Allene-substituted-1,3,2-dioxaphospholanes in the reactions with sulfenyl bromides and selenenyl bromides

Article abstract of DOI:10.1080/10426501003757988

The reactivity of allene-substituted-1,3,2-dioxaphospholanes towards sulfenyl bromides and selenenyl bromides has been investigated, and 2,5-dihydro-1,2-oxaphosphole derivatives have been obtained. Taylor & Francis Group, LLC.

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Phosphorus, Sulfur, and Silicon and the
Related Elements
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Allene-Substituted-1,3,2-
Dioxaphospholanes in the Reactions
with Sulfenyl Bromides and Selenenyl
Bromides
Dobromir D. Enchev a
a Department of Organic Chemistry and Technology, Faculty of
Natural Sciences, Konstantin Preslavsky University, Shumen, Bulgaria
Published online: 19 Nov 2010.
To cite this article: Dobromir D. Enchev (2010) Allene-Substituted-1,3,2-Dioxaphospholanes in the
Reactions with Sulfenyl Bromides and Selenenyl Bromides, Phosphorus, Sulfur, and Silicon and the
Related Elements, 185:12, 2574-2578, DOI: 10.1080/10426501003757988
To link to this article: http://dx.doi.org/10.1080/10426501003757988
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Phosphorus, Sulfur, and Silicon, 185:2574–2578, 2010
Copyright ꢀC Taylor & Francis Group, LLC
ISSN: 1042-6507 print / 1563-5325 online
DOI: 10.1080/10426501003757988
ALLENE-SUBSTITUTED-1,3,2-DIOXAPHOSPHOLANES
IN THE REACTIONS WITH SULFENYL BROMIDES
AND SELENENYL BROMIDES
Dobromir D. Enchev
Department of Organic Chemistry and Technology, Faculty of Natural Sciences,
Konstantin Preslavsky University, Shumen, Bulgaria
The reactivity of allene-substituted-1,3,2-dioxaphospholanes towards sulfenyl bromides and
selenenyl bromides has been investigated, and 2,5-dihydro-1,2-oxaphosphole derivatives
have been obtained.
Keywords Allene-substituted-1,3,2-dioxaphospholanes; 2,5-dihydro-1,2-oxaphospholes;
heterocyclization
INTRODUCTION
Continuing our study on the reactivity of allenephosphonates towards sulfenyl
bromides and selenenyl bromides,1–3 we have investigated the allene-substituted-1,3,2-
dioxaphospholanes as substrates in the reaction with these reagents.
RESULTS AND DISCUSSION
The compounds 2a–c have been synthesized by the procedure described,4 i.e., by the
reaction of 1,2-alkadienephosphonic dichlorides 1a–c with 1,2-ethandiol. The reactions are
shown in Scheme 1.
The obtained allene-substituted-1,3,2-dioxaphospholanes 2a–c have been investi-
gated in the reactions with phenylsulfenyl bromides and phenylselenenyl bromides. In all
cases, regardless of the kind of the reagent employed, the 2,5-dihydro-1,2-oxaphosphole
derivatives were isolated. The reactions are shown in Scheme 2.
Our results reported here, and the results of others,5 show that regardless of the kind
of electrophilic reagent used, the reaction of these substrates leads to 1,2-oxaphosphole
derivatives 3a–d and 3e,f, respectively. We believe that the generation of 3a–d and 3e,f is
due to the formation of quasiphosphonium intermediate B (Scheme 3), which decomposes
under attack by the bromine anion. The formation of the intermediate B has been confirmed
by others.5
Received 18 January 2010; accepted 8 March 2010.
Address correspondence to Dobromir D. Enchev, Department of Organic Chemistry and Technology, Faculty
of Natural Sciences, Konstantin Preslavsky University, 115 “Universitetska” Str., BG 9712, Shumen, Bulgaria.
E-mail: enchev@shu-bg.net
2574

