Organophosphorus compounds; 142:1 A simple approach to 1,2,4-selena-and telluradiphospholes from phosphaalkynes and the chalcogen elements and a first study of their reactivity

Article abstract of DOI:10.1055/s-1999-3573

Phosphaalkynes 3 react with elemental selenium or tellurium to furnish the 1,2,4-selena- (5) or 1,2,4-telluradiphospholes (15), respectively. Although the telluradiphospholes 15 do not exhibit any selective cycloaddition reactivity, two equivalents of the phosphaalkyne 3 do undergo cycloaddition to the selenadiphospholes 5 through a [4+2]/[2+2+2] sequence to afford the tetracyclic products 8. The crystal structure of compound 8a has been determined. This cage compound is alkylated at P-4 on reaction with methyl trifluoromethanesulfonate to give 10 while selenium and sulfur react at P-7 of 8 to afford 11a,b. Compound 8a reacts with bromine by way of P/P bond cleavage and an unexpected rearrangement to furnish another tetracyclic compound 12 with a novel structure that has been confirmed by X-ray crystallography.

Full text of DOI:10.1055/s-1999-3573

1642
PAPER
Organophosphorus Compounds; 142:1 A Simple Approach to 1,2,4-Selena-
and Telluradiphospholes from Phosphaalkynes and the Chalcogen Elements
and a First Study of their Reactivity
Sven M. F. Asmus, Uwe Bergsträßer, Manfred Regitz*
Fachbereich Chemie der Universität Kaiserslautern, Erwin-Schrödinger-Straße, D-67663 Kaiserslautern, Germany
Fax +49(631)2053921; E-mail: regitz@rhrk.uni-kl.de
Received 20 February 1999
Dedicated to Professor José Elguero on the occasion of his 65th birthday.
Abstract: Phosphaalkynes 3 react with elemental selenium or tellu-
rium to furnish the 1,2,4-selena- (5) or 1,2,4-telluradiphospholes
(15), respectively. Although the telluradiphospholes 15 do not ex-
hibit any selective cycloaddition reactivity, two equivalents of the
phosphaalkyne 3 do undergo cycloaddition to the selenadiphosp-
holes 5 through a [4+2]/[2+2+2] sequence to afford the tetracyclic
products 8. The crystal structure of compound 8a has been deter-
mined. This cage compound is alkylated at P-4 on reaction with me-
thyl trifluoromethanesulfonate to give 10 while selenium and sulfur
react at P-7 of 8 to afford 11a,b. Compound 8a reacts with bromine
by way of P/P bond cleavage and an unexpected rearrangement to
furnish another tetracyclic compound 12 with a novel structure that
has been confirmed by X-ray crystallography.
Key words: phosphaacetylenes, chalcogenes, heterophospholes,
Diels–Alder reaction, cage compounds
Scheme 1
Introduction
ethylamine leads to the 1,2,4-selenadiphospholes 5
(Scheme 2). The simple and economic workup involves
coordinated phosphorus compounds are the synthesis of
Two major aspects of current research in the field of low-
merely filtration from excess selenium with subsequent
bulb-to-bulb distillation and furnishes the products in
yields of up to 89%. The analytical data of 5a,b agree with
those reported in the literature. The novel products 5c,d
show comparable chemical shift values in their NMR
spectra: in particular the 31P NMR signals with shifts of
d = 255.8 (263.9) and 287.2 (292.9) and couplings of
2J(P,P) = 49 (48) Hz and 1J(P,Se) = 449 (379) Hz identify
the compounds as 1,2,4-selenadiphospholes. In addition,
the MS and HRMS data confirm the elemental composi-
tion and constitution of 5c,d.
phospholes with additional heteroatoms2-5 and the con-
struction of phosphorus-containing cage compounds.6 A
further as yet neglected aspect is the reactivity of kineti-
cally stabilized phosphaalkynes 3 towards the elements
selenium and tellurium.
1,2,4-Selenadiphospholes 5 were previously only accessi-
ble by thermolysis of 1,2,3-selenadiazole (1) in the pres-
ence of phosphaalkynes with yields not exceeding 17%.
Probable intermediates in this process are the 1,3-dipole 2
and the 1,3-selenadiphospholes 44 (Scheme 1). There is
also a report that the reaction of a 1,2,4-triphosphole with
elemental selenium furnishes the 1,2,4-selenadiphosphole
5a, again only in modest yield.7
A plausible mechanism for the formation of the selenad-
iphospholes 5 involves the intermediate formation of the
selenoxophosphinidenes 7, generated in turn by ring
opening of the selenaphosphirenes 6. The 1,3-dipoles 7A
↔ 7B then undergo regioselective [3+2] cycloaddition to
a second equivalent of the respective phosphaalkyne 3
(Scheme 2).
We now report on a higher-yielding synthesis of the 1,2,4-
selenadiphosphole 5 and their tellurium analogues 15 as
well as the results of a first investigation of their reactivi-
ties.
A New Approach to 1,2,4-Selenadiphospholes 5
[4+2] Cycloadditions of 5 with Phosphaacetylenes 3
The reaction of an excess of elemental selenium (black or
gray modification) with the phosphaalkynes 3a–d in tolu-
ene at 70°C in the presence of an equimolar amount of tri-
Use of a deficit of selenium in the reactions with the phos-
phaalkynes 3a,c resulted in the formation of the tetracy-
clic products 8a,c in very good yields; in the case of 3b,
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A Simple Approach to 1,2,4-Selena- and Telluradiphospholes
1643
tures were elucidated mainly on the basis of the 31P NMR
spectra as discussed below for the example of product 8a.
The 31P NMR spectrum of 8a contains a pseudo-triplet
signal at δ = -100.5, i.e. in the high-field region typical
for a phosphirane system. The pseudo-triplet structure due
to selenium satellite signals [1J(P,Se) = 223 Hz] confirms
the direct adjacency of the selenium nucleus and thus the
unambiguous assignment of this signal to P-4. A second
signal at δ = 123.5, indicative of a l3s3-phosphorus atom
(P-1), exhibits a double double doublet structure. In addi-
2
tion to the coupling with P-4, J(P,P) couplings to P-8
(16.7 Hz) and P-7 (38.5 Hz) are also observed. Phospho-
rus P-7 is assigned to the double double doublet signal at
δ = 136.6 which, with its significantly large coupling of
1J(P,P) = 282.0 Hz, confirms the existence of the P−P in-
crement. The AMNX spin system at δ = 411.1 is unequiv-
ocally due to a l3s2-phosphorus atom (P-8) on account of
its extreme low-field position. The 13C NMR data support
the deductions from the 31P NMR spectrum (see experi-
mental section) while an X-ray crystallographic analysis
(Figure 1) irrevocably confirms the structure of this novel
cage compound.
Scheme 2
which can only be used as a solution in hexamethyldisi-
loxane, the corresponding reaction furnished 8b in only
18% yield (Scheme 3).
