Iodine-catalyzed efficient hydrophosphonylation of N-tosyl aldimines

Article abstract of DOI:10.1021/jo9003162

(Chemical Equation Presented) Treatment of N-tosyl aldimines with dialkyl trimethylsilyl phosphites at 0°C in the presence of iodine as a catalyst afforded the corresponding sulfonamide phosphonates in excellent yields within 1.5 to 2.5 h.

Full text of DOI:10.1021/jo9003162

SCHEME 1. Synthesis of r-Aminophosphonates from
N-Tosyl Aldimines
Iodine-Catalyzed Efficient Hydrophosphonylation
of N-Tosyl Aldimines†
Biswanath Das,* Penagaluri Balasubramanyam,
Maddeboina Krishnaiah, Boyapati Veeranjaneyulu, and
Gandolla Chinna Reddy
Organic Chemistry DiVision-1, Indian Institute of Chemical
Technology, Hyderabad 500 007, India
TABLE 1. Reaction of N-Tosyl Benzaldimine with Various
biswanathdas@yahoo.com
Phosphites in the Presence of Different Lewis Acid Catalystsa
entry
1
phosphite
catalyst
time (h)
yield (%)b
ReceiVed February 12, 2009
Me3SiOP(OMe)2
I2
1.5
2.5
3.0
1.5
2.5
3.0
2.0
3.0
3.5
2.0
2.5
3.0
2.0
2.5
3.5
2.0
2.5
3.0
93
83
81
94
85
80
FeCl3
ZrCl4
I2
FeCl3
ZrCl4
I2
FeCl3
ZrCl4
I2
FeCl3
ZrCl4
I2
FeCl3
ZrCl4
I2
FeCl3
ZrCl4
2
3
4
5
6
Me3SiOP(OEt)2
HP(O)(OMe)2
HP(O)(OEt)2
P(OMe)3
NRc
NRc
NRc
NRc
NRc
NRc
NRc
NRc
NRc
NRc
NRc
NRc
Treatment of N-tosyl aldimines with dialkyl trimethylsilyl
phosphites at 0 °C in the presence of iodine as a catalyst
afforded the corresponding sulfonamide phosphonates in
excellent yields within 1.5 to 2.5 h.
P(OEt)3
a Reaction conditions: N-tosyl aldimine (1.0 mmol), phosphite (1.3
mmol), catalyst (20 mol %), DCM (2 mL), 0 °C, N2 atmosphere.
b Isolated yield. c No reaction.
R-Aminophosphonates and their derivatives possess various
important biological properties including antifungal, antibacte-
rial, and herbicidal activities.1 They are also inhibitors of a
variety of enzymes.2 Additionally they are useful as fire
retardants for cotton.1a A few methods have been developed
for the synthesis of these compounds at high temperatures or
by using some catalysts.1a,3 Recently some research groups have
accomplished the synthesis of these compounds in optically
active forms.1b,2,4
N-sulfonyl aldimines with dialkyl trimethylsilyl phosphites in
the presence of iodine as a catalyst at 0 °C (Scheme 1).
Initially the reaction of N-tosyl benzaldimine with different
phosphites in the presence of various catalysts was thoroughly
studied. Alkyl phosphites (e.g., (MeO)3P, (EtO)3P, (MeO)2-
P(O)H, (EtO)2P(O)H) afforded no products in the presence of
iodine after 2 h. The reaction was conducted at 0 °C to room
temperature. However, the reaction with dialkyl trimethylsilyl
phosphites underwent smoothly at 0 °C within 1.5 h to furnish
the corresponding sulfonamide phosphonates in excellent yields
(Table 1). These silyl phosphites are commercially available
and have been used here for the first time for hydrophospho-
nylation of aldimines.
Besides iodine various other catalysts were also utilized to
carry out the reaction. However, considering the reaction time
and yield iodine was preferred (Table 1).
