Compound 4a : mp 146-148 °C (lit.11 mp 151-152 °C); 1H
NMR (200 MHz, CDCl3) δ 7.62-7.54 (m, 15H), 4.38 (q, J ) 7.1
Hz, 2H), 1.41 (t, J ) 7.1 Hz, 3H); IR νmax 1665, 1445, 1260, 1105,
In conclusion, the preparation and the structure of the
R-hypervalent iodine functionalized phosphonium and
arsonium ylides 2 are reported. These ylides 2 can be
used as umpolung ylides to react with nucleophiles 3,
giving R-heteroatom substituted ylides 4 in good yields.
The present new type of tandem sequence of nucleophilic
substitution-Wittig reaction provides an efficient method
for the synthesis of (Z)-R-halo-R,â-unsaturated enoates
or enones 6 stereoselectively in moderate to excellent
yields. The discovery on the umpolung ylides 2 would
enrich the contents of ylide chemistry.
740, 690 cm-1
.
Compound 4b: mp 155-156 °C (lit.11 mp 157-158 °C); 1H
NMR (200 MHz, CDCl3) δ 7.62-7.53 (m, 15H), 4.37 (q, J ) 7.1
Hz, 2H), 1.39 (t, J ) 7.1 Hz, 3H); IR νmax 1651, 1435, 133, 1184,
744, 693 cm-1
.
Compound 4c: mp 197-199 °C (lit.13 mp 199 °C); 1H NMR
(200 MHz, CDCl3) δ 8.11-7.01 (m, 20H), 4.32 (q, J ) 7.1 Hz,
2H), 1.36 (t, J ) 7.1 Hz, 3H); IR νmax 1657, 1450, 1320, 1009,
742, 691 cm-1
.
Compound 4d : mp 184-186 °C (lit.14 mp 184-186 °C); 1H
NMR (200 MHz, CDCl3) δ 7.62-7.54 (m, 20H), 4.37 (q, J ) 7.1
Hz, 2H), 1.38 (t, J ) 7.1 Hz, 3H); IR νmax 1653, 1485, 1310, 1060,
Exp er im en ta l Section
743, 692 cm-1
.
All reactions were carried out in Schlenk tubes under nitrogen
atmosphere. Mass spectra were obtained by EI method. IR
spectra were taken the neat forus (liquid samples) or KBr disks
(solid samples). Melting points were uncorrected.
1
Compound 4e: mp 185-186 °C; H NMR (200 MHz, CDCl3)
δ 7.37-7.07 (m, 20H), 3.63 (s, 3H); IR νmax 1600, 1485, 1300,
760, 720 cm-1; MS m/z (rel intensity) 486 (M+, 24), 306 (14),
227 (36), 152 (100), 109 (8), 77 (7). Anal. Calcd for C27H23
-
Gen er a l P r oced u r e for th e Syn th esis of r-Hyp er va len t
Iodin e Fu n ction alized P h osph on iu m an d Ar son iu m Ylides
2a -d . A solution of PhI(OAc)2 (5 mmol) and HBF4 (5 mmol) in
MeOH (5 mL) was added dropwise to the ice bath-cooled solution
of ylide 1 (5 mmol) in MeOH (5 mL) for 20 min with stirring.
During the addition, a lot of precipitate was formed. Upon
complete addition, the reaction mixture was stirred at 0 °C for
additional 1.5 h. After filtration, the precipitate was washed with
Et2O (5 mL × 3), recrystallized from CH2Cl2-MeOH, and dried
under vacuum to give 2a -d .
AsO2S: C, 66.67; H, 4.77. Found: C, 66.49; H, 4.89.
1
Compound 4f: mp 163-164 °C; H NMR (200 MHz, CDCl3)
δ 7.81-7.66 (m, 19H), 3.94 (q, J ) 7 Hz, 2H), 2.11 (s, 3H), 0.98
(t, J ) 7 Hz, 3H); IR νmax 1605, 1500, 1290, 800, 745, 690 cm-1
;
MS m/z (rel intensity) 514 (M+, 11), 416 (32), 306 (74), 229 (39),
152 (100), 91 (11), 77 (15). Anal. Calcd for C29H27AsO2S: C,
67.70; H, 5.29. Found: C, 67.40; H, 5.40.
