Synthesis and structure of eight-, nine-, and ten-membered rings with P-Se-Se-P linkages

Article abstract of DOI:10.1002/anie.200705021

Full circle: The reaction of [PhP(Se)(μ-Se)]₂ with alkyl or aryl diols affords five unusual P-Se heterocycles with eight-, nine-, and ten-membered rings containing P-Se-Se-P linkages. The structure of the ten-membered ring is shown. (Figure Pre

Full text of DOI:10.1002/anie.200705021

Angewandte
Chemie
DOI: 10.1002/anie.200705021
À
Organic P Se Rings
Synthesis and Structure of Eight-, Nine-, and Ten-Membered Rings
with P-Se-Se-P Linkages
Guoxiong Hua, Yang Li, Alexandra M. Z. Slawin, and J. Derek Woollins*
Organoselenium compounds are studied
because of their interesting reactivities and
potential biological or pharmaceutical signifi-
cance. Organic diselenides, as useful synthetic
reagents and intermediates, have played an
important role in organoselenium chemistry, as
they are stable, easily handled, and reactive
enough to generate electrophilic, nucleophilic,
and radiophilic species.[1] There are only a few
examples of macrocycles containing diselenide
linkages,[2] and many of the known routes to
diselenides in general suffer from the use of
highly toxic H2Se, harsh reaction conditions,
low yields, or complicated manipulations.
We are developing the chemistry of 2,4-
bis(phenyl)-1,3-diselenadiphosphetane-2,4-dis-
Scheme 1. Synthesis of 1–3.
elenide [PhP(Se)(m-Se)]2 (known as Woollinsꢀ
reagent, WR).[3] Herein, we report the syn-
À
thesis of five novel P Se diselenides with eight-, nine- and
ten-membered rings; this is the first reported synthesis of such
large-ring diselenides bearing the P-Se-Se-P linkage.
À80 ppm; 1J(P,Seexo) = 822, 810, and 806 Hz, respectively) and
endocyclic selenium atoms (d = 491, 441, and 441 ppm). The
X-ray structures of 1–3 (Figure 1) confirm the presence of the
eight-, nine-, and ten-membered rings. Both R,R and S,S
enantiomers are present in all the structures, and no R,S/S,R
diastereomers are observed. The macrocyclic framework is
highly puckered with the two phenyl rings on opposite sides of
Cleavage of the four-membered P2Se2 ring in WR by alkyl
diols affords the corresponding bis(diselenophosphonic) acids
quantitatively as yellow oils. These acids were converted into
the corresponding amine salts by treatment with butylamine
and were oxidized using I2/KI to give eight-, nine- and ten-
membered-ring diselenides 1–3 (70–90% yields, Scheme 1).
Compounds 1–3 are soluble in common polar organic
solvents and were crystallized from dichloromethane solu-
tions with slow diffusion of hexane to give transparent,
colorless, cubic crystals. The compounds are stable to air and
moisture for several months. The 31P NMR spectra of 1–3
exhibit sharp singlets at d ꢀ 67 ppm, which are accompanied
by two sets of satellites for the endocyclic and exocyclic
À
the heterocycle. The Se Se bond (2.3393(12), 2.3518(7), and
2.3475(6) Š in 1–3, respectively) is slightly shorter than that in
acyclic structures containing the P-Se-Se-P linkage
(2.384(1) Š).[5] The geometry around P(1) and P(2) is
distorted tetrahedral (Se(1)-P(1)-Se(2) and Se(3)-P(2)-
Se(4): 103.94(9) and 105.25(9), 105.49(6) and 105.76(6),
103.94(9) and 106.04(5)8 for 1–3, respectively).