ALLENE-SUBSTITUTED-1,3,2-DIOXAPHOSPHOLANES
2575
HOCH2CH2OH
2C5H5N
Et2O, -8o to -5oC
R1
R2
R1
R2
O
O
- 2C5H5N.HCl
Cl2P
P
O
O
O
1a,b
2a,b
HOCH2CH2OH
2C5H5N
Et2O, -8o to -5oC
O
O
- 2C5H5N.HCl
Cl2P
P
O
1c
2c
R1 = R2 =Me, R1 = Me, R2 = Et, R1 + R2 =cyclohexyl
Scheme 1
YPh
R1
R2
R1
R2
O
PhYBr
CH2Cl2, 0o to -5oC
P
O
O
O
3a-d
O
P
Br
O
2a,b
R1 = R2 = Me, R1 = Me, R2 = Et, Y= S, Se
YPh
O
O
PhYBr
CH2Cl2, 0o to -5oC
O
P
O
3e,f
P
Br
O
O
2c
R1 + R2= cyclohexyl, Y= S, Se
Scheme 2
EXPERIMENTAL
1
The H NMR and 31P NMR spectra were measured at normal probe temperature
on a Bruker Avance DRX 250 MHz spectrometer using TMS as internal reference in
CDCl3 solutions. Chemical shifts are given in ppm and are downfield from the internal
standard. The IR spectra have been run on an IR-72 spectrophotometer (Carl Zeiss, Jena).
Elemental analyses have been carried out by the University of Shumen, Microanalytical
Service Laboratory.
Phenylselenenyl bromide is commercially available. Phenylsulfenyl bromide was
synthesized according to the procedure described.6 Melting points are uncorrected.
Compounds 1a–c were synthesized according to the procedure described.7
The solvents were purified by standard methods. All reactions were carried out in
oven-dried glassware under an argon atmosphere and with exclusion of moisture. All
compounds were checked for their purity on TLC plates.

2576
D. D. ENCHEV
R1
R2
YPh
YPh
PhYBr
O
O
R1
R2
R1
R2
O
O
P
P
P
O
O
O
O
O
2a-c
Br
A
B
YPh
YPh
R1
R2
R1
R2
O
O
O
P
P
Br
O
O
O
Br
3a-f
R1 = R2 = Me, R1 = Me, R2 = Et, R1 + R2 = cyclohexyl
Y = S, Se
Scheme 3
Preparation of Compounds 2a–c
To a solution of 5 mmol of the appropriate dichloride 1a–c in 50 mL of dry diethyl
ether at –8◦C to –5◦C with stirring, a mixture of 5 mmol (0.32 g) of 1,2-ethandiol and 10
mmol (0.79 g) of pyridine dissolved in 50 mL of diethyl ether was added. After 1 h of
stirring, the reaction mixture stood overnight. The precipitate was filtered off, the solvent
was removed under reduced pressure, and the residue was purified by chromatography with
ethyl acetate/hexane (1:1).
2-(3-Methylbuta-1,2-dienyl)-[1,3,2]dioxaphospholane-2-oxide
2a. Oil,
0.68 g, (79%), IR(KBr) νmax/cm−1 1989 (C C C), 1237 (P O), 900 (P-O-C); 1H NMR
2
(CDCl3) ppm: 5.35 (d, JHP = 7.75 Hz, 1 H, HC ); 4.40 (s, 4H, 2 CH2); 2.18 (s, 6H, 2
CH3); 31P NMR (CDCl3) ppm: 31P 17.0, Anal., Calcd. for C7H11O3P (Mr = 174.128): P
17.78%; Found: P 17.74%.
2-(3-Methylpenta-1,2-dienyl)-[1,3,2]dioxaphospholane-2-oxide 2b. Oil,
0.69 g, (74%), IR (KBr) νmax/cm−1 1990 (C C C), 1235 (P O), 900 (P-O-C); 1H NMR
2
(CDCl3): ppm 5.52 (d, JHP = 7.74 Hz, 1 H, HC ); 4.40 (s 4 H, 2 CH2); 2.00 (m, 2 H,
CH2CH3); 1.70 (t, 3 H, CCH3); 0.99 (t, 3H, CH2CH3); 31P NMR (CDCl3) ppm: 31P 17.0,
Anal., Calcd. for C8H13O3P (Mr = 188.154): P 16.46%; Found: P 16.43%.
2-(2-Cyclohelidenevinyl)-[1,3,2]dioxaphospholane-2-oxide 2c. Oil, 0.81 g,
(76%), IR (KBr) νmax/cm−1 1990 (C C C), 1235 (P O), 900 (P-O-C); 1H NMR (CDCl3):
2
ppm 5.71 (d, JHP = 7.68 Hz, 1 H, HC ); 4.40 (s, 4 H, 2CH2); 2.09 (m, 4 H, cyclo-
hexyl); 1.52–1.60 (m, 6 H cyclohexyl); 31P NMR (CDCl3) ppm: 31P 17.0, Anal., Calcd. for
C10H15O3P (Mr = 214.19): P 14.46%; Found: P 14.41%.
Preparation of Compounds 3a–f
To a solution of 5 mmol of 2a–c in 50 mL of methylene chloride at 0◦C to –5◦C, a
solution of 5 mmol (0.94 g) of phenylsulfenyl bromide or 5 mmol (1.18 g) of phenylsele-
nenyl bromide was added with stirring. After 1 h of stirring, the solvent was removed under
reduced pressure, and the residue was recrystallized in benzene/hexane (1:1).