Compound 4g: mp 202-203 °C (lit.15 mp 203-205 °C); 1H
NMR (200 MHz, CDCl3) δ 7.70-7.09 (m, 20H), 3.41 (s, 3H); IR
νmax 1600, 1445, 1300, 750, 690 cm-1
.
Compound 2a : yield 88%; mp 185-186 °C (lit.9 mp 185-187
Gen er a l P r oced u r e for th e Ster eoseletive Syn th esis of
(Z)-r-Ha lo-r,â-u n sa tu r a ted Ester s 6 by th e Ta n d em Rea c-
tion of Um p olu n g Ylid es 2. A mixture of R-hypervalent iodine
functionalized phosphonium or arsonium ylides 2 (2 mmol),
tetrakisalkylammonium halide 3 (2 mmol), and aldehyde 5 (2
mmol) in CH2Cl2 (20 mL) was stirred at room temperature for
8-48 h. After the reaction was complete, the organic phase was
washed with water (10 mL × 2) and dried over magnesium
sulfate. After evaporation of the solvent, the crude product was
purified by preparative TLC (silica gel, hexanes-ethyl acetate
as eluent) to give R-halo-R,â-unsaturated enoate or enone 6.
Eth yl 2-ch lor o-3-(4-ch lor op h en yl)-2-p r op en oa te (6a ): oil
1
°C); H NMR (200 MHz, CDCl3) δ 7.62-7.54 (m, 20H), 4.32 (q,
J ) 7.1 Hz, 2H), 1.36 (t, J ) 7.1 Hz, 3H); IR νmax 1601, 1436,
1284, 1065, 740, 694 cm-1
.
Compound 2b: yield 81%; mp 174-178 °C dec; 1H NMR (200
MHz, CDCl3) δ 7.62-7.54 (m, 20H), 3.67 (s, 3H); IR νmax 1560,
1484, 1363, 1055, 740, 693 cm-1. Anal. Calcd for C27H23BF4-
IOP: C, 53.32; H, 3.81; I, 20.87. Found: C, 53.07; H, 3.83; I,
20.75.
Compound 2c: yield 75%; mp 109-111 °C dec; 1H NMR (200
MHz, CDCl3) δ 7.62-7.54 (m, 20H), 3.67 (s, 3H); IR νmax 1600,
1445, 1310, 1060, 740, 690 cm-1. Anal. Calcd for C27H23AsBF4-
IO2: C, 48.54; H, 3.47; I, 18.99. Found: C, 48.45; H, 3.58; I, 18.79.
Crystallographic data for the structure (2c) reported has been
deposited with Cambridge Crystallographic Data Centre as
supplementary publication no. CCDC 189966.
1
(lit.16 oil); H NMR (400 MHz, CDCl3) δ 7.85 (s, 1H), 7.77 (d, J
) 8.5 Hz, 2H), 7.39 (d, J ) 8.5 Hz, 2H), 4.36 (q, J ) 7.1 Hz, 2H),
1.39 (t, J ) 7.1 Hz, 3H); IR νmax 2983, 1728, 1618, 1491, 1262,
1198, 823 cm-1; MS m/z (rel intensity) 244 (M+, 31), 185 (36),
138 (37), 136 (100), 135 (31), 75 (36).
Compound 2d : yield 82%; mp 109-110 °C dec; 1H NMR (200
MHz, CDCl3) δ 7.70-7.40 (m, 20H), 4.06 (q, J ) 7 Hz, 2H), 1.03
Eth yl 2-ch lor o-3-p h en yl-2-p r op en oa te (6b): oil (lit.17 95/
0.2 mm); 1H NMR (400 MHz, CDCl3) δ 7.9 (s, 1H), 7.85-7.83
(m, 2H), 7.43-7.41 (m, 3H), 4.36 (q, J ) 7.1 Hz, 2H), 1.39 (t,
3H, J ) 7.1 Hz); IR νmax 2982, 1723, 1611, 1447, 1258, 1182,
765, 691 cm-1; MS m/z (rel intensity) 212 (M+ + 2, 33), 210 (M+,
100), 175 (37), 147 (55), 102 (86).