Heating equimolar amounts of aromatic diol and WR at
reflux in toluene for 15 h affords, after workup in air,
diselenides 4 and 5 as white crystals in 61% and 65% yields
(Scheme 2). 4 and 5 are soluble in organic solvents, are air-
stable, and display the expected NMR spectra. The X-ray
structures of 4 and 5 (Figure 2) are similar to the structures of
1–3, although the P(1)-Se-Se angles (106.83(4), 107.27(4)8 for
4 and 106.22(5), 108.18(5)8 for 5) are larger than in 1–3.
selenium atoms (1J(P,Seendo) and J(P,Seexo): 444 and 822 Hz
for 1, 465 and 812Hz for 2, and 460 and 808 Hz for 3), thus
indicating the presence of single and double P Se bonds in
each compound. Detailed NMR spectroscopic analysis
reveals the relatively small coupling constant between
phosphorus atoms (3J(P,P) = 3.0–4.7 Hz), supporting the pres-
ence of the P-Se-Se-P group (cf. 3J(P,P) = 4 Hz for the
analogous P-S-S-P system).[4] The 77Se NMR spectra for 1–3
contain signals arising from exocyclic (d = À75, À61, and
1
À
À
Since the Se Se bond is labile and can be broken easily,
À
studies to use these P Se heterocyclic diselenides as multi-
donor ligands and as synthetic precursors are now underway.
[*] Dr. G. Hua, Dr. Y. Li, Prof. A. M. Z. Slawin, Prof. J. D. Woollins
School of Chemistry, University of St Andrews
North Haugh, St Andrews, Fife, KY16 9ST (UK)
Fax : (+44)1334-463-384
Experimental Section
General procedure for synthesis of 1–3: A mixture of the appropriate
alkyl diol (1.0 mmol) and WR (0.54 g, 1.0 mmol) in toluene (20 mL)
was stirred at room temperature for 20 h. The red suspension changed
to a green solution along with a trace amount of black elemental
E-mail: jdw3@st-andrews.ac.uk
Homepage: http://chemistry.st-and.ac.uk/staff/jdw/group/
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Figure 2. Molecular structure (H atoms omitted for clarity) of a) 4;
selected bond lengths [Š]: Se(1)–P(1) 2.0888(14), Se(2)–P(1)
2.2371(13), O(1)–P(1) 1.612(3), Se(2)–Se(3) 2.3555(8), Se(3)–P(2)
2.0797(13), Se(4)–P(2) 2.2545(13), O(2)–P(2) 1.616(3); and b) 5;
selected bond lengths [Š]: Se(1)–P(1) 2.0745(17), Se(2)–P(1)
2.2413(17), O(1)–P(1) 1.612(4), Se(2)–Se(12) 2.3474(9), Se(11)–P(11)
2.0808(16), Se(12)–P(11) 2.2372(16), O(11)–P(11) 1.613(4).
Figure 1. Molecular structure (H atoms omitted for clarity), of a) 1;
selected bond lengths [Š]: Se(1)–P(1) 2.089(2), Se(2)–P(1) 2.253 (2),
O(1)–P(1) 1.573(6), Se(2)–Se(3) 2.3393(12), Se(4)–P(2) 2.085(2),
Se(3)–P(2) 2.243(2), O(2)–P(2) 1.586(6); b) 2; selected bond lengths
[Š]: Se(1)–P(1) 2.0788(13), Se(2)–P(1) 2.2605(13), O(1)–P(1) 1.584(3),
Se(2)–Se(3) 2.3518(7), Se(3)–P(2) 2.0821(14), Se(4)–P(2) 2.2468(14),
O(2)–P(2) 1.587(3); and c) 3; selected bond lengths [Š]: Se(1)–P(1)
2.0894(12), Se(2)–P(1) 2.2455(12), O(1)–P(1) 1.583(3), Se(2)–Se(3)
2.3475(6), Se(3)–P(2) 2.0869(12), Se(4)–P(2) 2.2488(12), O(2)–P(2)
1.581(3).
1: 90% yield. M.p. 1108C. Selected IR (KBr): n˜ = 1437(m),
1105(s), 1068(s), 1023(vs), 944(vs), 745(s), 711(m), 689(m), 537 cmÀ1
1
=
(s, P Se). H NMR (CD2Cl2): d = 8.02–7.53 (m, 10H, ArH), 5.30 (t,
J = 12Hz, 2H, CH 2), 4.22 ppm (t, J = 12Hz, 2H, CH 2). 13C NMR
(CD2Cl2): d = 132.9 (d, J(P,C) = 100 Hz),
130.4 (d, J(P,C) = 3 Hz), 128.5 (d, J(P,C) =
12Hz), 126.5 (d,
J(P,C) = 15 Hz),
66.1 ppm (s, CH2). 31P NMR (CD2Cl2):
d = 66.77 ppm, singlet with 77Se satellites
(2” AXX ’ pattern) (1J(P,Seexo) = 822 Hz,
1J(P,Seendo) = 444 Hz,
3J(P,P) = 3.0 Hz;
lines for 2J(P,Seendo) were hidden under
the intensive central line, prohibiting
calculation of the coupling constant).