Finally a series of sulfonamide phosphonates were prepared
(Table 2) from different N-tosyl aldimines6 derived from various
aromatic, heteroaromatic, and aliphatic aldehydes, using dialkyl
In continuation of our work5 on the development of useful
synthetic methodologies we have observed that sulfonamide
phosphonates can efficiently be synthesized by treatment of
† Part 186 in the series Studies on Novel Synthetic Methodologies.
(1) (a) Birum, G. H. U.S. patent 4. 032, 601, 1977; Chem. Abstr. 1977, 87,
135933. (b) Allen, J. G.; Atherton, F. R.; Hall, M. J.; Hassall, C. H.; Holmes,
S. W.; Lambert, R. W.; Nisbet, L. J.; Ringrose, P. S. Nature 1978, 272, 56. (c)
Abell, J. P.; Yamamoto, H. J. Am. Chem. Soc. 2008, 130, 10521. (d)
Aminophosphonic and Aminophosphinic Acids: Chemistry and Biological
ActiVities; Kukhar, V. P., Hudson, H. R., Eds.; Wiley & Sons: New York, 2000.
(2) (a) Smith, A. B., III; Yager, K. M.; Taylor, C. M. J. Am. Chem. Soc.
1995, 117, 10879. (b) Wiemer, D. F. Tetrahedron 1997, 53, 16609.
(3) (a) Varaprasad, L. V. S.; Jaiswal, D. K. Indian J. Chem. 1982, 21B, 525.
(b) Bhagat, S.; Chakraborti, A. K. J. Org. Chem. 2007, 72, 1263. (c) Changtao,
Q.; Taisheng, H. J. Org. Chem. 1998, 63, 4125. (d) Ranu, B. C.; Hajra, A.;
Jana, U. Org. Lett. 1999, 1, 1141. (e) Manabe, K.; Kobayashi, S. Chem. Commun.
2000, 669.
(4) (a) Sasai, H.; Arai, S.; Tahara, H.; Shibasaki, M. J. Org. Chem. 1995,
60, 6656. (b) Joly, G. D.; Jacobsen, E. N. J. Am. Chem. Soc. 2004, 126, 4102.
(c) Kobayashi, S.; Kiyohara, H.; Nakamura, Y.; Matsubara, R. J. Am. Chem.
Soc. 2004, 126, 6558. (d) Pawar, V. D.; Bettigeri, S.; Weng, S.-S.; Kao, J.-Q.;
Chen, C.-T. J. Am. Chem. Soc. 2006, 128, 6308. (e) Saito, B.; Egami, H.; Katsuki,
T. J. Am. Chem. Soc 2007, 129, 1978, and references cited therein.
(5) (a) Das, B.; Krishnaiah, M.; Balasubramanyam, P.; Veeranjaneyulu, B.;
Kumar, D. N. Tetrahedron Lett. 2008, 49, 2225. (b) Das, B.; Suneel, K.;
Venkateswarlu, K.; Ravikanth, B. Chem. Pharm. Bull. 2008, 56, 366. (c) Das,
B.; Krishnaiah, M.; Laxminarayana, K.; Suneel, K.; Kumar, D. N. Chem. Lett.
2009, 38, 42.
(6) (a) Jennings, W. B.; Lovely, C. J. Tetrahedron 1991, 47, 5561. (b) Love,
B. E.; Raje, P. S.; Williams, T. C., III Synlett 1994, 493. (c) Chemla, F.; Hebbe,
V.; Normant, J.-F. Synthesis 2000, 75.
10.1021/jo9003162 CCC: $40.75
Published on Web 04/27/2009
2009 American Chemical Society
J. Org. Chem. 2009, 74, 4393–4395 4393

TABLE 2. Synthesis of r-Aminophosphonates by the Reaction of
Various N-Tosyl Aldimines and Dialkyl Trimethylsilyl Phosphites in
the Presence of Iodinea
The mixture was kept at 0 °C. Dialkyl trimethylsilyl phosphite (1.3
mmol) was subsequently added and the mixture was stirred. The
reaction was monitored by TLC. After completion the reaction was
quenched with hypo solution (10 mL) and the mixture was extracted
with CH2Cl2 (3 × 10 mL). The extract was dried and concentrated
and the residue was subjected to column chromatography (silica
gel, hexane-EtOAc) to obtain pure sulfonamide phosphonate.