Selected bond length [Å] and angles [°]: Se-C(6) 1.989(2), Se-P(4)
2.2390(7), P(1)-C(9) 1.856(2), P(1)-C(6) 1.884(2), P(1)-C(2)
1.916(2), P(8)-C(9) 1.690(2), P(8)-P(7) 2.2267(9), P(7)-C(6)
1.864(2), P(7)-C(3) 1.886(2), P(4)-C(3) 1.863(2), P(4)-C(2)
1.864(2), C(2)-C(3) 1.574(3); C(6)-Se-P(4) 91.33(6), C(9)-P(1)-
C(6) 97.09(9), C(9)-P(1)-C(2) 99.53(9), C(6)-P(1)-C(2) 94.02(9),
C(9)-P(8)-P(7) 98.25(7), C(6)-P(7)-C(3) 94.86(10), C(6)-P(7)-
P(8) 95.82(7), C(3)-P(7)-P(8) 97.45(7), C(3)-P(4)-C(2) 49.94(9),
C(3)-P(4)-Se 100.81(7), C(2)-P(4)-Se 100.86(7), P(7)-C(6)-P(1)
102.39(9), P(7)-C(6)-Se 105.25(10), P(1)-C(6)-Se 103.89(10),
P(8)-C(9)-P(1) 117.47(11), C(3)-C(2)-P(4) 64.99(10), C(3)-
C(2)-P(1) 110.42(14), P(4)-C(2)-P(1) 112.13(10), C(2)-C(3)-P(4)
65.07(10),
C(2)-C(3)-P(7)
111.06(14),
P(4)-C(3)-P(7)
Scheme 3
112.82(10)17
Figure 1 Crystal Structure of 8a
Elemental analysis as well as the HR and EI mass spectra
confirm the compositions of compounds 8a–c. The struc-
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1644
S. M. F. Asmus et al.
PAPER
The phosphaalkene unit in the structure is characterized
by the typical P/C double bond length8 of 1.690(2) Å as
well as the planar geometry at C-9 (angular
sum = 359.7°). In addition, the C-9/C-t-Bu bond length of
1.557(3) Å is somewhat shorter than the analogous bond
lengths of the sp3-hybridized skeletal carbon atoms to the
respective t-butyl groups of around 1.582(3) Å. The P/P
bond length between P-8 and P-7 is 2.2267(9) Å. The P/C
bond lengths lie between 1.856(2) and 1.886(2) Å and are
thus in the usual range for P/C single bonds.9 The three-
membered ring contains two almost identical bond
lengths of 1.863(2) Å (P-4/C-3) and 1.864(2) Å (P-4/C-2)
which are somewhat longer than the published average
value of 1.835 Å for phosphiranes. Accordingly the C-2/
C-3 bond length of 1.574(3) Å is markedly longer while
the internal angle at P4 of 49.9° is only slightly larger than
the average literature values (1.525 Å and 49°) for this
class of compounds.10
For a reasonable discussion of the mechanism of forma-
tion of the tetracyclic compounds 8a–c we must assume
that the 1,2,4-selenadiphospholes 5a–c are intermediates.
They then undergo a [4+2] cycloaddition with one equiv-
alent of the phosphaalkyne 3a-c to furnish the 7-selena-
Scheme 4
1,3,5-triphosphabicyclo[2.2.1]hepta-2,5-dienes
9a–c
nish the cage compound 11a oxidized at P-7 (Scheme 4).
The composition of the product is confirmed by mass
spectrometry and oxidation at the P-7 position is clearly
demonstrated by the NMR data.12 All signals in the 31P
NMR spectrum experience a slight shift to higher field.
Retention of the P-7/P-8 bond with concomitant conver-
sion of P-7 to a l5-phosphorus atom is demonstrated by
which react in a homo Diels–Alder process with another
equivalent of the phosphaalkyne 3a–c to afford the prod-
ucts 8a–c. The intermediates 9a–c cannot be isolated or
even detected in the reaction mixture by NMR spectrosco-
py.
In contrast, the phospholes 5a–c can be observed in the re-
action mixture by 31P NMR spectroscopy. Furthermore, it
was found in an independent experiment that compound
5a does react with 2 equivalents of 3a to furnish 8a in
comparable yield.
1
the significant increase in the J(P,P) coupling to 339.5
Hz. At the same time, 77Se-satellite splitting of the P-7 sig-
nal with the typically large 1J(P,Se) coupling of 740 Hz is
seen. The low field position of the 31P NMR signal for P-
8 at d = 343.8 unambiguously demonstrates retention of
the l3-phosphaalkene unit so that an attack of selenium at
P-8 can be excluded with certainty.
The 13C NMR data of 11a differ only marginally from
those of the starting material; the only conspicuous feature
is the untypical breakdown of the coupling between C-6
and the neighboring, selenium-substituted phosphorus
atom P-7.
Alkylation and Oxidation of Selenatetraphosphatet-
racyclononene 8a
a) Alkylation with Methyl Trifluoromethanesulfonate
Treatment of the tetraphosphatetracyclononene 8a with
methyl trifluoromethanesulfonate in toluene at 25°C fur-
nishes the sulfonate 10 in a surprising selectivity (Scheme
4). In the 31P NMR spectrum of 10 the signal for P-8
(d = 412.7) remains more or less unchanged while those
for P-7 (d = 46.6) and P-1 (d = 80.5) experience pro-
nounced shifts to higher field. The signal for P-4 is shifted
by Dd = +10 ppm to a value observed previously for the
alkylated phosphorus atom in a comparable cage struc-
ture.11 In the 13C NMR spectrum, the typical coupling of
the signal at d = 17.8 for the methyl group with the phos-
phorus atom P-4 [1J(C,P) = 26.9 Hz] confirms the postu-
lated structure.
c) Reaction with Sulfur
The reaction of 8a with S8 in the presence of 15 mol%
Et3N is complete within 24 h and affords the cage com-
pound 11b with a sulfur substituent at P-7. The retention
of the cage structure is apparent from the 31P and 13C
NMR spectra.
The increase in the P-7/P-8 coupling to 1J(P,P) = 417.8 Hz
again indicates that the sulfur substitution must have oc-
curred at one of these positions. Since the P-8/C-9 cou-
1
pling decreases to J(P,C) = 60 Hz, the formation of a
methylenethioxophosphorane unit can be discounted as
such a structure would require a value of more than 100
Hz.13 At the same time, high field shifts are experienced
not only by the 31P NMR signal of P8 (to d = 239) but also
b) Reaction with Selenium
Gray selenium reacts with 8a in the presence of a catalytic
amount of triethylamine even at room temperature to fur-
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PAPER
A Simple Approach to 1,2,4-Selena- and Telluradiphospholes
1645
by the 13C NMR signal of C-9 (to d = 162.2); these obser- by the typical bond lengths of 2.271(2) Å (Se/P1) and
vations are attributed to the formation of the unusual con- 2.231(3) Å (Se/P8), respectively, similar in length to the
jugated S=P-P=C system.
one P/Se bond in 8a.
Reaction of the Tetracyclic Compound 8a with Bro-
mine
When an equimolar amount of elemental bromine is slow-
ly added to a solution of 8a in dichloromethane at -78°C
and the solution is allowed to thaw and is then stirred for
24 hours a yellow flaky precipitate of 12 is formed
(Scheme 5). The pure product is obtained by crystalliza-
tion from THF at -20°C. Mass spectrometric analysis
clearly shows that two bromine atoms have been added to
the tetracyclic compound 8a.
