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DOI: 10.1055/s-0031-1290349
Small Organophosphorus-Selenium Heterocycles from the Selenation of Conjugated Ketones and Enals
Publication History
Publication Date:
10 February 2012 (online)
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Abstract
Reaction of 2,4-bis(phenyl)-1,3-diselenadiphosphetane-2,4-diselenide [Woollins’ reagent, WR] with equimolar amount of α,β-unsaturated ketones [R¹C(O)C=CR² (R¹ = aryl or alkyl; R² = aryl)] leads to a series of novel five-membered C3P(Se)Se heterocycles 1-8 in 48-95% isolated yields. Furthermore, WR reacts with one equivalent of aromatic conjugated enals [RC=CC=O, R = Ph and 2-MeOC6H4] to give five-membered C3P(Se)Se heterocycles 9 and 10 via the cleavage/cyclic extension of WR molecular ring. All new compounds have been characterised spectroscopically (³¹P NMR, 77Se NMR, ¹H NMR, ¹³C NMR, IR and mass spectroscopy) and one representative X-ray structure is reported.
Key words
selenium - phosphorus - heterocycles - Woollins’ reagent - X-Ray structure
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References and Notes
Crystallographic Data for Compound 1a: C21H17PSe2, M = 458.24, monoclinic, space group P21/n, a = 9.948 (3), b = 16.347 (7), c = 11.640 (4) Å, β = 102.399 (8)˚, U = 1848.7 (11) ų, Z = 4, µ = 1.646 mm-¹, 12616 reflections, 3627 unique (R int = 0.038); R 1 = 0.044, wR 2 = 0.106.
24Experimental Section: Unless otherwise
stated, all reactions were carried out under an oxygen-free nitrogen
atmosphere using pre-dried solvents and standard Schlenk techniques, subsequent
chromatographic and workup procedures were performed in air. ¹H
NMR (270 MHz), ¹³C NMR (67.9 MHz), ³¹P-{¹H} NMR
(109 MHz) and 77Se-{¹H} (51.4
MHz referenced to external Me2Se) NMR spectra were recorded at
25 ˚C (unless stated otherwise) on a JEOL GSX 270 spectrometer.
IR spectra were recorded as KBr pellets in the range of 4000-250
cm-¹ on a Perkin-Elmer 2000
FTIR/Raman spectrometer. Microanalysis was performed by
the University of St-Andrews microanalysis service. Mass spectrometry
was performed by the EPSRC National Mass Spectrometry Service Centre,
Swansea and the University of St Andrews Mass Spectrometry Service.
X-ray crystal data for 1, were collected
using a Rigaku SCXMIni Mercury CCD system. Intensity data were collected
using ω steps accumulating area detector images spanning
at least a hemisphere of reciprocal space. The data were corrected
for
Lorentz polarisation effects. Absorption effects were corrected
on the basis of multiple equivalent reflections or by semi-empirical
methods. Structures were solved by direct methods and refined by
full-matrix least-squares against F² by using
the program SHELXTL.²5 Hydrogen atoms were assigned
riding isotropic displacement parameters and constrained to idealised
geometries. The data (CCDC 855701) can be obtained free of charge
via www.ccdc.cam.ac.uk/conts/retrieving.html or
from the Cambridge Crystallographic Data centre, 12 Union Road, Cambridge
CB2 1EZ, UK; fax +44(1223)336033; e-mail: deposit@ccdc.cam.ac.uk.
General Procedure for Synthesis of Compounds
1-8 from the Selenation of α
,
β-Unsaturated
Ketones: A mixture of α,β-unsaturated ketone
(1.0 mmol) and WR (0.54 g, 1.0 mmol) in
anhyd toluene (20 mL) was refluxed for 7 h. Red suspension disappeared
and a pale brown solution was formed along with small amount of
grey elemental selenium precipitate. Upon cooling to r.t. and removing
the unreacted solid by filtration the filtrate was dried in evaporator
and purified by silica gel column (eluent: EtOAc-CH2Cl2,
1:1) to give compounds 1-8.
Compound
1: yellow paste (425 mg) in 92% isolated yield. IR
(KBr): 1599 (m, C=C), 1490 (m), 1434 (m), 1088 (m), 749
(s), 690 (s), 595 (m), 513 (m) cm-¹.
