Reactivity in the formation of lactones from aromatic carboxylic acids with organohypervalent iodine compounds in the Suarez system

Article abstract of DOI:10.1039/a900791a

The reactivity of various iodanes, such as (diacetoxyiodo)arenes, the Dess-Martin reagent, and (arylsulfonyloxy)benziodoxolones, with (o-alkyl)- and (o-phenyl)arenecarboxylic acids in the presence of iodine (Suarez system) was studied to give the corresponding lactones via oxygen-centered radicals. (Diacetoxyiodo)arenes gave the lactones in good yields, while 1-(arylsulfonyloxy)benziodoxolones gave lactones together with the iodinated lactones. The Dess-Martin reagent also showed the same reactivity as (diacetoxyiodo)arenes to give the lactones. Among them, (diacetoxyiodo)toluene showed the best reactivity for the conversion of these carboxylic acids to the corresponding lactones.

Full text of DOI:10.1039/a900791a

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Reactivity in the formation of lactones from aromatic carboxylic
acids with organohypervalent iodine compounds in the Suárez
system
Takahito Muraki,a Hideo Togo*a,b and Masataka Yokoyamaa,b
a Graduate School of Science and Technology, Chiba University, Inage-ku,
Chiba 263-8522 Japan
b Department of Chemistry, Faculty of Science, Chiba University, Inage-ku,
Chiba 263-8522 Japan
Received (in Cambridge) 29th January 1999, Accepted 23rd April 1999
The reactivity of various iodanes, such as (diacetoxyiodo)arenes, the Dess–Martin reagent, and (arylsulfonyloxy)-
benziodoxolones, with (o-alkyl)- and (o-phenyl)arenecarboxylic acids in the presence of iodine (Suárez system) was
studied to give the corresponding lactones via oxygen-centered radicals. (Diacetoxyiodo)arenes gave the lactones
in good yields, while 1-(arylsulfonyloxy)benziodoxolones gave lactones together with the iodinated lactones. The
Dess–Martin reagent also showed the same reactivity as (diacetoxyiodo)arenes to give the lactones. Among them,
(diacetoxyiodo)toluene showed the best reactivity for the conversion of these carboxylic acids to the corresponding
lactones.
reagent.1 Furthermore, a typical organopentavalent iodine
Introduction
compound, the Dess–Martin periodane (DMP, 1G), is a very
useful oxidation reagent of alcohols.3 In radical reactions,1f,i
iodane 1A has been often used as the precursor of alkyl rad-
icals4 and oxygen-centered radicals (i.e., the Suárez system).5,6
Thus, in the Suárez system, a mixture of a trivalent iodine
compound, iodine, and alcohol or carboxylic acid is exposed
to light to generate the corresponding alkoxyl5 or carbonyloxyl
radicals,5j and used for organic synthesis. In this system
(diacetoxyiodo)benzene and iodosylbenzene (1H) have been
commonly used.7 However, the reactivity with various organo-
hypervalent iodine compounds has been never studied. Thus,
we planned to compare the reactivities with various organo-
hypervalent iodine compounds, as shown in Fig. 1, in the
formation of lactones from arenecarboxylic acids. Since there
are many kinds of natural products and bioactive compounds
containing γ- and δ-lactones, direct synthetic methods for these
skeletons are very important.8
Recently, the study and synthetic use of organohypervalent
iodine compounds have been widely carried out.1 For example,
in ionic reactions, (diacetoxyiodo)benzene (1A) and [bis(tri-
fluoroacetoxy)iodo]benzene (1E) have been used extensively as
oxidants,1,2 and the trivalent iodine compound having a sulfonyl-
oxy group, [hydroxy(tosyloxy)iodo]benzene (Koser’s reagent,
1I), has been used as a powerful carbon–carbon bond forming
O
OAc
O
I
R
R
X
I
O
O
O
O
1A : R = CH3; X = H
1F
1B : R = CH3; X = OCH3
1C : R = CH3; X = CH3
1D : R = CH3; X = Cl
1E : R = CF3; X = H
Results and discussion
We have already reported on the lactonization of ortho-
substituted benzoic acids with [bis(trifluoroacetoxy)iodo]-
benzene (1E) and iodine.5j There, we used four types of
arenecarboxylic acids, 2-ethylbenzoic acid (2a), 2,5-diisopropyl-
benzoic acid (2b), 2-benzylbenzoic acid (2c), and 2-phenyl-
benzoic acid (2d), as typical 2-substituted benzoic acids. Here,
the lactonization of acids 2a–2d with iodanes 1A–1H is shown
in Table 1, and a plausible reaction mechanism is shown in
Scheme 1.