77Se NMR (CD2Cl2): d = 490.66 (dd, J-
Scheme 2. Synthesis of 4 and 5.
(P,Seendo) = 443 Hz,
2J(P,Seendo) =
24.7 Hz), À74.59 ppm (d, J(P,Seexo) =
822 Hz). EI+ MS m/z: 592[ M]+. Elemen-
selenium. The resulting mixture was filtered and concentrated in
vacuo to give a green paste, which was dissolved in diethyl ether
(20 mL), and butylamine (0.5 mL) was added dropwise. This resulted
intermediately in a brown suspension and then a gray suspension after
30 min stirring at room temperature. The gray, solid dibutylammo-
nium bisdiselenophosphonates were obtained by filtration and
washed with diethyl ether.
A solution of KI/I2 (1.5 mmol) was added dropwise to a stirred
solution of the dibutylammonium bisdiselenophosphonate
(0.5 mmol) in THF (10 mL). An obvious white precipitate formed
immediately. The mixture was then stirred at room temperature for
another 1 h to ensure complete reaction and then reduced to dryness
in vacuo. The residue was dissolved in dichloromethane and filtered
to give a yellow solution and gray insoluble solid (polymer side
product). The filtrate was purified by silica gel chromatography
(dichloromethane as eluent) to give 1–3. Crystals were obtained from
dichloromethane solutions by diffusion of hexane.
tal analysis calcd (%) for C14H14O2P2Se4: C 28.4, H 2.4; found: C 28.0,
H 2.6.
2: 85% yield. M.p. 162–1638C. Selected IR (KBr): n˜ = 1433(m),
1262(m), 1103(s), 987(s), 804(m), 740(m), 684(m), 538 cmÀ1 (s, P Se).
=
1H NMR (CD2Cl2): d = 8.00–7.56 (m, 10H, ArH), 4.66 (m, J = 12Hz,
2H, CH2), 4.30 ppm (t, J = 12Hz, 4H, CH 2). 13C NMR (CD2Cl2): d =
135.1 (d, J(P,C) = 103 Hz), 133.2(d, 4J(P,C) = 3 Hz), 130.7 (d, 3J-
(P,C) = 12Hz), 128.6 (d, 2J(P,C) = 15 Hz), 62.4 (d, 2J(P,C) = 15 Hz,
CH2); 28.4 ppm (t, 3J(P,C) = 10 Hz, CH2). 31P NMR (CD2Cl2): d =
67.21 ppm (s, 1J(P,Seexo) = 812Hz, 1J(P,Seendo) = 465 Hz, 3J(P,P) =
4.2Hz; lines for 2J(P,Seendo) were hidden under the intensive central
line, prohibiting calculation of the coupling constant). 77Se NMR
(CD2Cl2): d = 441.17 (dd, 1J(P,Seendo) = 465, 2J(P,Seendo) = 21.5 Hz),
À61.15 ppm (dd, 1J(P,Seexo) = 810 Hz). High-resolution mass spec-
trometry (EIMS): 609.7284, calculated mass for C15H16O2P2Se4:
609.7281. Elemental analysis calcd (%) for C15H16O2P2Se4: C 29.7,
H 2.7; found C 29.5, H 2.8.
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3: 70% yield. M.p. 1088C. Selected IR (KBr): n˜ = 2948(m),
Crystal data for 1: C14H14O2P2Se4, Mr = 592.03, triclinic, space
¯
2882(w), 1435(s), 1381(w), 1105(s), 962(bs), 745(s), 711(s), 687(s),
group P1, a = 11.154(3), b = 13.120(2), c = 13.245(3) Š, a =
532cm À1 (s, P Se). 1H NMR (CD2Cl2): d = 8.04 m, 4H, ArH), 7.56
105.945(12), b = 90.097(14), g = 92.998(13)8, U = 1860.9(6) Š3, Z = 4,
m = 8.059 mmÀ1, 12374 reflections collected, 5465 observed independ-
ent reflections (Rint = 0.0355) gave R = 0.0692for I > 2s(I) and
wR(F2) = 0.1766.