Selected bond length [Å] and angles [°]: Br(2)-P(8) 2.312(2), Br(1)-
P(5) 2.286(2), Se(9)-P(8) 2.231(3), Se(9)-P(1) 2.271(2), P(3)-C(2)
1.846(8), P(3)-C(4) 1.874(7), P(3)-C(7) 1.902(8), P(1)-C(6)
1.871(7), P(1)-C(2) 1.878(7), P(8)-C(7) 1.930(7), P(5)-C(4)
1.817(7), P(5)-C(6) 1.885(7), C(2)-C(4) 1.580(9), C(7)-C(6)
1.604(10); P(8)-Se(9)-P(1) 95.67(8), C(2)-P(3)-C(4) 50.3(3),
C(2)-P(3)-C(7) 99.1(3), C(4)-P(3)-C(7) 99.1(3), C(6)-P(1)-C(2)
92.9(3), C(6)-P(1)-Se(9) 94.7(2), C(2)-P(1)-Se(9) 108.9(2), C(7)-
P(8)-Se(9) 99.1(2), C(7)-P(8)-Br(2) 104.5(2), Se(9)-P(8)-Br(2)
99.32(10), C(4)-P(5)-C(6) 93.8(3), C(4)-P(5)-Br(1) 99.7(2),
C(6)-P(5)-Br(1) 106.4(2), C(4)-C(2)-P(3) 65.8(4), C(4)-C(2)-
P(1) 107.3(4), P(3)-C(2)-P(1) 109.6(4), C(2)-C(4)-P(5) 112.9(5),
C(2)-C(4)-P(3) 63.9(4), P(5)-C(4)-P(3) 106.6(4), C(6)-C(7)-P(3)
104.2(5), C(6)-C(7)-P(8) 108.7(5), P(3)-C(7)-P(8) 107.6(3),
C(7)-C(6)-P(1) 106.3(5), C(7)-C(6)-P(5) 102.6(5), P(1)-C(6)-
P(5) 98.9(3)17
Figure 2 Crystal Structure of 12
Scheme 5
The angle at selenium is now expanded to 95.7°. The
phosphirane unit (C-2/P-3/C-4) shows a slight deviation
from the symmetry since the bond lengths P-3/C-2
(1.846(8)) and P-3/C-4 (1.874(7)) differ and both exceed
the reported average bond length of 1.835 Å for phos-
phacyclopropanes. Similarly, the C-2/C-4 bond length of
1.580(9) Å varies markedly and the internal angle at P-3
of 50.3(3)° also varies, albeit only slightly, from the pub-
lished average values (1.525 Å and 49°) for phos-
phiranes.10
The 31P NMR spectrum reveals the presence of four non-
equivalent phosphorus atoms. On comparison with the
spectrum of 8a it is apparent that (a) the phosphaalkene
unit is no longer intact since the signal at lowest shift is
now found at d = 221.7, (b) there is no P/P bond because
large P/P coupling constants are absent, and (c) a phos-
phirane unit is present as by a signal at d = −126.3. Two
of the phosphorus signals (d = 149.5 and. 221.7) exhibit
1J(P,Se) couplings of between 216.8 and 339.8 Hz, indic-
ative of a rearrangement of the tetracyclic skeleton.
Most of the P-C bond lengths are between 1.817(7) and
1.885(7) Å and thus in the usual range for P-C single
bonds.9 Exceptions are the P-3/C-7 bond length of
1.902(8) Å and the P-8/C-7 bond length of 1.930(7) Å
which are stretched somewhat on account of the steric sit-
uation.
An X-ray crystallographic analysis demonstrated the
structure of compound 12. The rearrangement of the skel-
eton is first obvious from the fact that the selenium atom
is now bonded to two phosphorus substituents as shown
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1646
S. M. F. Asmus et al.
PAPER
gel was heated for 3 h in vacuo and then deactivated with 4% H2O
(Brockmann activity II). The bulb-to-bulb distillations were carried
out in a Büchi GKR 50 apparatus, the temperatures stated are oven
temperatures. Melting points were determined on a Mettler FP61
apparatus (heating rate 2°C/min) and are uncorrected. Microanaly-
ses were performed with a Perkin-Elmer Analyzer 2400. 1H NMR
and 13C NMR spectra were recorded with Bruker AC 200 and Bruk-
er AMX 400 spectrometers and referenced to the solvent as internal
standard. 31P NMR spectra were measured on a Bruker AC 200
(80.8 MHz) spectrometer with 85% H3PO4 as external standard. MS
and HRMS were recorded on a Finnigan MAT 90 spectrometer at
70 eV ionization voltage. IR spectra were measured on a Perkin-
Elmer 16 PC FT-IR spectrophotometer.
In analogy to the well-known P/P bond cleavage by
halogens18 the initial step in the mechanism is assumed to
be the diastereoselective19 formation of the intermediate
13 which, however, cannot be detected by spectroscopy.
Then, the tetracyclic product 12 is generated in a two-step
process involving rearrangement (13 → 14) and subse-
quent intramolecularer 1,3-dipolar cycloaddition (→ 12).
Accordingly, the reaction is diastereoselective with regard
to the newly generated stereocenters P-5 and P-8, as is
confirmed by the NMR spectroscopic data.
1,2,4-Telluradiphospholes 15
1,2,4-Selenadiphospholes 5a–c; General Procedure
An excess of selenium, Et3N, and the corresponding phosphaacety-
Under harsher conditions (120°C in toluene in a Schlenk lene were heated in toluene (4 mL) in a Schlenk pressure tube at
70°C. After the reaction was over (ca. 24 h, 31P NMR monitoring),
pressure tube) the phosphaalkynes 3a–c exhibit an analo-
the residue was taken up in pentane (10 mL) and the insoluble ma-
gous reactivity towards elemental tellurium. In addition to
terial was removed by filtration through a D3 sinter filled to a depth
of 2 cm with Celite. The products were purified by bulb-to-bulb dis-
tillation.
oligomers of the phosphaalkyne, the previously unknown
1,2,4-telluradiphospholes 15a–c are formed (Scheme 6),
albeit in modest yields, through the postulated intermedi-
acy of a telluroxophosphinidene and subsequent [3+2] cy-
3,5-Di-tert-butyl-1,2,4-selenadiphosphole (5a)
From tert-butylphosphaacetylene (3a; 0.6 mL, 4.4 mmol), Et3N (0.6
mL, 4.4 mmol), and selenium (Segrey, 345 mg, 4.4 mmol); yield: 548
cloaddition with one equivalent of the phosphaalkyne.
The yellowish oils obtained tend to form amorphous crys-
tals, they are thermally labile and decompose unselective-
ly on exposure to light with deposition of elemental
tellurium.
mg (89%); bp 140°C/=0.001 mbar. Analytical data are identical to
those reported in the literature.4
3,5-Di-tert-pentyl -1,2,4-selenadiphosphole (5b)
From tert-pentylphosphaacetylene (3b; 110.1 mg, 0.96 mmol as a
26% solution in hexamethyldisiloxane), Et3N (130 µL, 0.96 mmol),
and selenium (Segrey, 76 mg, 0.96 mmol); yield: 116.7 mg (81%
based on the phosphaacetylene); bp 140°C/0.001 mbar. Analytical
data are identical to those reported in the literature.4
3,5-Diadamant-1-yl-1,2,4-selenadiphosphole (5c)
From adamant-1-ylphosphaacetylene (3c; 90 mg, 0.51 mmol), Et3N
(70 µL, 0.51 mmol), and selenium (49 mg, 0.62 mmol); yield: 88.8
mg (80%); mp 163°C.
1H NMR (CDCl3): δ = 1.45−1.75 (m, 15 H, 1-Ad), 1.85−2.20 (m, 15
H, 1-Ad).
13C NMR (CDCl3): d = 29.4 [d, J(C,P) = 2.3 Hz, CH], 29.5 [d,
4
4J(C,P) = 1.5 Hz, CH], 36.3 (s, CH2), 36.4 (s, CH2), 45.2 [dd,
Scheme 6
2
2
2J(C,P) = 19.1, J(C,P) = 16.8 Hz, i-C], 45.6 [dd, J(C,P) = 15.3,
3J(C,P) = 5.3 Hz, i-C], 48.2 [dd, J(C,P) = 14.5, J(C,P) = 9.9 Hz,
3
3
3
1
CH2], 48.5 [d, J(C,P) = 12.2 Hz, CH2], 216.2 [dd, J(C,P) = 66.8,
The compositions and constitutions of these novel hetero-
cyclic compounds were confirmed by high resolution
mass spectrometry and by their characteristic NMR spec-
tra. A conspicuous feature is the close positioning of the
two 31P NMR signals at (for 15a) d = 299.6 and 302.5 with
2J(C,P) = 5.5 Hz, C-5], 223.5 [dd, J(C,P) = 85.4, J(C,P) = 73.2
1
1
Hz, C-3].
31P NMR (C6D6): d = 255.8 [d, 2J(P,P) = 49.3, 2J(P,Se) = 79 Hz, P-
4], 287.2 [d, 2J(P,P) = 49.3 Hz, 1J(P,Se) = 449 Hz, P-2].