In para-substituted (diacetoxyiodo)benzenes 1A–1D, a large
difference in the formation of lactones was not observed, i.e.,
para-substituents do not affect significantly these lactoniz-
ations. However with [bis(trifluoroacetoxy)iodo]benzene (1E),
the yields of lactones 3a and 3b were decreased. The cyclic
trivalent iodine compound 1F gave the corresponding lactones
in poor yields. Interestingly, the Dess–Martin reagent 1G con-
verted benzoic acid derivatives to the corresponding lactones in
moderate to good yields. In iodosylbenzene (1H), lactones were
formed in poor yields, because of the poor solubility of iodane
1H. When the reactivities of (diacetoxyiodo)benzene (1A),
OAc
OAc
OAc
I
(PhIO)n
O
O
1G
1H
O
S
O
O
X
O
S
CH3
O
O
I
I
O
OH
O
1J : X = CH3
1K : X = Cl
1I
1L : X = NO2
Fig. 1 Various organohypervalent iodines 1.
J. Chem. Soc., Perkin Trans. 1, 1999, 1713–1716
1713

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Table 1 Cyclization of acids 2a–2d with iodanes 1A–1H
Table 2 Cyclization of 2-substituted benzoic acids with trivalent
iodine compounds having sulfonyloxy groups
1
(1.1 eq.)
R1
1
I2 (1.1 eq.)
R
I2 (1.1 eq.)
Lactone
OH
Lactone
R2
ClCH2CH2Cl, hν
OH
ClCH2CH2Cl, hν
3
O
2
O
2
3
Yields of lactones (%)a
3ab
3bc
3cc
3dd
Entry
1
2
Lactonesa
Yields (%)
Iodanes
1
2
3
4
5
6
7
8
9
1I
2c
2c
2c
2c
2c
2d
2d
2d
2d
2d
3c/3c-ip
3c/3c-ip
3c/3c-ip
3c/3c-ip
3c/3c-ip/3c-io
3d
3d/3d-i
3d/3d-i
3d/3d-i
3d-i
15/15b
13/38b
3/39b
2/30b
2/19/11c
27d
1A
1B
1C
1D
1E
1F
53
49
56
56
40
6
83
82
91
91
36
10
61
37
72
61
68
68
70
13
58
27
89
74
99
86
90
12
83
41
1J
1K
1L
1K
1I
1J
1K
1L
1K
36/5d
39/10d
41/6d
49e
1G
1H
44
22
a Structure of lactones:
10
a Structure of lactones:
Me
Me
Me
I
O
O
O
O
3a
3b
I
I
O
O
O
O
Ph
O
O
O
3c-ip
3c-io
3d-i
b Ratio of 1:2 is 1.1:1.0 and irradiation with a high-pressure Hg lamp
for 5 h at rt. c Ratio of 1:2 is 2.2:1.0 and irradiation with a high-
pressure Hg lamp for 5 h at rt. d Ratio of 1:2 is 1.1:1.0 and irradiation
with a tungsten lamp for 2 h at 60–70 ЊC. e Ratio of 1:2 is 2.2:1.0 and
irradiation with a tungsten lamp for 2 h at 60–70 ЊC.
O
O
O
3c
3d
b Irradiation with a high-pressure Hg lamp at rt for 5 h in ClCH2CH2Cl
(5 ml). c Irradiation with a high-pressure Hg lamp at rt for 5 h in
ClCH2CH2Cl (10 ml). d Irradiation with a tungsten lamp at 60–70 ЊC
for 2 h in ClCH2CH2Cl (10 ml).
converted to the corresponding lactones, in moderate yields.