=
(m, 6H, ArH), 4.39 (m, 3J(P,H) = 40 Hz, 3J(H,H) = 8.9 Hz, 4H, CH2),
2.04 ppm (m, 3J(H,H) = 8.9 Hz, 4H, CH2). 13C NMR (CD2Cl2): d =
137.5 (d, 1J(P,C) = 98 Hz), 132.3 (d, 4J(P,C) = 3 Hz), 129.6 (d, 3J(P,C) =
13 Hz), 128.4 (d, 2J(P,C) = 15 Hz), 65.9 (2J(P,C) = 32Hz, CH 2),
25.1 ppm (3J(P,C) = 8 Hz, CH2). 31P NMR (CD2Cl2): d = 68.28 ppm,
(s, 1J(P,Seexo) = 808 Hz, 1J(P,Seendo) = 460 Hz, 3J(P,P) = 4.7 Hz; lines
for 2J(P,Seendo) were hidden under the intensive central line, prohibit-
ing calculation of the coupling constant). 77Se NMR (CD2Cl2): d =
Crystal data for 2: C15H16O2P2Se4, Mr = 606.06, triclinic, space
¯
group P1, a = 8.9823, b = 9.5401, c = 11.8295 Š, a = 78.391(6), b =
88.090(7), g = 78.328(6)8, U = 972.4(2) Š3, Z = 2, m = 7.714 mmÀ1
,
6910 reflections collected, 3030 observed independent reflections
(Rint = 0.0402) gave R = 0.0443 for I > 2s(I) and wR(F2) = 0.0989.
Crystal data for 3: C16H18O2P2Se4, Mr = 620.08, monoclinic, space
group P21/n, a = 15.3206(17), b = 9.3686(9), c = 15.3675(18) Š, b =
109.91(2)8, U = 2074.8(4) Š3, Z = 4, m = 7.240 mmÀ1, 14276 reflections
collected, 3422 observed independent reflections (Rint = 0.0604) gave
R = 0.0426 for I > 2s(I) and wR(F2) = 0.0779.
1
2
474.21 (dd, J(P,Seendo) = 463 Hz, J(P,Seendo) = 21.5 Hz), À80.17 ppm
(d, 1J(P,Seexo) = 806 Hz). High-resolution mass spectrometry (EIMS):
621.7450, calculated mass for C16H18O2P2Se4: 621.7445. Elemental
analysis calcd (%) for C16H18O2P2Se4: C 31.0, H 2.9; found: C 30.5,
H 2.8.
General Procedure for synthesis of 4 and 5: A mixture of
aromatic diol (1.0 mmol) and WR (0.54 g, 1 mmol) in toluene (20 mL)
was heated at reflux for 15 h under N2. Upon cooling to room
temperature the mixture was purified by silica gel chromatography
(toluene as eluent) to afford diselenides 4 and 5 as white crystals.
4. 61% yield. M.p. 172–1738C. Selected IR (KBr): n˜ = 1577(w),
1502(m), 1452(m), 1469(m), 1435(m), 1182(s), 1099(s), 916(vs),
Crystal data for 4: C24H18O2P2Se4, Mr = 716.16, triclinic, space
¯
group P1, a = 9.2156(12), b = 9.9004(12), c = 14.797(2) Š, a =
72.569(14), b = 80.164(19), g = 72.384(17)8, U = 1222.9(3) Š3, Z = 2,
m = 6.151 mmÀ1, 8627 reflections collected, 3762 observed independ-
ent reflections (Rint = 0.0322) gave R = 0.0433 for I > 2s(I) and
wR(F2) = 0.0694.
Crystal data for 5: C33H24Cl2O2P2Se4, Mr = 901.20, triclinic, space
769(s), 743(s), 684(m), 557(m), 528 cmÀ1 (s, P Se). 1H NMR
group P1, a = 11.1080(7), b = 11.5793(10), c = 14.2126(10) Š, a =
¯
=
(CDCl3): d = 8.70 (d, J(H,H) = 8.2Hz, 4H, ArH), 7.61 (d, J(H,H) =
6.7 Hz, 2H, ArH), 7.48 (m, J(H,H) = 8.2Hz, 6H, ArH), 7.32 (dd,
J(H,H) = 6.7 Hz, 2H, ArH), 7.16 ppm (m, J(H,H) = 6.7 Hz, 4H,
ArH). 13C NMR (CDCl3): d = 134.0, 133.2, 132.5, 131.3, 131.2, 131.1,
129.5, 128.3, 128.2, 128.1, 125.6, 119.8, 119.7 ppm. 31P NMR (CDCl3):
87.875(8), b = 70.601(6), g = 74.137(6)8, U = 1655.7(2) Š3, Z = 2, m =
4.720 mmÀ1, 10839 reflections collected, 4543 observed independent
reflections (Rint = 0.0322) gave R = 0.0756 for I > 2s(I) and wR(F2) =
0.1049.