ALLENE-SUBSTITUTED-1,3,2-DIOXAPHOSPHOLANES
2577
2-(2-Bromoethoxy)-5,5-dimethyl-4-phenylsulfenyl-5H-[1,2]oxaphosphole-
2-oxide 3a. Cryst., 1.39 g, (77%), mp 91–93◦C, IR (KBr) νmax/cm−1 1589 (C C), 1237
1
(P O), 900 (P-O-C); H NMR (CDCl3) ppm : 7.56–7.46 (m, 2 H, Ph); 7.29–7.23 (m, 3
2
H, Ph); 5.96 (d, JHP = 27.75 Hz, 1 H, HC ); 4.53 (q 2 H, BrCH2CH2O); 3.74 (t, 2 H,
BrCH2CH2O); 1.28 (s, 6 H, 2CH3); 31P NMR (CDCl3) ppm: 31P 29.1, Anal., Calcd. for
C13H16BrO3PS (Mr = 363.188): P 8.53, Br 22.00, S 8.83%; Found: P 8.50, Br 21.97, S
8.80.
2-(2-Bromoethoxy)-5-ethyl-5-methyl-4-phenylsulfenyl-5H-[1,2]oxaphosp
hole-2-oxide 3b. Cryst.,1.32 g, (70%), mp 95–98◦C, IR (KBr) νmax/cm−1 1589 (C C),
1
1237 (P O), 900 (P-O-C); H NMR (CDCl3) ppm : 7.56–7.46 (m, 2 H, Ph); 7.29–7.23
(m, 3 H, Ph); 5.96 (d, 2JHP = 26.75 Hz, 1 H, HC ); 4.50 (q 2 H, BrCH2CH2O); 3.64 (t, 2
H, BrCH2CH2O); 1.70 (q, 2 H, CH2CH3); 1.33 (s, 3 H, CCH3); 0.69 (t, 3 H, CH2CH3);
31P NMR (CDCl3) ppm: 31P 28.0, Anal., Calcd. for C14H18BrO3PS (Mr = 377.214): P
8.21, Br 21.18, S 8.50%; Found: P 8.19, Br 21.12, S 8.47.
2-(2-Bromoethoxy)-4-phenylsulfenyl-1-oxa-2-phosphaspyro-[4,5]dec-3-
ene-2-oxide 3c. Cryst., 1.51 g, (75%), mp 101–103◦C, IR (KBr) νmax/cm−1 1589
1
(C C), 1237 (P O), 900 (P-O-C); H NMR (CDCl3) ppm : 7.56–7.46 (m, 2 H, Ph);
7.29–7.23 (m, 3 H, Ph); 5.61 (d, 2JHP = 27.70 Hz, 1 H, HC ); 4.42 (q 2 H, BrCH2CH2O);
3.55 (t, 2 H, BrCH2CH2O); 1.43–1.90 (m, 10 H, cyclohexyl); 31P NMR (CDCl3) ppm: 31
P
28.7, Anal., Calcd. for C16H20BrO3PS (Mr = 403.25): P 7.68, Br 19.81, S 7.95%; Found:
P 7.66, Br 19.78, S 7.91;
2-(2-Bromoethoxy)-5,5-dimethyl-4-phenylselenenyl-5H-[1,2]oxaphosph
ole-2-oxide 3d. Cryst., 1.59 g, (78%), mp 90–92◦C, IR (KBr) νmax/cm−1 1589 (C C),
1
1237 (P O), 900 (P-O-C); H NMR (CDCl3) ppm : 7.56–7.46 (m, 2 H, Ph); 7.29–7.23