Furthermore, iodinated lactones 3c-ip, 3c-io, and 3d-i were
also obtained, and these compounds were not obtained using
iodanes bearing acyloxy groups (1A–1G). Probably, this is due
to the powerful iodination ability of aromatic rings with
iodanes 1I–1L as compared with iodanes 1A–1E, in the pres-
ence of iodine.9 Thus, iodinated lactones 3c-ip, 3c-io, and 3d-i
were produced through the formation of lactone skeletons as
shown in Scheme 1 and iodination of the aromatic rings by the
arenesulfonyl hypoiodite species via the ionic pathway. Actually,
under the dark conditions, iodane 1J iodinated benzo[c]-
chromen-6-one (3d) to give iodinated lactone 3d-i in 24% yield
in the presence of iodine at room temperature. The large differ-
ence in reactivity between acyloxy and sulfonyloxy groups in
iodanes 1 probably comes from the facts that sulfonyloxy
groups have better leaving ability than acyloxy groups, and that
the sulfonyl hypoiodite species formed in situ are more powerful
iodination reagents for aromatic rings than acyl hypoiodite
species. Here, since lactones 3c and 3c-ip could not be separated
by preparative TLC (silica gel), the yields were determined
R
R
I (III) or I (V) / I2
H
H
O
OH
I
O
O
R
R
hν
H
O
OH
O
R
O
R
I
I2
O
OH
– HI
O
O
1
by the integral ratio obtained from H NMR. However, yields
Scheme 1 Plausible reaction mechanism.
were lower than those with iodanes 1A–1E and 1G, and so
improvement of reaction conditions was attempted. In benz-
iodoxolones, the amount of iodane 1K was increased to 2.2
equiv. (Entries 5 and 10, Table 2). Thus, in entry 10, lactone 3d-i
was obtained in 49% yield as the sole product and benzo[c]-
chromen-6-one (3d) completely disappeared. This result again
confirms that benziodoxolones 1J–1L are more powerful iodin-
ation reagents than 1A–1F.9 The lactonization of acids 2a and
2b with 1I–1L did not occur because of decomposition of the
iodanes in the presence of iodine. Thus, for the lactonization of
arenecarboxylic acids, iodane 1A–1E and 1G should be used.
The reactivities are shown in Fig. 2 based on Table 1.
1-(acetoxy)benziodoxolone (1F), and the Dess–Martin reagent
(1G) are compared, the yields of lactones 3a–3d decreased in
the order of 1A > 1G > 1F. From the structural point of view,
the benziodoxole skeleton retarded reactions such as the acyl-
oxy exchange reaction and the formation of hypoiodite species
because of their rigid structure, and so iodane 1F gave the lac-
tones in poor yields. DMP 1G overcame this disadvantage
owing to its powerful oxidation ability derived from the penta-
valent iodine atom. Then trivalent iodine compounds having
sulfonyloxy groups 1I–1L were used in this reaction system to
give the corresponding lactones (Table 2).
2-Benzylbenzoic acid (2c) and 2-phenylbenzoic acid (2d) were
In conclusion, (diacetoxyiodo)arenes gave the lactones in
1714
J. Chem. Soc., Perkin Trans. 1, 1999, 1713–1716

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δ = 120.37 (q), 126.25 (t), 127.42 (t), 127.64 (t), 130.31 (t),
131.04 (t), 131.48 (q), 132.93 (q), 134.42 (t), 147.16 (q), 167.68
(q); Found: C, 35.72; H, 1.92%. Calcd. for C13H6ClIO5S: C,
35.60; H, 1.84%.
1-(p-Nitrophenylsulfonyloxy)-1ë3,2-benziodoxol-3(1H)-one
(1L). Mp 180–181 ЊC (decomp.); IR (KBr) 3080, 1610, 1510,
1
1240, 1120, and 740 cmϪ1; H NMR (400 MHz, DMSO-d6)
δ = 7.68 (1H, t, J = 7.1 Hz), 7.81–7.85 (3H, m), 7.94 (1H, td,
J = 7.5, 1.5 Hz), 7.99 (1H, dd, J = 7.5, 1.3 Hz), 8.18 (1H, d,
J = 8.8 Hz); 13C NMR (100 MHz, DMSO-d6) δ = 120.41 (q),
123.33 (t), 126.28 (t), 126.90 (t), 130.36 (t), 131.03 (t), 131.48
(q), 134.47 (t), 147.27 (q), 154.22 (q), 167.74 (q); Found: C,
34.55; H, 2.01; N, 2.97%. Calcd. for C13H8INO7S: C, 34.76; H,
1.80; N, 3.12%.