MS (EI, 70 eV): m/z (%) = 436 (40, M+), 325 (100, M+ − SeP), 294
(12, 1-AdC≡C-1-Ad+), 147 (8, 1-AdC+), 135 (57, Ad+).
2
a J(P,P) coupling of 49 Hz. The 13C NMR spectrum of
15a reveals drastic downfield shifts for the ring carbon
atom signals which appear as double doublets at d = 212.3
and 227.0. Attempts to realize cycloaddition reactions
with the telluradiphospholes gave unselective results and,
in particular, did not lead to the formation of cage com-
pounds analogous to 8 (31P NMR monitoring).
HRMS: m/z calcd for C22H30P2Se 436.0988, found 436.0988.
3,5-Bis(1-methylcyclohex-1-yl)-1,2,4-selenadiphosphole (5d)
From 1-methylcyclohex-1-ylphosphaacetylene (3d; 104 mg, 0.74
mmol as a 17% solution in hexamethyldisiloxane), Et3N (70 mL
NEt3, 0.51 mmol), and selenium (68 mg, 0.86 mmol); yield: 98.6
mg (74%); bp 190°C/0.008 mbar.
1H NMR (C6D6): δ = 1.28−2.27 (m, 20 H, CH2), 1.42 (s, 3 H, CH3),
1.48 (s, 3 H, CH3).
All reactions were performed under argon (purity >99.998%) atmo-
sphere using Schlenk techniques. The solvents were dried by stan-
dard procedures, distilled, and stored under argon. Compounds 3a–
c were prepared by published methods.14 Column chromatography
was performed in water-cooled glass tubes under argon. The eluate
was monitored with a UV absorbance detector (l = 254 nm). Silica
4
13C NMR (C6D6): d = 22.8 [dd, 4J(C,P) = 3.0, J(C,P) = 1.0 Hz,
CH2], 22.9 [d, 4J(C,P) = 4.4 Hz, CH2], 25.9 (s, CH2), 25.9 (s, CH2),
26.0 (s, CH2), 35.1 (s, CH3), 35.2 (s, CH3), 42.5 [dd, 3J(C,P) = 14.9,
3J(C,P) = 10.4 Hz, CH2], 42.8 [d, 3J(C,P) = 12.8 Hz, CH2], 46.3 [dd,
2
2
2J(C,P) = 18.5, J(C,P) = 16.1 Hz, i-C], 46.9 [dd, J(C,P) = 14.4,
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A Simple Approach to 1,2,4-Selena- and Telluradiphospholes
1647
1
2
3J(C,P) = 5.9 Hz, i-C], 215.7 [dd, 1J(C,P) = 64.7, 2J(C,P) = 5.2 Hz,
C-5], 223.3 [dd, 1J(C,P) = 83.5, 1J(C,P) = 68.1 Hz, C-3].
2J(P,P) = 32.3 Hz, P-7], 410.3 [dd, J(P,P) = 281.2, J(P,P) = 18.4
Hz, P-8].
31P NMR (C6D6): d = 263.9 [d, 2J(P,P) = 48.4, 2J(P,Se) = 63 Hz, P-
MS (EI, 70 eV): m/z (%) = 536 (7, M+), 308 (42, P2C2-t-Pen2Se+),
4], 292.9 [d, 2J(P,P) = 48.4 Hz, 1J(P,Se) = 379 Hz, P-2].
259 (11, P3C2-t-Pen2 ), 197 [45, P(C-t-Pen)2 ], 145 (23, P2C-t-
+
+
+
Pen+), 83 (82, C-t-Pen+), 71 (40, C5H11+), 44 (100, C3H8 ).
MS (EI, 70 eV): m/z (%) = 360 (66, M+), 345 (8, M+ − CH3), 279
+
(79, M+ − SeH), 249 [27, P(CC7H13)2 ], 220 (13, SeP≡CC7H13+),
HRMS: m/z calcd for C24H44P4Se 536.1558, found 536.1558.
171 (9, P2CC7H13+), 109 (100, CC7H13+), 97 (60, C7H13+).
2,3,6,9-Tetraadamant-1-yl-5,1,4,7,8-selenatetraphosphatetra-
cyclo[4.3.0.02,4.03,7]non-8-ene (8c)
HRMS: m/z calcd for C16H26P2Se 360.0674, found 360.0674.
From adamant-1-ylphosphaacetylene (3c; 897 mg, 5 mmol) and se-
lenium (78 mg, 1 mmol); yield: 396 mg (49% based on selenium);
mp 236°C.
1H NMR (CDCl3): δ = 1.2 - 2.9 (unresolved signals).
13C NMR (C6D6): δ = 29.1 (s, Cc), 29.3 (s, Cc), 29.5 (s, Cc), 29.7 (s,
Cc), 36.3 (s, Cd), 36.4 (s, Cd), 36.5 (s, Cd), 36.6 (s, Cd), 39.1 - 48.7
5,1,4,7,8-Selenatetraphosphatetracyclo[4.3.0.02,4.03,7]non-8-
enes (8), General Procedure
Compounds 8 are best prepared by heating a mixture of an excess
of phosphaacetylenes 3a–c and selenium in toluene (5 mL) at 90°C
for 48 h in a Schlenk pressure tube. After cooling the reaction mix-
ture to 25°C, the excess of phosphaacetylene is removed at 25°C/
0.001 mbar. The orange residue is taken up in pentane/Et2O (1:2)
and subjected to column chromatography on silica gel (0.063 - 0.2
mm) with the same solvent mixture. After elution of a yellow frac-
tion containing the corresponding 1,2,4-selenadiphospholes 5a–c, a
second pale orange fraction was obtained that gave pure 8a-c after
evaporation of the solvent.
(unresolved
signals,
Ca
and
Cb),
66.9
[ptpt,
1J(C,P) = 1J(C,P) = 44.4, 2J(C,P)+3J(C,P) = 1.9 Hz, C-2], 74.1
[ddpt, 1J(C,P) = 1J(C,P) = 47.5, 2J(C,P) = 11.0, 2J(C,P) = 4.7 Hz,
1
1
2
C-3], 76.8 [ddd, J(C,P) = 38.7, J(C,P) = 30.8, J(C,P) = 1.9 Hz,
C-6], 243.0 [dd, 1J(C,P) = 78.6, 1J(C,P) = 67.5 Hz, C-9].
31P NMR (CDCl3): δ = −104.0 [s, 1J(P,Se) = 218 Hz, P-4], 112.1 [d,
2,3,6,9-Tetra-tert-butyl-5,1,4,7,8-selenatetraphosphatetracyc-
lo[4.3.0.02,4.03,7]non-8-ene (8a)
From tert-butylphosphaacetylene (3a; 0.26 mL, 2 mmol) and sele-
nium (Segrey, 32 mg, 0.4 mmol); yield: 167.1 mg (95%); mp 138°C.
1H NMR (C6D6): δ = 1.24 [s, 9 H, C(CH3)3], 1.33 [d, 4J(H,P) = 2.1
Hz, 9 H, C(CH3)3], 1.34 [s, 9 H, C(CH3)3], 1.56 [s, 9 H, C(CH3)3].
1
2J(P,P) = 34.9 Hz, P-1], 121.7 [dd, J(P,P) = 279.0, 2J(P,P) = 34.9,
P-7], 403.7 [d, 1J(P,P) = 279.0 Hz, P-8].
77Se NMR (CDCl3): δ = 67.2 [dd, 1J(Se,P) = 206 Hz, 2J(Se,P) = 23
Hz].