(m, 3 H, Ph); 5.96 (d, 2JHP = 27.75 Hz, 1 H, HC ); 4.58 (q 2 H, BrCH2CH2O); 3.44 (t, 2
H, BrCH2CH2O); 1.28 (s, 6 H, 2CH3); 31P NMR (CDCl3) ppm: 31P 29.0, Anal., Calcd. for
C13H16BrO3PSe (Mr = 410.088) : P 7.55, Br 19.48%; Found: P 7.50, Br 19.43.
2-(2-Bromoethoxy)-5-ethyl-5-methyl-4-phenylselenenyl-5H-[1,2]oxapho
sphole-2-oxide 3e. Cryst., 1.5 g, (71%), mp 95–98◦C, IR (KBr) νmax/cm−1 1589
1
(C C), 1237 (P O), 900 (P-O-C); H NMR (CDCl3) ppm : 7.56–7.46 (m, 2 H, Ph);
7.29–7.23 (m, 3 H, Ph); 5.96 (d, 2JHP = 28.70 Hz, 1 H, HC ); 4.53 (q 2 H, BrCH2CH2O);
3.74 (t, 2 H, BrCH2CH2O); 1.70 (q, 2 H, CH2CH3); 1.33 (s, 3 H, CCH3); 0.69 (t, 3 H,
CH2CH3); 31P NMR (CDCl3) ppm: 31P 29.0, Anal., Calcd. for C14H18BrO3PSe (Mr =
424.114): P 7.30, Br 18.84%; Found: P 7.26, Br 18.80.
2-(2-Bromoethoxy)-4-phenylselenenyll-1-oxa-2-phosphaspyro-[4,5]dec-
3-ene-2-oxide 3f. Cryst., 1.62 g, (72%), mp 105–108◦C, IR (KBr) νmax/cm−1 1589
1
(C C), 1237 (P O), 900 (P-O-C); H NMR (CDCl3) ppm : 7.56–7.46 (m, 2 H, Ph);
7.29–7.23 (m, 3 H, Ph); 5.61 (d, 2JHP = 26.65 Hz, 1 H, HC ); 4.50 (q 2 H, BrCH2CH2O);
3.70 (t, 2 H, BrCH2CH2O); 1.43–1.90 (m, 10 H, cyclohexyl); 31P NMR (CDCl3) ppm: 31
P
26.0, Anal., Calcd. for C16H20BrO3PSe(Mr = 450.15): P 6.88, Br 17.75%; Found: P 6.86,
Br 17.70.
REFERENCES
1. D. D. Enchev, Phosphorus, Sulfur, and Silicon, 180, 2211 (2005).
2. D. D. Enchev, Heteroatom Chem., 16, 156 (2005).
3. D. D. Enchev and S. P. Stankolov, Phosphorus, Sulfur, and Silicon, 182, 1857 (2007).

2578
D. D. ENCHEV
4. Ch. M. Angelov, T. S. Mikhailova, V. M. Ignatiev, V. I. Zakharov, A. V. Dogadina, B. I. Ionin,
and A. A. Petrov, Zh. Obsch. Khim., 49, 1487 (1977).
5. Ch. M. Angelov and Ch. Zh. Christov, Heterocycles, 20, 219 (1983).
6. H. Lecher and F. Holschneider, Ber., 57, 755 (1924).
7. M. P. Simonin, M. J. Pauet, J. M. Gence, and C. Paumier, Org. Magn. Reson., 8, 508 (1976).