1
The spectral (IR, H and 13C NMR, and HRMS) data of the
products are given below.
3a: mp 167-169 °C; IR 3134, 1598, 1456, 1332, 1241, 1165
1
cm-1; H NMR (200 MHz, CDCl3) δ 7.46 (2H, d, J ) 8.0 Hz),
entry
R′
R
time (h)
product
yield (%)b
7.29-7.20 (3H, m), 7.16-7.05 (3H, m), 6.97 (2H, d, J ) 8.0 Hz),
4.84 (1H, dd, J ) 24.0, 10.0 Hz), 3.89 (3H, d, J ) 10.0 Hz), 3.41
(3H, d, J ) 10.0 Hz), 2.24 (3H, s); 13C NMR (50 MHz, CDCl3) δ
142.8, 138.0, 133.4, 129.0, 128.3, 128.0, 127.1, 55.2 (d, J ) 156.2
Hz), 54.4 (d, J ) 6.5 Hz), 54.1 (d, J ) 6.0 Hz), 21.2; HRMS (ESI)
calcd for C16H21NO5PS (MH+) 370.0873, found 370.0874.
1
2
3
4
5
6
7
8
C6H5
Me
Me
Me
Me
Me
Me
Me
Me
Me
Me
Et
1.5
1.5
1.5
1.75
1.5
2.0
2.0
1.75
2.5
2.0
1.5
1.5
1.5
1.5
3a
3b
3c
3d
3e
3f
3g
3h
3i
3j
3k
3l
3m
3n
93
90
92
89
91
87
90
92
86
88
94
92
90
89
3-ClC6H4
4-ClC6H4
3-F,4-ClC6H3
4-NO2C6H4
4-MeOC6H4
4-PhCH2OC6H4
4-MeC6H4
2-furyl
2-thienyl
C6H5
4-ClC6H4
CH3CH2
CH3CH2CH2
3b: mp 145-147 °C; IR 3125, 1458, 1336, 1238, 1162 cm-1
;
1H NMR (200 MHz, CDCl3) δ 7.49 (2H, d, J ) 8.0 Hz), 7.18-7.06
(4H, m), 7.02 (2H, d, J ) 8.0 Hz), 6.90 (1H, dd, J ) 10.0, 4.0
Hz), 4.80 (1H, dd, J ) 24.0, 10.0 Hz), 3.92 (3H, d, J ) 10.0 Hz),
3.49 (3H, d, J ) 10.0 Hz), 2.31 (3H, s); 13C NMR (50 MHz, CDCl3)
δ 143.2, 137.8, 135.1, 134.2, 129.6, 129.2, 128.0, 127.1, 126.5,
55.1 (d, J ) 6.7 Hz), 54.5 (d, J ) 150.2 Hz), 54.2 (d, J ) 6.7 Hz),
21.2; HRMS (ESI) calcd for C16H19ClNO5PSNa (MNa+) 426.0307,
found 426.0325.
9
10
11
12
13
14
Et
Me
Me
a Reaction conditions: N-tosyl aldimine (1.0 mmol), dialkyl trime-
thylsilyl phosphite (1.3 mmol), I2 (20 mol %), DCM (2 mL), 0 °C, N2
atmosphere. b Isolated yield.