Fig. 2 Reactivity map of iodanes 1A–1H in the Suárez system.
3-Methylphthalide (3a). Oil; IR (neat) 2940, 1740, 1590, 1450,
1210, 760, and 740 cmϪ1; 1H NMR (500 MHz, CDCl3) δ = 1.64
(3H, d, J = 6.7 Hz, CH3), 5.57 (1H, q, J = 6.7 Hz, 3-H), 7.45
(1H, dd, J = 7.3, 0.9 Hz, 4-H), 7.53 (1H, t, J = 7.7 Hz, 6-H), 7.68
high yields; in particular, (diacetoxyiodo)toluene showed the
best reactivity for the cyclization of aromatic carboxylic acids.
1-(Acetoxy)benziodoxolone (1F) gave the lactones in poor
yields because of their rigid structure. The Dess–Martin reagent
also reacted in this system. Only trivalent iodine compounds
having sulfonyloxy groups gave the iodinated lactones, since
these iodanes have powerful iodination ability.
(1H, td, J = 7.3, 0.9 Hz, 5-H), 7.89 (1H, d, J = 7.7 Hz, 7-H); 13
C
NMR (125 MHz, CDCl3) δ = 20.38 (p, CH3), 77.85 (t, 3-C),
121.57 (t, 4-C), 125.72 (t, 7-C), 129.10 (t, 6-C), 134.12 (t, 5-C),
151.23 (q, Ar), 170.63 (q, CO); Found: C, 73.13; H, 5.27%.
Calcd. for C9H8O2: C, 72.96; H, 5.44%; HRMS (FAB) Found:
(M ϩ H)ϩ = 149.0627. Calcd. for C9H9O2: M ϩ H = 149.0603.
Experimental
General
3,3-Dimethyl-6-isopropylphthalide (3b). Oil; IR (neat) 2930,
1750, 1580, 1490, 1190, 800, and 740 cmϪ1 1H NMR (400
;
1H NMR spectra were recorded on 400 MHz and 500 MHz
spectrometers and 13C NMR spectra were recorded on 100
MHz and 125 MHz spectrometers; p, q and t indicate primary,
quaternary and tertiary centres, respectively. Chemical shifts
are reported as ppm downfield from tetramethylsilane (TMS) in
δ units. J-Values are given in Hz. The matrix of high resolution
mass spectra (FAB) used 3-nitrobenzyl alcohol. Melting points
were determined on an electrothermal apparatus in open
capillary tubes and are uncorrected. Wakogel C-200 was used
for column chromatography, Kieselgel 60 F254 (Merck) was
used for TLC, and Wakogel B-5F was used for pTLC.
MHz, CDCl3) δ = 1.29 (6H, d, J = 7.0 Hz, isopropyl-CH3), 1.65
(6H, s, CH3), 3.02 (1H, septet, J = 7.0 Hz, isopropyl-CH), 7.31
(1H, d, J = 8.1 Hz, 4-H), 7.53 (1H, dd, J = 8.1, 1.7 Hz, 5-H),
7.72 (1H, d, J = 1.7 Hz, 7-H); 13C NMR (100 MHz, CDCl3)
δ = 23.92 (p, isopropyl-CH3), 27.40 (p, CH3), 33.98 (t, iso-
propyl-CH), 85.32 (q, 3-C), 120.47 (t, 4-C), 123.07 (t, 7-C),
125.48 (q, Ar), 133.09 (t, 5-C), 150.25 (q, Ar), 152.75 (q, Ar),
170.17 (q, CO); Found: C, 76.20; H, 7.77%. Calcd. for C13H16O2:
C, 76.44; H, 7.90%; HRMS (FAB) Found: (M ϩ H)ϩ =
205.1229. Calcd. for C13H17O2: M ϩ H = 205.1229.
3-Phenylphthalide (3c). Mp 113.0–114.0 ЊC; IR (KBr) 3000,
Materials
1740, 1580, 1455, 1280, 970, and 740 cmϪ1 1H NMR (500
;
The iodanes 1A, 1E, 1H, 1I and aromatic carboxylic acids 2c
and 2d are commercially available. The other (diacetoxy-
iodo)arenes were prepared by the oxidation of the corre-
sponding iodoarenes with NaBO4ؒ4H2O in acetic acid.10
Benziodoxolone derivatives 1F,11 1G,3 and 1J12 were prepared
based on the literature method. Iodanes 1K and 1L were
prepared with the same method of iodane 1J.
MHz, CDCl3) δ = 6.41 (1H, s, 3-H), 7.26–7.28 (2H, m, phenyl),
7.33 (1H, d, J = 7.6 Hz, 4-H), 7.36–7.37 (3H, m, phenyl), 7.56
(1H, t, J = 7.3 Hz, 6-H), 7.65 (1H, t, J = 7.3 Hz, 5-H), 7.97 (1H,
d, J = 7.7 Hz, 7-H); 13C NMR (125 MHz, CDCl3) δ = 87.73
(t, 3-C), 122.90 (t, 4-C), 125.64 (t, 7-C), 126.98 (t, Ph), 128.99
(t, Ph), 129.31 (t, 6-C), 129.38 (q, Ar), 134.34 (t, 5-C), 136.46
(q, Ar), 149.71 (q, Ar), 170.52 (q, CO); Found: C, 79.81; H,
4.92%. Calcd. for C13H8O2: C, 79.98; H, 4.79%; HRMS (EI)
Found: Mϩ = 210.0678. Calcd. for C14H10O2: M = 210.0681.
Typical procedures
To a solution of iodine (1.1 mmol) were added iodane (1.1
mmol) and the appropriate aromatic carboxylic acid (1.0
mmol). The solution was irradiated with a high-pressure mer-
cury lamp (400 W) for 5 h at rt (or irradiated with a tungsten
lamp (500 W) for 2 h at 60–70 ЊC). Then the reaction mixture
was poured into sat. aq. NaHCO3 solution and extracted with
chloroform three times. The organic layer was poured into sat.
aq. Na2SO3 solution and extracted with chloroform. Finally,
the organic layer was dried over Na2SO4. After removal of the
solvent under reduced pressure, the residual oil was purified by
preparative TLC on silica gel using hexane–EtOAc (4:1) (or
toluene–EtOAc = 30:1) as an eluent.
3-(4Ј-Iodophenyl)phthalide (3c-ip). IR (KBr) 3060, 1760,
1
1600, 1480, 1000, and 800 cmϪ1; H NMR (500 MHz, CDCl3)
δ = 6.34 (1H, s, 3-H), 7.03 (2H, d, J = 8.6 Hz, 2Ј, 6Ј-H), 7.32
(1H, d, J = 7.6 Hz, 4-H), 7.57 (1H, t, J = 7.3 Hz, 6-H), 7.66 (1H,
td, J = 7.6, 1.1 Hz, 5-H), 7.72 (2H, d, J = 8.2 Hz, 3Ј, 5Ј-H), 7.96
(1H, d, J = 7.7 Hz, 7-H); 13C NMR (125 MHz, CDCl3)
δ = 81.94 (t, 3-C), 95.19 (q, 4Ј-C), 122.75 (t, 4-C), 125.80 (t,
7-C), 128.71 (t, 2Ј 6Ј-C), 129.59 (t, 6-C), 134.47 (t, 5-C), 136.20
(q, Ar), 138.16 (t, 3Ј, 5Ј-C), 149.15 (q, Ar), 170.20 (q, CO);
HRMS (FAB) Found: (M ϩ H)ϩ = 336.9721. Calcd. for C14H10-
O2I: M ϩ H = 336.9726.