MS (EI, 70 eV): m/z (%) = 792 (6, M+), 712 (10, M+ − Se), 356 (4,
PC∫1-Ad+), 325 [33, P(C-1-Ad)2 ], 294 (46, 1-AdC∫C-1-Ad+), 135
+
13C NMR (C6D6): δ = 34.6 [dpt, 3J(C,P)
4J(C,P) = 2.1 Hz, C(CH3)3], 35.1 [ddd, 2J(C,P) = 26.7,
2J(C,P) = 9.6, 3J(C,P) = 1.9
Hz, C(CH3)3], 35.9 [pt,
+
3J(C,P) = 4.2,
(100, 1-Ad+).
HRMS: m/z calcd for C44H60P4Se 792.2811, found 792.2811.
3J(C,P)+3J(C,P) = 12.4 Hz, C(CH3)3], 36.0 [dd, 3J(C,P) = 12.4,
3J(C,P) = 6.7 Hz, C(CH3)3], 36.7 [ddd, 3J(C,P) = 9.9, 3J(C,P) = 6.6,
4J(C,P) = 3.3 Hz, C(CH3)3], 37.1 [ddd, 2J(C,P) = 18.1,
2J(C,P) = 12.4, 3J(C,P) = 2.9 Hz, C(CH3)3], 37.8 [ddd,
2J(C,P) = 11.9, 2J(C,P) = 9.5, 3J(C,P) = 2.9 Hz, C(CH3)3], 44.6 [dd,
2J(C,P) = 20.0, 2J(C,P) = 12.4 Hz, CMe3 at C-9], 66.4 [ptpt, 1J(C,P)
2,3,6,9-Tetra-tert-butyl-4-methyl-5,1,4,7,8-selenatetraphos-
phatetracyclo[4.3.0.02,4.03,7]non-8-ene Trifluoromethane-
sulfonate (10)
To a magnetically stirred solution of 8a (119.1 mg, 0.24 mmol) in
toluene (3 mL) at 25°C was added methyl triflate (28 mL, 0.24
mmol). After 4 h, the solution turned yellow and the volatile com-
ponents were removed at 25°C/0.001mbar. The yellow residue was
taken up in CH2Cl2 and 10 was obtained as yellow needles by crys-
tallization at -78°C; yield: 141 mg (91%); mp 141°C.
+
1J(C,P) = 46.7, 3J(C,P) + 2J(C,P) = 4.5 Hz, C-2], 75.8 [ddpt,
1
2
1J(C,P) + J(C,P) = 46.3, 2J(C,P) = 12.4, J(C,P) = 6.2 Hz, C-3],
1
1
2
78.4 [ddd, J(C,P) = 41.0, J(C,P) = 32.4, J(C,P) = 2.9 Hz, C-6],
245.1 [dd, 1J(C,P) = 79.6 Hz, 1J(C,P) = 67.2 Hz, C-9].
1H NMR (CDCl3): δ = 1.20 [s, 9 H, C(CH3)3], 1.33 [d, 4J(H,P) = 2.5
Hz, 9 H, C(CH3)3], 1.38 [d, 4J(H,P) = 2.5 Hz, 9 H, C(CH3)3], 1.56
[s, 9 H, C(CH3)3], 2.62 [d, 2J(H,P) = 11.2 Hz, 3 H, CH3].
31P NMR (C6D6): δ = −100.5 [pt, 3J(P,P) + 2J(P,P) = 6.9 Hz,
1J(P,Se) = 223 Hz, P-4], 123.5 [ddd, 2J(P,P) = 38.5, 2J(P,P) = 16.7,
2J(P,P) = 6.9 Hz, P-1], 136.6 [ddd, 1J(P,P) = 282.0, 2J(P,P) = 38.5,
2J(P,P) = 4.2 Hz, P-7], 411.1 [ddd, 1J(P,P) = 282.0, 2J(P,P) = 16.7,
3J(P,P) = 6.9 Hz, P-8].
13C NMR (CDCl3): δ = 17.8 [d, 1J(C,P) = 26.9 Hz, CH3 at P-4], 34.1
3
3
[s, C(CH3)3], 34.2 [pt, J(C,P) + J(C,P) = 2.7 Hz, C(CH3)3], 34.8
[pt, 3J(C,P) + 3J(C,P) = 1.9 Hz, C(CH3)3], 35.4 [dpt, 2J(C,P) +
2J(C,P) = 8.5, 3J(C,P) = 1.9 Hz, C(CH3)3], 35.8 [ptd, 3J(C,P) = 9.4,
3J(C,P) + 4J(C,P) = 1.9 Hz, C(CH3)3], 37.2 [dd, 2J(C,P) = 19.6,
2J(C,P) = 14.2 Hz, C(CH3)3], 38.8 [dd, 2J(C,P) = 11.7, 2J(C,P) = 3.1
Hz, C(CH3)3], 45.8 [dd, 2J(C,P) = 7.5, 2J(C,P) = 6.8 Hz, C(CH3)3 at
C-9], 61.9 [pt, 1J(C,P) + 1J(C,P) = 48.3 Hz, C-2], 66.0 [ddd,
1
2
77Se NMR (C6D6): δ = 59.2 [dd, J(Se,P) = 209 Hz, J(Se,P) = 22
Hz]
MS (EI, 70 eV): m/z (%) = 480 (51, M+), 369 (6, M+ − SeP), 349 (6,
+
+
M+ − P2C-t-Bu), 231 (39, P3C-t-Bu2 ), 169 [100, P(C-t-Bu)2 ], 131
(20, P2C-t-Bu+), 69 (20, C-t-Bu+), 57 (15, C4H9 ).
+
1
2
1J(C,P) = 76.3, J(C,P) = 52.5, J(C,P) = 6.2 Hz, C-6], 69.2 [ddd,
C20H36P4Se
(479.4)
calcd
C
50.11
50.22
H
7.57
7.71
1J(C,P) = 43.6, 1J(C,P) = 42.0, J(C,P) = 1.6 Hz, C-3], 120.5 [q,
2
found
1J(C,F) = 320.4 Hz, CF3], 203.1 [dd, 1J(C,P) = 85.7 Hz,
1J(C,P) = 25.2 Hz, C-9].
2,3,6,9-Tetrakis-tert-pentyl-5,1,4,7,8-selenatetraphosphatetra-
cyclo[4.3.0.02,4.03,7]non-8-ene (8b)
From tert-pentylphosphaacetylene (3b; 2.7 mL, 5 mmol as a 26%
solution in hexamethyldisiloxane) and selenium (Segrey, 87 mg, 1.1
mmol); yield: 106 mg (18%); mp 151°C.
31P NMR (C6D6): δ = −91.5 [s, 1J(P,Se) = 219.9 Hz, P-4], 46.6 [d,
2
1J(P,P) = 263.9 Hz, P-7], 80.5 [d, J(P,P) = 22.3 Hz, P-1], 412.7
[dd, 1J(P,P) = 263.9, 2J(P,P) = 22.3 Hz, P-8].
MS (EI, 70 eV): m/z (%) = 495 (52, M+), 417 (100, M+ − P2CH3),
+
+
31P NMR (C6D6): δ = −99.8 [s, 1J(P,Se) = 246 Hz, P-4], 122.7 [dd,
231 [28, P3(C-t-Bu)2 ], 169 [78, P(C-t-Bu)2 ], 131 (41, P2C-t-Bu+),
2J(P,P) = 32.3, 2J(P,P) = 18.4 Hz, P-1], 133.9 [dd, J(P,P) = 281.2,
69 (38, C-t-Bu+), 57 (45, C4H9 ).
1
+
HRMS: m/z calcd for C21H39P4Se 495.1167, found 495.1166.