3c: mp 203-205 °C; IR 3146, 1598, 1523, 1463, 1306, 1241
cm-1; 1H NMR (200 MHz, CDCl3) δ 7.52 (1H, m), 7.46 (2H, d, J
) 8.0 Hz), 7.24 (2H, d, J ) 8.0 Hz), 7.02 (2H, d, J ) 8.0 Hz),
6.96 (2H, d, J ) 8.0 Hz), 4.81 (1H, dd, J ) 24.0, 10.0 Hz), 3.92
trimethylsilyl phosphites in the presence of iodine. The aromatic
aldehydes contained both electron-donating as well as electron-
withdrawing groups. The aliphatic aldimine derivatives also
afforded the desired phosphonates conveniently. The reaction
was conducted at 0 °C. The conversion was completed within
1.5 to 2.5 h and the sulfonamide phosphonates were formed in
excellent yields (86-94%). Both dimethyl trimethylsilyl phos-
phite and diethyl trimethylsilyl phosphite underwent the conver-
sion smoothly. With the latter reagent the reaction can also be
carried out at room temperature. The structures of the products
(3H, d, J ) 10.0 Hz), 3.48 (3H, d, J ) 10.0 Hz), 2.30 (3H, s); 13
C
NMR (50 MHz, CDCl3) δ 143.4, 138.0, 134.1, 132.2, 129.7, 129.1,
128.6, 127.4, 55.2 (d, J ) 6.8 Hz), 54.5 (d, J ) 150.4 Hz), 54.0
(d, J ) 6.0 Hz), 21.2; HRMS (ESI) calcd C16H20ClNO5PS (MH+)
404.0483, found 404.0492.
3d: mp 164-166 °C; IR 3126, 1600, 1502, 1338, 1238, 1165
cm-1; 1H NMR (200 MHz, CDCl3) δ 7.89 (1H, br dd, J ) 8.0, 2.0
Hz), 7.48 (2H, br d, J ) 8.0 Hz), 7.27 (1H, d, J ) 8.0 Hz), 7.11
(1H, m), 7.01 (2H, d, J ) 8.0 Hz), 6.87 (1H, dd, J ) 10.0, 8.0
Hz), 4.81 (1H, dd, J ) 24.0, 10.0 Hz), 4.01 (3H, d, J ) 10.0 Hz),
3.52 (3H, d, J ) 10.0 Hz), 2.29 (3H, s); 13C NMR (50 MHz, CDCl3)
δ 155.9, 143.2, 138.0, 130.9, 130.2 (d, J ) 8.0 Hz), 129.0, 128.1
(d, J ) 8.0 Hz), 126.9, 121.1 (d, J ) 15.0 Hz), 116.2 (d, J ) 15.0
Hz), 55.3 (d, J ) 6.0 Hz), 54.2 (d, J ) 150.0 Hz), 54.1 (d, J ) 6.0
Hz), 21.2; HRMS (ESI) calcd for C16H19ClFNO5PS (MH+)
422.0389, found 422.0398.
were settled from their spectral (IR, H and 13C NMR, and
HRMS) data.
1
The N-tosyl group of the products can easily be deprotected7
to furnish the corresponding R-amino phosphonates which can
be used to explore their biological properties. It can be
mentioned here that there have been only a few methods
reported1a,3a,4e for the preparation of N-tosyl R-aminophospho-
nates. The catalyst, iodine, is inexpensive, easily available, and
nontoxic. It efficiently conducts the hydrophosphonylation of
N-sulfonylimines by polarizing the -CHdN- bond of the
compounds.
3e: mp 226-228 °C; IR 3133, 1597, 1494, 1337, 1240, 1161
1
cm-1; H NMR (200 MHz, DMSO-d6) δ 9.01 (1H, dd, J ) 10.0,
3.0 Hz), 7.95 (2H, d, J ) 8.0 Hz), 7.51 (2H, d, J ) 8.0 Hz), 7.46
(2H, d, J ) 8.0 Hz), 7.08 (2H, d, J ) 8.0 Hz), 5.10 (1H, dd, J )
24.0, 10.0 Hz), 3.70 (3H, d, J ) 10.0 Hz), 3.49 (3H, d, J ) 10.0
Hz), 2.19 (3H, s); 13C NMR (50 MHz, DMSO-d6) δ 146.6, 142.7,
142.2, 138.0, 129.6, 129.0, 126.8, 122.9, 54.2 (d, J ) 7.2 Hz), 53.3
(d, J ) 6.2 Hz), 52.4 (d, J ) 150.0 Hz), 20.4; HRMS (ESI) calcd
for C16H20N2O7PS (MH+) 415.0723, found 415.0729.