Eth yl 2-ch lor o-3-(4-m eth ylp h en yl)-2-p r op en oa te (6c): oil
(lit.18 bp 150-152 °C/3 mm); 1H NMR (400 MHz, CDCl3) δ 7.74
(d, J ) 8.0 Hz, 2H), 7.56 (s, 1H), 7.24 (d, J ) 8.0 Hz, 2H), 4.36
(q, J ) 7.1 Hz, 2H), 1.39 (t, J ) 7.1 Hz, 3H); IR νmax 2982, 1726,
1608, 1511, 1263, 1183, 1044, 813 cm-1; MS m/z (rel intensity)
226 (M+ + 2, 37), 225 (M+ + 1, 45), 224 (M+, 100), 179 (23), 115
(68), 116 (43).
(t, J ) 7 Hz, 3H); IR νmax 1600, 1445, 1290, 1055, 740, 685 cm-1
.
Anal. Calcd for C28H25AsBF4IO2: C, 49.30; H, 3.69; I, 18.60.
Found: C, 49.21; H, 3.59; I, 18.70.
Gen er a l P r oced u r e for th e Syn th esis of r-Heter oa tom -
Su bstitu ted P h osp h on iu m a n d Ar son iu m Ylid es 4a -g by
th e Nu cleoph ilic Su bstitu tion of Um polu n g Ylide 2. Meth od
A. A solution of a nucleophile (for tetramethylamomnium
chloride or tetrabutylammonium bromide, CH2Cl2 was used as
the solvent; for sodium selenolate, MeOH was used as the
solvent) was added dropwise to the solution of R-hypervalent
iodine functionalized phosphonium or arsonium ylides 2 (2
mmol) in CH2Cl2 (6 mL) within 30 min with stirring. The
reaction mixture was then stirred overnight. The solvent was
evaporated and the residue was extracted with C6H6 (15 mL ×
3). After filtration the filtrate was evaporated to obtain a solid.
Recrystallization of this solid from acetone-hexane gave the pure
R-heteroatom substituted phosphonium and arsonium ylides
4a -g.
Eth yl 2-br om o-3-(4-n itr op h en yl)-2-p r op en oa te (6d ): mp
154-156 °C (lit.11b mp 154-156 °C); 1H NMR (400 MHz, CDCl3)
δ 8.29 (m, 3H), 7.94 (d, J ) 8.6 Hz, 2H), 4.38 (q, J ) 7.1 Hz,
2H), 1.40 (t, J ) 7.1 Hz, 3H); IR νmax 3050, 1710, 1610, 1511,
Meth od B. A solution of thiophenol (2 mmol) in CH3CN (3
mL) was added dropwise to an ice-bath cooled mixture of
R-hypervalent iodine functionalized phosphonium or arsonium
ylides 2 (2 mmol) and K2CO3 (2 mmol) in CH3CN (6 mL) within
30 min with stirring. The reaction mixture was then stirred
overnight. R-Heteroatom-substituted phosphonium and arso-
nium ylides 4c and 4e,f were obtained after the workup similar
to that in method A.
(13) Saikuchi, H.; Nakamura, S. Yakugaku Zasshi 1968, 88, 715.
(14) Petragnani, N.; Campos, M. M. Chem. Ind. (London) 1964, 1461.
(15) Huang, Z. Z.; Huang, X.; Huang, Y. Z. J . Organmet. Chem. 1995,
C23-C26, 490.
(16) Son, J . S.; J ung, K. S.; Kim, H. R.; Kim, J . N. Synth. Commun.
1998, 28, 1847.
(17) Tay, M. K.; About-J audet, E,; Collignon, N. Synth. Commun.
1988, 18, 1349.
(18) Marmlnov, V. F.; Timov, M. I. Zh. Obsh. Khim. 1964, 34, 2125.
J . Org. Chem, Vol. 67, No. 23, 2002 8263