Synthesis 1999, No. 9, 1642–1650 ISSN 0039-7881 © Thieme Stuttgart · New York

1648
S. M. F. Asmus et al.
PAPER
2,3,6,9-Tetra-tert-butyl-7-selenoxo-5,1,4,7,8-selena-
MS (EI, 70 eV): m/z (%) = 512 (47, M+), 480 (13, M+ − S), 280 [5,
tetraphosphatetracyclo[4.3.0.02,4.03,7]non-8-ene (11a)
P2(C-t-Bu)2Se+], 231 (20, P3C-t-Bu2 ), 169 [100, P(C-t-Bu)2 ], 131
(19, P2C-t-Bu+), 69 (42, C-t-Bu+), 57 (41, t-Bu+).
+
+
To a magnetically stirred solution of 8a (216 mg, 0.45 mmol) in tol-
uene (3 mL) at 25°C were added selenium (Segrey, 35 mg, 0.45
mmol) and Et3N (10 mL, 0.07 mmol). After 6 d the volatile compo-
nents were removed at 25°C/0.001 mbar. The orange residue was
taken up in pentane/Et2O (100:1) and subjected to column chroma-
tography on silica gel (0.063 - 0.2 mm) with the same solvent mix-
ture. The first pale orange fraction was collected to give pure 11a
after evaporation of the solvent; yield: 203 mg (81%); mp 158°C.
HRMS: m/z calcd for C20H36P4SSe 512.0597, found 512.0597.
5,8-Dibromo-2,4,6,7-tetra-tert-butyl-9-selena-1,3,5,8-tetraphos-
phatetracyclo[4.3.0.02,4.03,7]-nonane (12)
To a magnetically stirred solution of 8a (55 mg, 0.12 mmol) in
CH2Cl2 (3 mL) at −78°C was added slowly Br2 (18.3 mg, 0.12
mmol). The mixture was allowed to warm to r.t. and stirred for 24 h
to complete the reaction. The color of the solution changed slowly
to bright yellow. After the volatile components were removed at
25 °C/0.001 mbar 12 was purified by recrystallization from THF to
give yellow crystals; yield: 55.2 mg (72%); mp 152°C.
1H NMR (C6D6): δ = 1.26 [s, br, 9 H, C(CH3)3], 1.39 [s, 9 H,
C(CH3)3], 1.49 [s, 9 H, C(CH3)3], 1.72 [s, 9 H, C(CH3)3].
13C NMR (C6D6): δ = 33.5 [pt, 3J(C,P) + 3J(C,P) = 2.9 Hz,
C(CH3)3], 34.4 [dd, 2J(C,P) = 12.6, 2J(C,P) = 6.5 Hz, C(CH3)3],
3
3
1H NMR (CDCl3): δ = 1.50 [s, 9 H, C(CH3)3], 1.52 [dd,
35.3 [s, br, C(CH3)3], 36.0 [dd, J(C,P) = 16.8, J(C,P) = 11.2 Hz,
C(CH3)3], 36.6 [dd, 2J(C,P) = 9.5, 2J(C,P) = 6.8 Hz, C(CH3)3], 37.8
4J(H,P) = 3.7, 4J(H,P) = 2.0 Hz, 9 H, C(CH3)3], 1.54 [dd,
2
2
3
4J(H,P) = 3.4, 4J(H,P) = 1.7 Hz,
4J(H,P) = 2.5 Hz, 9 H, C(CH3)3].
9 H, C(CH3)3], 1.71 [d,
[dpt, J(C,P) = 12.9, J(C,P) + J(C,P) = 2.4 Hz, C(CH3)3], 38.9
[ptd, 2J(C,P) = 8.8, 2J(C,P) + 3J(C,P) = 2.3 Hz, C(CH3)3], 44.4 [ddd,
2J(C,P) = 20.9, 2J(C,P) = 11.3, 3J(C,P) = 8.9 Hz, CMe3 at C-9], 53.5
2
31P NMR (CDCl3): δ = −126.3 [d, J(P,P) = 8.1, P-4], 149.5 [dd,
1
1
2
[ddd, J(C,P) = 43.3, J(C,P) = 27.7, J(C,P) = 4.8 Hz, C-2], 72.3
2
1
2J(P,P) = 28.5, J(P,P) = 8.1, J(P,Se) = 216.8 Hz, P-1], 159.5 [d,
2J(P,P) = 8.1 Hz, P-5], 221.7 [dd, 2J(P,P) = 28.5, 2J(P,P) = 8.1,
1J(P,Se) = 339.8 Hz, P-8].
1
1
2
[ddd, J(C,P) = 59.1, J(C,P) = 42.9, J(C,P) = 4.8 Hz, C-3], 76.2
[dd, 1J(C,P) = 41.4, 1J(C,P) = 2.9 Hz, C-6], 243.3 [ddd,
1J(C,P) = 74.6, 1J(C,P) = 69.6, 2J(C,P) = 3.4 Hz, C-9].
MS (EI, 70 eV): m/z (%) = 640 (4, M+), 559 (16, M+ − Br), 480 [19,
31P NMR (C6D6): δ = −123.3 [s, br, 1J(P,Se) = 209 Hz, P-4], 43.3 [d,
2J(P,P) = 34.9, P-1], 99.0 [dd, 1J(P,P) = 339.5, 2J(P,P) = 34.9,
1J(P,Se) = 744 Hz, P-7], 343.8 [d, 1J(P,P) = 339.5 Hz, P-8].
M+ − 2Br], 400 (4, M+ − 2Br − Se), 231 [99, P3C-t-Bu+], 169 (100,
+
P(C-t-Bu)2 ), 131 (12, P2C-t-Bu+), 69 (7, C-t-Bu+), 57 (9, t-Bu+).
HRMS: m/z calcd for C20H36Br2P4Se 637.9301, found 637.9302.
IR (C7H8): ν = 3059 (C−H), 3031 (C−H), 3017 (C−H), 2919 (C−H),
1492, 1456, 1077, 729, 794 cm-1.
C20H36Br2 P4Se
(479.4)
calcd
C
37.58
37.31
H
5.68
5.43
MS (EI, 70 eV): m/z (%) = 560 (10, M+), 480 (37, M+ − Se), 369 (6,
found
+
M+ − Se2P), 349 (6, M+ − Se − P2C-t-Bu), 280 [4, Se(C-t-Bu)2P2 ],
+
+
231 [39, P3(C-t-Bu)2 ], 169 [100, P(C-t-Bu)2 ], 131 (17, P2C-t-Bu+),
1,2,4-Telluradiphospholes 15a-c, General Procedure
+
69 (20, C-t-Bu+), 57 (15, C4H9 ).
An excess of Te and the corresponding phosphaacetylene were
heated in toluene (4 mL) in a Schlenk pressure tube at 120°C. After
the reaction was over (31P NMR monitoring), the residue was taken
up in pentane (10 mL) and the insoluble material was removed by
filtration through a D3 sinter filled to a depth of 3 cm with Celite.
The products were purified by bulb-to-bulb distillation.
HRMS: m/z calcd for C20H36P4Se2 560.0098, found 560.0098.
2,3,6,9-Tetra-tert-butyl-7-thioxo-5,1,4,7,8-selenatetraphospha-
tetracyclo[4.3.0.02,4.03,7]non-8-ene (11b)
To a magnetically stirred solution of 8a (214 mg, 0.45 mmol) in tol-
uene (3 mL) at r.t. were added sulfur (S8, 14 mg, 0.45 mmol) and
Et3N (10 mL, 0.07 mmol). The color of the solution changed slowly
to bright yellow. After 24 h the volatile components were removed
at 25°C/0.001 mbar and 11b was purified by recrystallization from
CH2Cl2 to give yellow needles; yield: 212 mg (92%); mp 150°C.
3,5-Di-tert-butyl-1,2,4-telluradiphosphole (15a)
From tert-butylphosphaacetylene (3a; 0.13 mL, 1.0 mmol) and tel-
lurium (128 mg, 1.0 mmol); yield: 25 mg (15% based on phos-
phaacetylene); bp 105°C/0.001 mbar.