In conclusion, we have developed a facile method for the
synthesis of sulfonamide phosphonates from N-tosyl aldimines
and dialkyl trimethylsilyl phosphites with iodine as a catalyst.
The simple experimental procedure, mild reaction conditions,
application of an easily available catalyst, impressive yields,
and short reaction times are the notable advantages of the
method.
3f: mp 166-168 °C; IR 3128, 1611, 1514, 1334, 1246, 1160
1
cm-1; H NMR (200 MHz, CDCl3) δ 7.49 (2H, d, J ) 8.0 Hz),
7.22-7.11 (3H, m), 6.99 (2H, d, J ) 8.0 Hz), 6.62 (2H, d, J ) 8.0
Hz), 4.70 (1H, dd, J ) 24.0, 10.0 Hz), 3.89 (3H, d, J ) 10.0 Hz),
3.72 (3H, s), 3.41 (3H, d, J ) 10.0 Hz), 2.29 (3H, s); 13C NMR
(50 MHz, CDCl3) δ 159.8, 143.0, 138.1, 129.6, 129.0, 126.9, 125.4,
114.0, 55.1, 54.8 (d, J ) 6.0 Hz), 54.0 (d, J ) 155.5 Hz), 53.9 (d,
J ) 6.0 Hz), 21.2; HRMS (ESI) calcd for C17H22NO6PSNa (MNa+)
422.0798, found 422.0813.
Experimental Section
General Experimental Procedure. Tosylimine (1 mmol) was
taken in CH2Cl2 (2 mL) under N2 and I2 (20 mol %) was added.
3g: mp 214-216 °C; IR 3141, 1609, 1512, 1335, 1241, 1161
1
cm-1; H NMR (200 MHz, CDCl3) δ 7.50 (2H, d, J ) 8.0 Hz),
7.45-7.31 (6H, m), 7.18 (2H, d, J ) 8.0 Hz), 6.99 (2H, d, J ) 8.0
Hz), 6.71 (2H, d, J ) 8.0 Hz), 4.98 (2H, s), 4.81 (1H, dd, J )
24.0, 10.0 Hz), 3.89 (3H, d, J ) 10.0 Hz), 3.41 (3H, d, J ) 10.0
(7) (a) Nandi, P.; Redko, M. Y.; Petersen, K.; Dye, J. L.; Lefenfeld, M.;
Vogt, P. F.; Jackson, J. E. Org. Lett. 2008, 10, 5441. (b) Bajwa, J. S.; Chen,
G.-P.; Prasad, K.; Repic, O.; Blacklock, T. J. Tetrahedron Lett. 2006, 47, 6425.
4394 J. Org. Chem. Vol. 74, No. 11, 2009

Hz), 2.29 (3H, s); 13C NMR (50 MHz, CDCl3) δ 157.7, 142.8,
138.2, 136.9, 129.8, 129.7, 128.9, 128.7, 128.2, 127.8, 127.1, 125.8,
114.6, 70.0, 54.6 (d, J ) 6.0 Hz), 54.2 (d, J ) 150.4 Hz), 54.0 (d,
J ) 6.0 Hz), 21.2; HRMS (ESI) calcd for C23H27NO6PS (MH+)
476.1291, found 476.1300.
(d, J ) 6.2 Hz); HRMS (ESI) calcd for C18H24NO5PSNa (MNa+)
420.1010, found 420.1022.
