (s, PC6H4, C4). Anal. Calcd. for C22H49N2PSi4:
C, 54.49; H, 10.18. Found: C, 53.27; H, 10.87. (9: R = OCH2CF3). Yield: ca. 60%.

2162
P. DEVULAPALLI ET AL.
1
bp: 93–96◦C (0.10 mm Hg). 31P NMR: δ 150.2. H NMR: δ 0.01 (s, Me3SiN), 0.11 (s,
Me3SiNP), 4.0–4.2 (m, OCH2CF3), 6.8–7.2 (m, C6H4). 13C NMR: δ 0.0 (s, Me3SiN), 1.9
(d, Me3SiNP, JPC = 7.2), 63.9 (dq, OCH2CF3, JPC = 27.5, JFC = 35.2), 123.5 (dq, JPC
=
6.2, JFC = 278.0), 139.2 (d, PC6H4, C1, JPC = 18.3), 126.9 (d, PC6H4, C2,6, JPC = 15.8),
127.7 (s, PC6H4, C3,5), 144.8 (s, PC6H4, C4). Anal. Calcd. for C20H42F3ON2PSi4: C, 45.59;
H, 8.03. Found: C, 45.73; H, 7.84. (10: R = C6H4N(SiMe3)2). Yield: 46%. bp: 170–180◦C
(0.01 mm Hg). 31P NMR: δ 48.9. 1H NMR: δ 0.02 (s, Me3SiN), 0.08 (s, Me3SiNP), 6.8–7.3
(m, C6H4). 13C NMR: δ 0.0 (s, Me3SiN), 2.2 (d, Me3SiNP, JPC = 7.2), 133.1 (d, PC6H4, C1,
JPC = 21.0), 128.9 (d, PC6H4, C2,6, JPC = 19.6), 127.4 (s, PC6H4, C3,5), 146.7 (s, PC6H4,
C4). Anal. Calcd. for C30H62N3PSi6: C, 54.24; H, 9.41. Found: C, 54.50; H, 9.17.
Compound 11 was prepared in the same manner starting from PhPCl2 instead of
PCl3. Fractional distillation afforded 11 as a colorless liquid. (11: R = Ph). Yield: 58%.
1
bp: 149–152◦C (0.10 mm Hg). 31P NMR: δ 48.9. H NMR: δ 0.00 (s, Me3SiN), 0.02
(s, Me3SiNP), 6.8–7.3 (m, C6H4), 7.3–7.5 (m, Ph). 13C NMR: δ 0.1 (s, Me3SiN), 2.4 (d,
Me3SiNP, JPC = 7.0), 138.8 (d, PC6H4, C1, JPC = 23.4), 129.3 (d, PC6H4, C2,6, JPC
=
19.6), 129.3 (d, PC6H4, C3,5, JPC = 19.0), 146.7 (s, PC6H4, C4), 133.2 (d, PPh, C1, JPC
=
21.2), 127.6 (d, PPh, C2,6, JPC = 5.4), 128.8 (d, PPh, C3,5, JPC = 5.0), 125.4 (s, PPh, C4).
Anal. Calcd. for C24H45N2PSi4: C, 57.09; H, 8.98. Found: C, 56.93; H, 9.43.
Preparation of (Disilylanilino)phosphines, (M3Si)2NC6H4P(R)Ph (12, 13)
A solution of the silylaniline reagent B (141 mmol) in Et2O (300 mL) was prepared
(as described above in the synthesis of 1). The mixture was cooled to −78◦C and PhPCl2
(25.1 g, 140.0 mmol) was slowly added via syringe. The mixture was allowed to warm
to 0◦C and was stirred for 2 h before n-BuLi (56.0 mL, 140.0 mmol) was slowly added.
The mixture was allowed to warm to room temperature and was stirred for 3 h. The ether
was removed under reduced pressure and hexane was added to precipitate the salt. After
filtration and solvent removal under reduced pressure, fractional distillation afforded 12 as
a colorless liquid. (12: R = Ph, Rꢁ = n-Bu). Yield: 50%. bp: 140–144◦C (0.01 mm Hg). 31
P
NMR: δ −16.2. 1H NMR: δ 0.01 (s, Me3SiN), 0.84 (t, CH2CH3, JHH = 6.3), 1.3–1.4 (m,
PCH2CH2, CH2CH3), 1.9–2.0 (m, PCH2), 6.8–7.2 (m, C6H4), 7.3–7.5 (m, PPh). 13C NMR:
δ 0.0 (s, Me3SiN), 11.7 (s, CH2CH3), 22.2 (d, CH2CH3, JPC = 13.3), 26.1 (d, PCH2CH2,
JPC = 10.6), 26.2 (d, PCH2, JPC = 4.9), 131.1 (d, PC6H4, C1, JPC = 19.0), 130.3 (d, PC6H4,
C2,6, JPC = 17.9), 127.0 (s, PC6H4, C3,5), 146.8 (s, PC6H4, C4), 125–133 (m, PPh). Anal.
Calcd. for C22H36NPSi2: C, 65.78; H, 9.03. Found: C, 65.51; H, 9.98.
Similarly, the one-step reaction of the silylaniline reagent B (100 mmol) with PhPCl2
(50 mmol) afforded 13 as a colorless liquid. (13: R = Ph, Rꢁ = C6H4N(SiMe3)2). Yield:
1
55%. bp: 180–186◦C (0.01 mm Hg). 31P NMR: δ −7.0. H NMR: δ 0.00 (s, Me3SiN),
6.8–7.2 (m, C6H4), 7.3–7.5 (m, PPh). 13C NMR: δ 0.0 (s, Me3SiN), 131.8 (d, PC6H4, C1,
JPC = 19.9), 131.4 (d, PC6H4, C2,6, JPC = 19.2), 128.0 (s, PC6H4, C3,5), 146.8 (s, PC6H4,
C4), 126–136 (m, PPh). Anal. Calcd. for C30H49N2PSi4: C, 62.01; H, 8.50. Found: C, 62.20;
H, 8.45.
FUNDING
The authors thank the Robert A. Welch Foundation (Grant P-0759) and the TCU
Research Fund for financial support of this work.

(DISILYLANILINO)PHOSPHINES
2163
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