A pair of stereoisomers was found in ca. 4:6 intensity ratio. ¹H
NMR (CD2Cl2): δ = 8.21 (dd,
2 × 4 H, ArH), 7.01-7.59 (m, 2 × 10 H,
ArH), 6.65 (dd, J
H,H = 3.6
Hz, J
P,H = 32.2 Hz,
1 H, HC=C), 6.57 (dd, J
H,H = 3.6
Hz, J
P,H = 32.2 Hz,
1 H, HC=C), 5.52 (dd, J
H,H = 3.6
Hz, J
P,H = 18.2 Hz,
1 H, HC), 5.09 (dd, J
H,H = 3.6 Hz, J
P,H = 18.2 Hz, 1
H, HC). ¹³C NMR (CD2Cl2): δ = 142.3, 142.0,
141.8, 141.7, 136.1, 134.6, 134.1, 134.0, 133.1, 132.9, 132.8, 132.4,
132.1, 131.8, 131.7, 129.4, 129.0, 129.0, 128.8, 128.6, 128.5, 128.3,
128.2, 128.0, 127.9, 127.8, 127.3, 127.2, 125.4, 124.9, 71.6 (d, J
P,C = 30.1 Hz), 65.8
(d, J
P,C = 29.1 Hz). ³¹P
NMR (CD2Cl2): δ = 72.4 (s,
J
P-Se = 346
Hz, J
P=Se = 806
Hz), 71.4 (s, J
P-Se = 346
Hz,
J
P=Se = 786
Hz). 77Se NMR (CD2Cl2): δ = 408.9
(d, J
P-Se = 346
Hz), 391.5 (d, J
P-Se = 346
Hz), -170.8 (d, J
P=Se = 786 Hz), -187.5
(d, J
P=Se = 806
Hz). MS (ESI+): m/z = 483 [M + Na]+.
MS (CI+): m/z = 461 [M + H]+.
HRMS (CI+): m/z [M + H]+ calcd
for C21H18PSe2: 460.9471; found:
460.9473.
Compound 2: yellowish
milky solid (466 mg) in 95% isolated yield. IR (KBr): 1607
(m, C=C), 1510 (s, C=C), 1435 (m), 1303 (m), 1251
(s), 1177 (m), 1090 (m), 1030 (m), 831 (m), 746 (m), 688 (m), 596
(m), 521 (m) cm-¹. A pair of stereoisomers
was found in ca. 4:6 intensity ratio. ¹H NMR (CD2Cl2): δ = 8.22
(dd, J
H,H = 6.9 Hz,
2 × 4 H, ArH), 6.92-7.75 (m, 2 × 10 H,
ArH), 6.65 (dd, 2 × 1 H, HC=C), 5.45 (dd,
J
P,H = 17.6
Hz, 2 × 1H, HC), 3.80 (s, 3 H, OMe), 3.69 (s, 3 H, OMe). ¹³C
NMR (CD2Cl2): δ = 141.8,
141.7, 141.4, 141.3, 136.2, 133.2, 133.0, 132.4 (d, J
P,C = 3.1 Hz), 132.2
(d, J
P,C = 3.1 Hz),
131.9, 131.7, 130.6, 130.5, 129.5, 129.4, 129.1, 129.0, 128.9, 128.7,
128.1, 127.9, 127.4, 127.3, 125.8, 125.3, 71.0 (d, J
P,C = 31.1
Hz), 65.2 (d, J
P,C = 29.1 Hz),
55.3. ³¹P NMR (CD2Cl2): δ = 73.0
(s, J
P-Se = 336
Hz, J
P=Se = 801
Hz), 71.6 (s, J
P-Se = 345
Hz, J
P=Se = 784
Hz). 77Se NMR (CD2Cl2): δ = 406.7
(d, J
P-Se = 336
Hz), 390.0 (d, J
P-Se = 345
Hz), -174.1 (d, J
P=Se = 784
Hz), -188.2 (d, J
P=Se = 801 Hz).
MS (CI+): m/z = 491 [M + H]+.
HRMS (CI+): m/z [M + H]+ calcd
for C22H20OPSe2: 490.9577; found:
490.9582.