3l: mp 163-165 °C; IR 3122, 1597, 1492, 1339, 1239, 1161
1
cm-1; H NMR (200 MHz, CDCl3) δ 7.82 (1H, dd, J ) 10.0, 4.0
Hz), 7.40 (2H, d, J ) 8.0 Hz), 7.12 (2H, d, J ) 8.0 Hz), 6.98 (2H,
d, J ) 8.0 Hz), 6.95 (2H, d, J ) 8.0 Hz), 4.72 (1H, dd, J ) 24.0,
10.0 Hz), 4.45-4.28 (2H, m), 3.92 (1H, m), 3.71 (1H, m), 2.29
(3H, s), 1.42 (3H, t, J ) 7.0 Hz), 1.12 (3H, t, J ) 7.0 Hz); 13C
NMR (50 MHz, CDCl3) δ 143.4, 138.0, 133.7, 132.2, 129.9, 129.1,
128.1, 126.6, 64.2 (d, J ) 6.5 Hz), 64.0 (d, J ) 6.5 Hz), 54.9 (d,
J ) 153.7 Hz), 21.2, 16.2 (d, J ) 6.5 Hz), 15.9 (d, J ) 6.5 Hz);
HRMS (ESI) calcd for C18H23ClNO5PSNa (MNa+) 454.0620, found
454.0605.
3h: mp 202-204 °C; IR 3136, 1459, 1337, 1248, 1160 cm-1
;
1H NMR (200 MHz, CDCl3) δ 7.48 (2H, d, J ) 8.0 Hz), 7.09 (2H,
d, J ) 8.0 Hz), 6.99 (2H, d, J ) 8.0 Hz), 6.91 (2H, d, J ) 8.0 Hz),
6.72 (1H, m), 4.78 (1H, dd, J ) 24.0, 10.0 Hz), 3.82 (3H, d, J )
10.0 Hz), 3.40 (3H, d, J ) 10.0 Hz), 2.30 (3H, s), 2.24 (3H, s); 13
C
NMR (50 MHz, CDCl3) δ 143.0, 138.1, 130.2, 129.0, 128.1, 127.2,
54.3 (d, J ) 156.4 Hz), 54.2 (d, J ) 6.2 Hz), 54.0 (d, J ) 6.0 Hz),
21.2, 21.0; HRMS (ESI) calcd for C17H22NO5PSNa (MNa+)
406.0849, found 406.0858.
3m: mp 105-107 °C; IR 3125, 1599, 1468, 1326, 1233, 1162
1
cm-1; H NMR (200 MHz, CDCl3) δ 7.81 (2H, d, J ) 8.0 Hz),
3i: mp 159-161 °C; IR 3126, 1458, 1340, 1249, 1166 cm-1
;
1H NMR (200 MHz, CDCl3) δ 7.58 (2H, d, J ) 8.0 Hz),
7.20-7.711 (3H, m), 6.23 (1H, dd, J ) 10.0, 4.0 Hz), 6.21-6.10
(2H, m), 4.92 (1H, dd, J ) 24.0, 10.0 Hz), 3.85 (3H, d, J ) 10.0
Hz), 3.56 (3H, d, J ) 10.0 Hz), 2.32 (3H, s); 13C NMR (50 MHz,
CDCl3) δ 146.3, 142.8, 142.6, 137.1, 129.0, 127.0, 110.5, 109.9,
54.8 (d, J ) 6.0 Hz), 54.1 (d, J ) 6.0 Hz), 46.8 (d, J ) 156.1 Hz),
21.1; HRMS (ESI) calcd for C14H18NO6PSNa (MNa+) 382.0485,
found 382.0501.