1
1
3
d = 67.21 ppm (s, J(P,Seexo) = 826 Hz, J(P,Seendo) = 507 Hz, J(P,P) =
Received: October 30, 2007
Revised: December 3, 2007
Published online: March 3, 2008
2
4.7 Hz; lines for J(P,Seendo) were hidden under the intensive central
line, prohibiting calculation of the coupling constant). 77Se NMR
(CDCl3): d = 505.36 (dd, 1J(P,Seendo) = 498 Hz, 2J(P,Seendo) = 23.9 Hz),
1
22.31 ppm (d, J(P,Seexo) = 826 Hz). High-resolution mass spectrom-
Keywords: heterocycles · phosphorus · selenium ·
X-ray diffraction
.
etry (EIMS): 717.7444, calculated mass for C24H18O2P2Se4: 717.7445.
Elemental analysis calcd (%) for C16H18O2P2Se4: C 40.1, H 2.5; found
C 40.3, H 2.9.
5: 65% yield. M.p. 140–1418C. Selected IR (KBr): n˜ = 1586(w),
1504(w), 1434(m), 1219(m), 1199(m), 1099(m), 1071(m), 986(s),
829(s), 812(m), 745(m), 695(m), 535(s), 481 cmÀ1 (m). 1H NMR
(CD2Cl2): d = 8.97 (d, J(H,H) = 9.1 Hz, 2H, NapH), 8.24 (d, J(H,H) =
9.1 Hz, 2H, NapH), 8.13 (d, J(H,H) = 8.2Hz, 2H, PhH), 7.90 (d,
J(H,H) = 8.2Hz, 4H, PhH), 7.59–7.28 (m, 8H, NapH + PhH),
7.10 ppm (d, J(H,H) = 9.1 Hz, 2H, NapH). 13C NMR (CD2Cl3): d =
152.9, 133.4 (d, J(P,C) = 33.2Hz), 131.4, 130.8 (d, J(P,C) = 13.5 Hz),
130.1, 129.6, 128.5, 128.2, 127.8, 127.4, 126.4, 125.6, 124.1 (d, J(P,C) =
7.3 Hz), 118.9, 117.8 ppm. 31P NMR (CD2Cl2,): d = 65.79 ppm (s,
1J(P,Seexo) = 822 Hz, 1J(P,Seendo) = 502Hz, 3J(P,P) = 4.7 Hz; lines for
2J(P,Seendo) were hidden under the intensive central line, prohibiting
calculation of the coupling constant). 77Se NMR (CD2Cl3): d = 498.94
(dd, 1J(P,Seendo) = 501 Hz, 2J(P,Seendo) = 23 Hz), 37.56 ppm (d, 1J-
(P,Seexo) = 820 Hz). EI+ MS m/z: 816 [M]+. Elemental analysis calcd
(%) for C32H22O2P2Se4: C 47.1, H 2.7; found C 46.3, H 2.6.
X-ray crystal data for compounds 1–5 were collected at 93 K using
a Rigaku MM007 high-brilliance RA generator/confocal optics and
Mercury CCD system. Intensities were corrected for Lorentz polar-
ization and for absorption. The structures were solved by direct
methods. Hydrogen atoms bound to carbon were idealized. Structural
refinements were obtained with full-matrix least-squares based on F2
using the program SHELXTL.[6] CCDC-663349 (1), 663350 (2),
663351 (3), 663352( 4), and 663353 (5) contain the supplementary
crystallographic data for this paper. These data can be obtained free
of charge from The Cambridge Crystallographic Data Centre via
www.ccdc.cam.ac.uk/data_request/cif.
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Angew. Chem. Int. Ed. 2008, 47, 2857 –2859
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