Compound 3: pale yellow
paste (320 mg) in 81% isolated yield. IR (KBr): 1555 (w,
C=C), 1489 (m), 1433 (m), 1090 (m), 764 (m), 745 (m), 689
(s), 558 (m), 526 (m), 505 (m) cm-¹. Four stereoisomers
were found in ca. 4:4:2:2 intensity ratio. ¹H
NMR (CD2Cl2): δ = 7.98-8.19
(m, 4 × 2 H, ArH), 6.91-7.64 (m, 4 × 8
H, ArH), 6.38-6.63 (m, 4 × 1 H, CH), 5.92-6.19
(m, 4 × 1 H, CH), 2.32-2.34 (s, 4 × 3
H, Me).
¹³C NMR (CD2Cl2): δ = 141.3,
141.1, 140.0, 139.9, 138.3, 138.2, 134.5, 134.4, 133.1, 132.9, 132.4,
132.3, 132.0, 131.7, 131.5, 129.4, 129.3, 129.1, 128.8, 128.7, 128.6, 128.4,
128.2, 128.1, 128.0, 127.9, 127.7, 125.3, 71.2, 70.8, 65.3, 64.9,
21.9, 21.2. ³¹P NMR (CD2Cl2): δ = 75.6
(s,
J
P-Se = 390
Hz, J
P=Se = 765
Hz), 75.3 (s, J
P-Se = 336
Hz, J
P=Se = 801
Hz), 74.7 (s, J
P-Se = 346
Hz, J
P=Se = 782
Hz), 61.7 (s,
J
P-Se = 390
Hz, J
P=Se = 770
Hz). 77Se NMR (CD2Cl2): δ = 449.7
(d, J
P-Se = 390
Hz), 443.9 (d, J
P-Se = 390
Hz), 421.4 (d, J
P-Se = 336
Hz), 405.5 (d, J
P-Se = 346
Hz), -111.7 (d, J
P=Se = 770
Hz), -125.9 (d, J
P=Se = 765
Hz), -156.7 (d, J
P=Se = 782 Hz), -182.8
(d, J
P=Se = 801
Hz). MS (EI+): m/z = 398 [M]+. HRMS
(EI+): m/z [M]+ calcd
for C16H15P76Se2: 389.9290; found:
389.99293.
Compound 4: orange
solid (414 mg) in 84% isolated yield. IR (KBr): 1601 (m,
C=C), 1505 (vs, C=C), 1434 (s), 1224 (s), 1158
(m), 1090 (m), 834 (s), 745 (s), 687 (m), 526 (m), 508 (s) cm-¹.
A pair of stereoisomers was found in ca. 1:2 intensity ratio. ¹H
NMR (CD2Cl2): δ = 8.14-8.
22 (d, J
H,H = 7.2
Hz, 2 × 2 H, ArH), 6.74-7.69 (m, 2 × 11
H, ArH), 6.40-6.52 (d, 2 × 1 H, CH), 5.44-5.50
(d, 2 × 1 H, CH), 2.38 (s, 3 H, Me), 2.37 (s, 3 H, Me). ¹³C
NMR (CD2Cl2): δ = 164.6, 164.3,
161.0, 160.8, 140.0, 133.1, 132.9, 132.5, 132.3, 131.8, 131.6, 131.0,
130.3, 129.9, 129.7, 129.1, 128.8, 128.6, 128.5, 128.1, 127.9, 127.6,
127.2, 127.1, 124.1, 123.8, 70.9, 70.5, 65.1, 64.6, 21.1, 21.0. ³¹P
NMR (CD2Cl2): δ = 72.0 (s, J
P-Se = 340
Hz, J
P=Se = 803
Hz), 70.7 (s, J
P-Se = 357
Hz, J
P=Se = 789
Hz). 77Se NMR (CD2Cl2): δ = 400.7
(d, J
P-Se = 340
Hz), 386.5 (d, J
P-Se = 357
Hz), -177.8 (d, J
P=Se = 789
Hz), -191.1 (d, J
P=Se = 803
Hz). MS (CI+): m/z = 493
[M + H]+.
MS (EI+) m/z = 492 [M]+.
HRMS (EI+): m/z [M]+ calcd
for C22H18FP76Se2: 483.9509;
found: 483.9504.