7.29 (2H, d, J ) 8.0 Hz), 6.37 (1H, dd, J ) 10.0, 3.0 Hz), 3.69
(6H, d, J ) 10.0 Hz), 3.61 (1H, m), 2.42 (3H, s), 1.75 (1H, m),
1.59 (1H, m), 0.82 (3H, t, J ) 7.0 Hz); 13C NMR (50 MHz, CDCl3)
δ 143.0, 138.8, 129.5, 127.0, 54.0 (d, J ) 6.2 Hz), 53.2 (d, J ) 6.2
Hz), 51.3 (d, J ) 156.6 Hz), 23.5, 21.3, 10.6 (d, J ) 6.5 Hz);
HRMS (ESI) calcd for C12H20NO5PSNa (MNa+) 344.0697, found
344.0687.
3n: mp 116-118 °C; IR 3110, 1599, 1471, 1330, 1228, 1162
1
cm-1; H NMR (200 MHz, CDCl3) δ 7.79 (2H, d, J ) 8.0 Hz),
3j: mp 150-152 °C; IR 3131, 1465, 1330, 1241, 1161 cm-1
;
1H NMR (200 MHz, CDCl3) δ 7.58 (2H, d, J ) 8.0 Hz), 7.20-6.96
(5H, m), 6.75 (1H, m), 5.10 (1H, dd, J ) 24.0, 10.0 Hz), 3.89 (3H,
d, J ) 10.0 Hz), 3.51 (3H, d, J ) 10.0 Hz), 2.32 (3H, s); 13C NMR
(50 MHz, CDCl3) δ 143.1, 138.4, 135.5, 129.2, 127.7, 126.9, 126.7,
126.1, 54.8 (d, J ) 6.2 Hz), 54.1 (d, J ) 6.0 Hz), 50.2 (d, J )
156.2 Hz), 21.2; HRMS (ESI) calcd for C14H18NO5PS2Na (MNa+)
398.0256, found 398.0267.
7.30 (2H, d, J ) 8.0 Hz), 6.09 (1H, dd, J ) 10.0, 3.0 Hz), 3.72
(1H, m), 3.68 (6H, d, J ) 10.0 Hz), 2.42 (3H, s), 1.67 (1H, m),
1.52 (1H, m), 1.42-1.28 (2H, m), 0.79 (3H, t, J ) 7.0 Hz); 13C
NMR (50 MHz, CDCl3) δ 143.1, 138.6, 129.2, 127.1, 53.9 (d, J )
6.2 Hz), 53.0 (d, J ) 6.2 Hz), 49.9 (d, J ) 155.5 Hz), 32.2, 21.1,
18.2 (d, J ) 6.5 Hz), 13.4; HRMS (ESI) calcd for C13H22NO5PSNa
(MNa+) 358.0854, found 358.0854.
3k: mp 124-126 °C; IR 3109, 1460, 1336, 1239, 1165 cm-1
;
Acknowledgment. The authors thank CSIR and UGC, New
Delhi for financial assistance.
1H NMR (200 MHz, CDCl3) δ 7.99 (1H, m), 7.43 (2H, d, J ) 8.0
Hz), 7.28-7.17 (2H, m), 7.12-6.93 (3H, m), 6.85 (2H, d, J ) 8.0
Hz), 4.79 (1H, dd, J ) 24.0, 10.0 Hz), 4.42-4.28 (2H, m), 3.88
(1H, m), 3.60 (1H, m), 2.21 (3H, s), 1.42 (3H, t, J ) 7.0 Hz), 1.02
(3H, t, J ) 7.0 Hz); 13C NMR (50 MHz, CDCl3) δ 143.2, 138.4,
134.5, 129.1, 128.7, 128.0, 126.8, 64.6 (d, J ) 6.0 Hz), 64.4 (d, J
) 6.2 Hz), 54.9 (d, J ) 151.2 Hz), 20.4, 15.3 (d, J ) 6.0 Hz), 15.1
Supporting Information Available: Spectra (1H and 13C
NMR and HRMS) of the products 3a-n. This material is
available free of charge via the Internet at http://pubs.acs.org.
JO9003162
J. Org. Chem. Vol. 74, No. 11, 2009 4395