4
1H NMR (C6D6): δ = 1.47 [d, J(H,P) = 1.27 Hz, 9 H, C(CH3)3],
1.66 [d, 4J(H,P) = 2.04 Hz, 9 H, C(CH3)3].
1H NMR (C6D6): δ = 1.34 [s, 9 H, C(CH3)3], 1.39 [s, 9 H, C(CH3)3],
1.45 [s, 9 H, C(CH3)3], 1.65 [d, 4J(H,P) = 1.0 Hz, 9 H, C(CH3)3].
13C NMR (CDCl3): δ = 33.8 [dd, 3J(C,P) = 10.5, 3J(C,P) = 8.7 Hz,
3-C(CH3)3], 35.1 [d, 3J(C,P) = 11.3 Hz, 5-C(CH3)3], 42.3 [pt,
2J(C,P) = 2J(C,P) = 19.9 Hz, 3-C(CH3)3], 43.5 [d, 2J(C,P) = 20.8
Hz, 5-C(CH3)3], 212.3 [dd, 1J(C,P) = 61.0, 2J(C,P) = 9.2 Hz, C-5],
227.0 [dd, 1J(C,P) = 82.7, 1J(C,P) = 65.8 Hz, C-3].
3
3
13C NMR (C6D6): δ = 32.8 [dd, J(C,P) = 11.0, J(C,P) = 6.6 Hz,
C(CH3)3], 33.4 [pt, 3J(C,P) + 3J(C,P) = 4.7 Hz, C(CH3)3], 35.2 [dd,
2J(C,P) = 12.9, 2J(C,P) = 1.7 Hz, C(CH3)3], 35.5 [dd,
3J(C,P) = 11.9, 3J(C,P) = 10.2 Hz, C(CH3)3], 36.5 [dd,
3J(C,P) = 12.3, 3J(C,P) = 7.2 Hz, C(CH3)3], 36.8 [ddd,
2J(C,P) = 15.8, 2J(C,P) = 9.3, 3J(C,P) = 1.8 Hz, C(CH3)3], 38.4
[ddd, 2J(C,P) = 12.3, 2J(C,P) = 8.7, 3J(C,P) = 2.6 Hz, C(CH3)3],
2
31P NMR (C6D6): δ = 299.6 [d, J(P,P) = 49.1 Hz, P-4], 302.5 [d,
2J(P,P) = 49.1 Hz, P-2].
2
2
MS (EI, 70 eV): m/z (%) = 330 (23, M+), 230 (15, M+ − P∫C-t-Bu),
199 (2, M+ − TeH), 169 (66, [(t-BuC)2P]+), 161 (9, [Te−P]+), 99 (87,
M+ − P∫C-t-Bu − TeH), 69 (74, [C-t-Bu]+), 57 (12, [t-Bu]+).
40.2 [dd, J(C,P) = 17.7, J(C,P) = 5.9 Hz, C(CH3)3 at C-9], 66.9
[m, 1J(C,P) = 45.2, 1J(C,P) = 42.4, 2J(C,P) = 10.7, 3J(C,P) = 6.8
Hz, C-2], 69.6 [ddpt, 1J(C,P) + 1J(C,P) = 47.6, 2J(C,P) = 27.2,
1
2J(C,P) = 5.6 Hz, C-3], 72.1 [dddd, 1J(C,P) = 37.3, J(C,P) = 29.6,
HRMS: m/z calcd for C10H18P2Te 329.9951, found 329.9951.
3
1
2J(C,P) = 11.8, J(C,P) = 3.4 Hz, C-6], 162.2 [ddd, J(C,P) = 61.0,
3,5-Di-tert-pentyl-1,2,4-telluradiphosphole (15b)
From tert-pentylphosphaacetylene (3b; 114.1 mg, 1.0 mmol as a
26% solution in hexamethyldisiloxane) and Te (128 mg, 1.0 mmol);
yield: 36 mg (20% based on the phosphaacetylene); bp 110°C/0.001
mbar.
1J(C,P) = 11.8, 2J(C,P) = 3.4 Hz, C-9].
31P NMR (C6D6): δ = −91.8 [pt, 2J(P,P)+3J(P,P) = 6.3,
1J(P,Se) = 207 Hz, P-4], 107.6 [ddd, 1J(P,P) = 417.8,
2J(P,P) = 24.1, 2J(P,P) = 6.3 Hz, P-7], 118.3 [pt, 2J(P,P)
+
2J(P,P) = 26.0 Hz, P-1], 239.4 [ddd, 1J(P,P) = 417.8, 2J(P,P) = 26.0,
3J(P,P) = 6.3 Hz, P-8].
3
1H NMR (C6D6): δ = 0.79 [t, J(H,H) = 7.48 Hz, 3 H, CH2CH3],
0.83 [t, 3J(H,H) = 7.38 Hz, 3 H, CH2CH3], 1.46 [d, 4J(H,P) = 1.79
Hz, 6 H, 5-C(CH3)2], 1.63 [d, 4J(H,P) = 2.69 Hz, 6 H, 3-C(CH3)2],
Synthesis 1999, No. 9, 1642–1650 ISSN 0039-7881 © Thieme Stuttgart · New York

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A Simple Approach to 1,2,4-Selena- and Telluradiphospholes
1649
1.69 [q, 2 H, 3J(H,H) = 7.48 Hz, CH2CH3], 2.03 [q, 2 H,
3J(H,H) = 7.38 Hz, CH2CH3].
Structure solution and refinement: The structure was solved using
direct methods (SHELXS-86)15 and refined with the full matrix
least squares procedure against F2 (SHELXL-93).16 The anisotropic
refinement converged at R1 = 0.0698 and wR2 = 0.1626 [I>2s(I)]
and R1 = 0.0954, wR2 = 0.1755 (all data). The difference Fourier
synthesis on the basis of the final structural model showed a maxi-
mum of 1324 e/nm3 and a minimum of -1021 e/nm3.17
13C NMR (CDCl3): δ = 9.2 [d, 4J(C,P) = 1.0 Hz, 3-/5-CH2CH3], 9.3
[d, 4J(C,P) = 2.1 Hz, 3-/5-CH2CH3], 31.9 [dd, 3J(C,P) = 17.9,
3J(C,P) = 10.5 Hz, 3-C(CH3)2], 33.7 [d, 3J(C,P) = 14.7 Hz, 5-
C(CH3)2], 40.7 [dd, 3J(C,P) = 10.5, 3J(C,P) = 7.4 Hz, 3-CCH2], 42.2
3
2
2
[d, J(C,P) = 6.8 Hz, 5-CCH2], 48.4 [pt, J(C,P) + J(C,P) = 17.9
Hz, 3-C(CH3)2], 49.3 [d, 2J(C,P) = 21.0 Hz, 5-C(CH3)2], 208.5 [dd,
1J(C,P) = 66.1, J(C,P) = 7.6 Hz, C-5], 226.9 [dd, J(C,P) = 86.5,
2
1
Acknowledgement
1J(C,P) = 76.3 Hz, C-3].
We are grateful to the Deutsche Forschungsgemeinschaft (Gradu-
iertenkolleg “Phosphor als Bindeglied verschiedener chemischer
Disziplinen”) for a postgraduate grant (S. A.). We are also indebted
to the Fonds der Chemischen Industrie for generous financial sup-
port.
2
31P NMR (C6D6): δ = 301.9 [d, J(P,P) = 52.5 Hz, P-4], 305.6 [d,
2J(P,P) = 52.5 Hz, P-2].
MS (EI, 70 eV): m/z (%) = 358 (78, M+), 329 (62, M+ − CH2CH3),
244 (17, M+ − P∫C-t-Pen), 227 (8, M+ − TeH), 197 (55, M+ − TeP),
113 (100, M+ − P∫C-t-Pen − TeH), 83 (60, C-t-Pen+).
HRMS: m/z calcd for C12H22P2Te 358.0265, found 358.0265.