Compound 5: yellow
solid (403 mg) in 83% isolated yield. Two stereoisomers
were found in ca. 1:2 intensity ratio. IR (KBr): 1598 (w, C=C),
1491 (m, C=C), 1434 (m, C=C), 1185 (w), 1165 (w),
1128 (w), 1088 (s), 939 (s), 764 (s), 745 (s), 688(vs), 630 (m),
595 (s), 506 (s, P=Se) cm-¹. ¹H
NMR (CDCl3): δ = 7.47-7.63
(m, 2 × 2 H, ArH), 7.30-7.37 (m, 2 × 5
H, ArH), 7.12-7.21 (m, 2 × 4 H, ArH), 7.04-7.11
(m, 2 × 4 H, ArH), 6.93-6.96 (m, 2 × 2
H, ArH), 7.05 (d, J = 3.0 Hz,
1 H, CH), 6.95 (d, J = 3.0 Hz,
1 H, CH), 6.66 (dd,
³
J
H,H = 3.0
Hz, ³
J
P,H = 15.0
Hz, 1 H, CH), 6.36 (dd,
³
J
H,H = 3.0 Hz, ²
J
P,H = 32.0 Hz, 1
H, CH). ¹³C NMR (CDCl3): δ = 141.0,
136.0, 135.8, 133.1, 133.0, 132.6, 132.4, 132.0, 129.0, 128.8, 128.3,
128.2, 127.9, 127.8, 127.0, 125.2, 70.3 (d, ¹
J
P,C = 29 Hz). ³¹P
NMR (CDCl3): δ = 70.3 (s, J
P-Se = 338 Hz, J
P=Se = 803
Hz), 69.9 (s, J
P-Se = 350
Hz, J
P=Se = 782
Hz). 77Se NMR (CDCl3): δ = 374.0
(d, J
P-Se = 338
Hz), 354.9 (d, J
P-Se = 350
Hz), -170.7 (d, J
P=Se = 782
Hz), -188.0 (d,
J
P=Se = 803
Hz). MS (ES+): m/z = 507 [M + Na]+.
Anal. Calcd for C23H19PSe2 (484.29):
C, 57.04; H, 3.95. Found: C, 57.01; H, 3.99.
Compound 6: brown solid (340 mg) in 67% yield. ³¹P
NMR spectrum revealed four stereoisomers in ca. 4:2:1:2 intensity ratio.
IR (KBr): 1691 (m, C=C), 1594 (m, C=C), 1518 (s, C=C),
1434 (m), 1343 (s), 1089 (m), 851 (s), 689 (s), 596 (m), 508 cm-¹. ¹H
NMR (CD2Cl2): δ = 7.54-8.30
(m, 4 × 10 H, thienyl-H, ArH), 7.00-7.32 (m, 2
H, thienyl-H), 6.75-6.93 (m, 4 × 1 H, =CH),
3.26-3.44 (m, 4 × 1 H, SeCH).
¹³C
NMR (CD2Cl2): δ = 150.4,
148.0, 147.7, 147.3, 143.5,142.1, 141.2, 139.2, 133.1, 133.0, 132.9,
132.7, 132.5, 132.0, 131.8, 129.1, 128.9, 128.8, 128.7, 128.6, 128.3, 128.1,
127.9, 127.8, 127.4, 127.1, 125.0, 124.6, 124.2, 123.9, 123.6, 67.6,
67.1, 61.8, 61.4, 41.1, 23.9. ³¹P NMR (CD2Cl2): δ = 73.7
(s, J
P-Se = 331
Hz, J
P=Se = 832
Hz), 71.8 (s, J
P-Se = 340
Hz, J
P=Se = 796
Hz), 61.0 (s, J
P-Se = 366
Hz, J
P=Se = 793
Hz), 54.1 (s, J
P-Se = 380
Hz, J
P=Se = 782
Hz). 77Se NMR (CD2Cl2): δ = 487.1
(d, J
P-Se = 381
Hz), 473.1 (d, J
P-Se = 365
Hz), 414.8 (d, J
P-Se = 329
Hz), 405.6 (d, J
P-Se = 341 Hz), -83.2
(d, J
P=Se = 782
Hz), -161.5 (d, J
P=Se = 793
Hz),
-166.7 (d, J
P=Se = 796
Hz), -190.8 (d, J
P=Se = 832
Hz). MS (EI+): m/z = 511 [M]+.
HRMS (EI+): m/z [M]+ calcd
for C19H14O2NPS74Se2:
498.8927; found: 498.8933.
Compound
7: dark red solid (250 mg)in 50% yield.
³¹P
NMR spectrum revealed two stereoisomers in ca. 3:1 intensity ratio.
IR (KBr): 1634 (s, C=C), 1557 (m, C=C), 1539 (m,
C=C), 1470 (s), 1435 (m), 1408 (m), 1220 (m), 1071 (m),
781 (m), 748 (m), 686 (s)cm-¹. ¹H
NMR (CD2Cl2): δ = 6.96-8.15
(m, 2 × 9 H, ArH), 6.41 (d, J
P,H = 16.5
Hz, 1 H, CH), 6.40 (d, J
P,H =16.5
Hz, 1 H, CH), 3.77-4.04 (m, 2 × 1 H, CH), 3.37
(s, 6 H, Me), 2.94 (s, 6 H, Me). ¹³C
NMR (CD2Cl2): δ = 142.6,
140.5, 138.2, 134.8, 132.7, 132.5, 132.3, 132.0, 131.4, 131.2, 130.2,
130.0, 128.8, 128.6, 127.2, 126.1, 61.1, 56.6, 37.1, 34.1. ³¹P
NMR (CD2Cl2): δ = 57.0 (s, J
P-Se = 333
Hz, J
P=Se = 787
Hz), 56.1 (s, J
P-Se = 369 Hz, J
P=Se = 785
Hz). 77Se NMR (CD2Cl2): δ = 455.2
(d, J
P-Se = 369
Hz), 450.0 (d, J
P-Se = 333
Hz), -131.2 (d, J
P=Se = 785 Hz), -131.6
(d, J
P=Se = 787
Hz). MS (EI+): m/z = 505 [M]+. HRMS
(EI+): m/z [M]+ calcd
for C17H17BrPSe2: 504.8612; found:
504.8615.
Compound 8: pale yellow
solid (224 mg) in 48% yield. Multi-NMR spectrum revealed
four stereoisomers in ca. 3:4:2:2 extensity ratio. IR (KBr): 1657
(s, C=C), 1432 (s), 1226 (m), 1089 (s), 819 (m), 699(vs),
595 (m), 507 (s) cm-¹. ¹H
NMR (CD2Cl2): δ = 8.22-7.01
(m, 4 × 9 H, thienyl-H + ArH), 6.65-6.94
(m, 4 × 2 H, thienyl-H), 5.65-5.75 (m, 4 × 1
H, =CH), 3.29-3.29 (m, 4 × 1 H, SeCH). ¹³C
NMR (CD2Cl2): δ = 144.2,
143.8, 143.6, 143.2, 138.9, 136.1, 135.2, 134.6, 133.7, 133.6, 133.0,
132.9, 132.7, 132.5, 132.4, 132.1, 131.7, 128.8, 128.3, 128.2, 128.0,
127.9, 127.3, 126.9, 125.2, 125.1, 123.7, 123.5, 44.5, 43.8, 43.3, 41.0. ³¹P
NMR (CD2Cl2): δ = 71.1 (s, J
P-Se = 336
Hz, J
P=Se = 810
Hz), 69.1 (s, J
P-Se = 341
Hz, J
P=Se = 792
Hz), 61.0 (s,
J
P-Se = 377
Hz, J
P=Se = 789
Hz), 60.5 (s, J
P-Se = 393
Hz, J
P=Se = 777
Hz). 77Se NMR (CD2Cl2): δ = 477.2
(d, J
P-Se = 377 Hz),
412.7 (d, J
P-Se = 341
Hz), 407.3 (d, J
P-Se = 336
Hz), 398.5 (d, J
P-Se = 393
Hz), -142.5 (d, J
P=Se = 777
Hz), -166.4 (d, J
P=Se = 789
Hz), -176.7 (d, J
P=Se = 792
Hz), -203.3 (d, J
P=Se = 810
Hz). MS (EI+): m/z = 472 [M]+.