References
3,5-Diadamant-1-yl-1,2,4-telluradiphosphole (15c)
From adamant-1-ylphosphaacetylene (3c; 205 mg, 1.15 mmol) and
Te (190 mg, 1.5 mmol), yield: 42 mg (15% based on the phos-
phaacetylene), bp 215 °C/0.001 mbar.
1H NMR (CDCl3): δ = 1.56−1.97 (m, 15 H, 1-Ad), 2.00−2.42 (m, 15
H, 1-Ad).
(1) Part 141, see: Löber, O.; Bergsträßer U.; Regitz, M. Synthesis
1999, 644.
(2) (a) Schmidpeter, A.; Karaghiosoff, K. In Multiple Bonds and
Low Coordination in Phosphorus Chemistry; Regitz, M.;
Scherer, O. J., Eds.; Thieme: Stuttgart, 1990; p 258.
(b) Regitz, M. In Multiple Bonds and Low Coordination in
Phosphorus Chemistry; Regitz, M.; Scherer, O. J., Eds.;
Thieme: Stuttgart 1990; p 58.
(3) Bansal, R. K.; Karaghiosoff, K.; Gandhi, N.; Schmidpeter, A.
Synthesis 1995, 361.
(4) Regitz, M.; Krill S. Phosphorus, Sulfur, and Silicon 1996,
115, 99.
13C NMR (CDCl3): d = 28.9 (s, CH), 29.1 (s, CH), 36.2 (s, CH2),
36.5 (s, CH2), 47.1 [dd, 2J(C,P) = 21.1, 2J(C,P) = 14.7 Hz, i-C], 47.4
2
3
3
[dd, J(C,P) = 19.7, J(C,P) = 7.2 Hz, i-C], 49.0 [d, J(C,P) = 11.1
Hz, CH2], 49.2 [d, 3J(C,P) = 9.8 Hz, CH2], 213.7 [dd,
1J(C,P) = 60.7, J(C,P) = 8.1 Hz, C-5], 229.1 [dd, J(C,P) = 83.4,
2
1
1J(C,P) = 66.7 Hz, C-3].
2
31P NMR (C6D6): δ = 292.7 [d, J(P,P) = 51.0 Hz, P-4], 295.7 [d,
(5) Regitz, M. Chem. Rev. 1990, 90, 191.
2J(P,P) = 51.0 Hz, P-2].
(6) Mack, A.; Regitz M. Chem. Ber. 1997, 130, 823.
(7) Caliman, V.; Hitchcock P. B.; Nixon, J. F.; Sakarya, N. Bull.
Soc. Chim. Belg. 1996, 105, 675.
(8) Appel, R. In Multiple Bonds and Low Coordination in
Phosphorus Chemistry; Regitz, M.; Scherer, O. J., Eds.;
Thieme: Stuttgart, 1990; p 157.
(9) CRC Handbook of Chemistry and Physics, 73rd Ed.; Lide, D.
R., Ed.; CRC Press: Boca Raton, 1992, p 9-1.
(10) Mathey, F. Chem. Rev. 1990, 90, 997.
(11) Julino, M.; Bergsträßer, U.; Regitz M. Synthesis 1992, 87.
(12) Main structural features of 11a were proved by an X-ray
structure analysis. A discussion of structural details is not
possible due to the poor quality of the data set.
(13) Niecke, E.; Böske, J.; Krebs, B.; Dartmann, M. Chem. Ber.
1985, 118, 3227.
(14) Rösch, W.; Allspach, T.; Bergsträßer, U.; Regitz, M. In
Synthetic Methods of Organometallic and Inorganic
Chemistry, Vol. 3; Herrmann, W. A., Ed.; Thieme: Stuttgart,
1996, p 11.
(15) Sheldrick, G. M., Fortran Program for the Solution of Crystal
Structures from Diffraction Data, Institute for Organic
Chemistry, University of Göttingen, 1986.
(16) Sheldrick, G. M., Fortran Program for Crystal Structure
Refinement, Institute for Organic Chemistry, University of
Göttingen, 1993.
+
MS (EI, 70 eV): m/z (%) = 486 (8, M+), 325 [100, P(C-1-Ad)2 ],
294 (27, 1-AdC∫C-1-Ad+), 147 (4, 1-AdC+), 135 (21, 1-Ad+).
HRMS: m/z calcd for C22H30P2Te 486.0892, found 486.0891.
Crystal Structure Analysis of 8a
Crystal Data: C20H36P4Se, Mr = 479.33, monoclinic, space group
P21/c,
a = 1627.7(3),
b = 974.5(2),
c = 1619.9(3)
pm,
b = 114.80(3)°, V = 2.3325(8) nm3, Z = 4, dc = 1.365 Mg/m3.
Data collection: The data collection was performed using an Imag-
ing Plate Diffraction System (STOE-IPDS) at r.t. Crystal dimen-
sions:0.40 × 0.30 × 0.15 mm. The measurements were made in the
range 2.51<θ<25.97°, l = 0.71073 MoKa (graphite monochroma-
tor), -20 ≤ h ≤ 19, -11 ≤ k ≤11, -19 ≤ l ≤ 19, a total of 19595 re-
flections, of which 4425 (3632 with I>2s(I)) were independent
reflections.
Structure solution and refinement: The structure was solved using
direct methods (SHELXS-86)15 and refined with the full matrix
least squares procedure against F2 (SHELXL-93).16 The anisotropic
refinement converged at R1 = 0.0305 and wR2 = 0.0664 [I>2s(I)]
and R1 = 0.0392, wR2 = 0.0680 (all data). The difference Fourier
synthesis on the basis of the final structural model showed a maxi-
mum of 476 e/nm3 and a minimum of -279 e/nm3.17
Crystal Structure Analysis of 12
(17) Crystallographic data (excluding structure factors) for the
structure reported in this paper have been deposited with the
Cambridge Crystallographic Data Centre as supplementary
publication no. CCDC-11481 (8a) and CCDC-11482 (12).
Copies of the data can be obtained free of charge on
application to: CCDC, 12 Union Road, Cambridge CB21EZ,
UK (fax +44 122 3336033; e-mail: deposit@ccdc.cam.ac.uk).
(18) (a) Geißler, B. Ph.D Thesis, University of Kaiserslautern,
1993.
Crystal Data: C20H36Br2P4Se, Mr = 639.15, monoclinic, space
group P21/n, a = 907.1(2), b = 2723.3(5), c = 1008.7(2) pm,
b = 90.10(3)°, V = 2.4918(9) nm3, Z = 4, dc = 1.704 Mg/m3.
Data collection: The data collection was performed using an Imag-
ing Plate Diffraction System (STOE-IPDS) at r.t. Crystal dimen-
sions:0.30 × 0.20 × 0.15 mm. The measurements were made in the
range 2.15<θ<25.10°, l = 0.71073 MoKa (graphite monochroma-
tor), -10 ≤ h ≤ 10, -32 ≤ k ≤ 32, -11 ≤ l ≤ 10, a total of 16688 re-
flections, of which 4232 (2873 with I>2s(I)) were independent
reflections.
(b) Birkel, M. Ph. D. Thesis, University of Kaiserslautern,
Synthesis 1999, No. 9, 1642–1650 ISSN 0039-7881 © Thieme Stuttgart · New York

1650
S. M. F. Asmus et al.
PAPER
1992.
(c) Mack. A.; Regitz, M. Chem. Ber. Recueil 1997, 130, 823.
Article Identifier:
1437-210X,E;1999,0,09,1642,1650,ftx,en;Z01699SS.pdf
(19) Nachbauer A.; Bergsträßer U.; Leininger S.; Regitz M.
Synthesis 1998, 427.
Synthesis 1999, No. 9, 1642–1650 ISSN 0039-7881 © Thieme Stuttgart · New York