HRMS (EI+):
m/z [M]+ calcd
for C17H13PS2
74Se2:
459.8640; found: 459.8635.
General
Procedure for Synthesis of Compounds 9 and 10 from the Selenation
of Aromatic α,β-Unsaturated Enals: A red
solution of aromatic enal (1.0 mmol) and WR (0.54
g, 1.0 mmol) in anhyd toluene (20 mL) was refluxed for 7 h. Red
suspension disappeared and a pale brown solution along with small
amount of grey elemental selenium precipitate was formed. Upon cooling
to r.t. the mixture was dried in evaporator and the residue was
purified by silica gel column (eluent: EtOAc-CH2Cl2,
1:5) to give compounds 9 and 10.
Compound
9: reddish yellow paste (600 mg) in 79% isolated yield. ³¹P
NMR spectrum revealed a mixture of four stereoisomers in ca. 5:7:5:3
intensity ratio. IR (KBr): 1673 (s, C=C), 1491 (m), 1450
(m), 1434 (m), 1121 (m), 1088 (m), 961 (m), 764(vs), 693(vs), 591
(m), 511 (m)cm-¹. ¹H NMR
(CD2Cl2): δ = 7.92-8.11
(m, 2 H, ArH), 7.07-7.58 (m, 8 H, ArH), 6.84-6.96
(m, 1 H, CH), 6.58-6.66 (m, 1 H, CH), 6.11-6.16
(m, 1 H, CH). ¹³C NMR (CD2Cl2): δ = 137.0, 136.7,
134.0, 133.5, 133.4, 132.4, 132.2, 132.0, 131.6, 130.7, 129.6, 129.5,
129.0, 128.9, 128.7, 128.6, 128.4, 128.2, 128.1, 127.9, 127.5, 126.6,
32.0. ³¹P NMR (CD2Cl2): δ = 72.6
(s, J
P-Se = 326
Hz, J
P=Se = 802
Hz), 72.1 (s, J
P-Se = 336
Hz, J
P=Se = 784
Hz), 55.6 (s, J
P-Se = 383
Hz, J
P=Se = 770 Hz),
55.5 (s, J
P-Se = 383
Hz, J
P=Se = 767
Hz). MS (CI+):
m/z = 385 [M + H]+.
HRMS (CI+): m/z [M + H]+ calcd
for C15H14PSe2: 384.9160; found:
384.9159.
Compound 10: greyish
yellow solid (230 mg) in 56% isolated yield. ³¹P
NMR spectrum revealed a pair of stereoisomers in ca. 1:2 intensity
ratio. IR (KBr): 1597 (m, C=C), 1490 (s), 1460 (s), 1434
(m), 1244(vs), 1026 (m), 750 (s) cm-¹. ¹H
NMR (CD2Cl2): δ = 7.02-8.20
(m, 2 × 6 H, thienyl-H + ArH), 6.83-6.99
(m, 2 × 3 H, thienyl-H), 6.37-6.51 (m, 2 × 1
H, =CH), 5.38-5.44 (m, 2 × 1 H, PCH),
3.87 (s, 3 H, OMe), 3.80 (s, 3 H, OMe), 3.29-3.45 (m, 2 × 1
H, SeCH). ¹³C NMR (CD2Cl2): δ = 157.4,
156.5, 148.0, 146.0, 133.7, 133.6, 132.0, 131.9, 131.7, 131.5, 129.7,
129.4, 129.3, 129.2, 129.1, 128.5, 128.3, 128.0, 127.9, 127.4, 127.3,
127.2, 127.0, 58.1, 57.6, 55.6, 55.5. ³¹P
NMR (CD2Cl2): δ = 71.9 (s, J
P-Se = 322
Hz, J
P=Se = 798
Hz), 75.1 (s, J
P-Se = 315
Hz, J
P=Se = 782
Hz). 77Se NMR (CD2Cl2): δ = 410.8
(d, J
P-Se = 322
Hz), 381.6 (d, J
P-Se = 315
Hz), -91.4 (d, J
P=Se = 782
Hz), -183.8 (d, J
P=Se = 798
Hz). MS (CI+): m/z = 415 [M + H]+.
HRMS (CI+): m/z [M + H]+ calcd
for C16H16OPSe2: 414.9265; found:
414.9264.