1-(p-Chlorophenylsulfonyloxy)-1ë3,2-benziodoxol-3(1H)-one
(1K). Mp 172–173 ЊC (decomp.); IR (KBr) 3080, 1610, 1230,
3-(2Ј-Iodophenyl)phthalide (3c-io). Mp 121.0–122.0 ЊC; IR
(KBr) 2920, 1770, 1610, 1480, 1280, 1060, 760, and 740 cmϪ1
;
1180, and 760 cmϪ1; H NMR (400 MHz, DMSO-d6) δ = 7.36
1H NMR (500 MHz, CDCl3) δ = 6.83 (1H, s, 3-H), 6.95 (1H,
dd, J = 8.0, 1.5 Hz, 6Ј-H), 7.06 (1H, td, J = 7.9, 1.7 Hz, 4Ј-H),
7.28 (1H, td, J = 7.3, 1.2 Hz, 5Ј-H), 7.55–7.59 (2H, m, 4, 6-H),
7.65 (1H, td, J = 7.3, 0.9 Hz, 5-H), 7.93 (1H, dd, J = 8.0, 1.3 Hz,
1
(2H, d, J = 8.5 Hz), 7.59 (2H, d, J = 8.2), 7.68 (1H, td, J = 7.3,
1.0 Hz), 7.83 (1H, d, J = 7.5 Hz), 7.94 (1H, td, J = 7.3, 1.7 Hz),
8.00 (1H, dd, J = 7.6, 1.5 Hz); 13C NMR (100 MHz, DMSO-d6)
J. Chem. Soc., Perkin Trans. 1, 1999, 1713–1716
1715

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3Ј-H), 7.97 (1H, d, J = 7.3 Hz, 7-H); 13C NMR (125 MHz,
CDCl3) δ = 85.60 (t, 3-C), 98.02 (q, 2Ј-C), 123.06 (t, 4-C),
125.38 (q, Ar), 125.84 (t, 7-C), 127.62 (t, 6Ј-C), 128.91 (t, 5Ј-C),
129.60 (t, 6-C), 130.83 (t, 4Ј-C), 134.49 (t, 5-C), 139.23 (q, Ar),
139.98 (t, 3Ј-C), 149.42 (q, Ar), 170.45 (q, CO); Found: C,
49.79; H, 2.51%. Calcd. for C14H9O2I: C, 50.03; H, 2.70%;
HRMS (FAB) Found: (M ϩ H)ϩ = 336.9715. Calcd. for C14H10-
O2I: M ϩ H = 336.9726.
(j) T. Kitamura and Y. Fujiwara, Org. Prep. Proced. Int., 1997, 29,
409; (k) A. Varvoglis and S. Spyroudis, Synlett, 1998, 221; (l) R. M.
Moriarty and O. Prakash, Adv. Heterocycl. Chem., 1998, 69, 1.
2 N. A. Braun, M. A. Ciufolini, K. Peters and E.-M. Peters,
Tetrahedron Lett., 1998, 39, 4667.
3 (a) D. B. Dess and J. C. Martin, J. Org. Chem., 1983, 48, 4156;
(b) D. B. Dess and J. C. Martin, J. Am. Chem. Soc., 1991, 113, 7277;
(c) R. E. Ireland and L. J. Liu, J. Org. Chem., 1993, 58, 2899; (d)
S. D. Meyer and S. L. Schreiber, J. Org. Chem., 1994, 59, 7549; (e)
S. De Munari, M. Frigerio and M. Santagostino, J. Org. Chem.,
1996, 61, 9272.
4 (a) H. Togo, M. Aoki and M. Yokoyama, Tetrahedron Lett., 1991,
32, 6559; (b) H. Togo, M. Aoki and M. Yokoyama, Chem. Lett.,
1991, 1691; (c) H. Togo, M. Aoki and M. Yokoyama, Tetrahedron,
1993, 49, 8241; (d) H. Togo, M. Aoki, T. Kuramochi and M.
Yokoyama, J. Chem. Soc., Perkin Trans. 1, 1993, 2417; (e) H. Togo,
R. Taguchi, K. Yamaguchi and M. Yokoyama, J. Chem. Soc., Perkin
Trans. 1, 1995, 2135; ( f ) H. Togo, T. Muraki and M. Yokoyama,
Synthesis, 1995, 155.
5 (a) T. Muraki, H. Togo and M. Yokoyama, Tetrahedron Lett., 1996,
37, 2441; (b) H. Togo, T. Muraki, Y. Hoshina, K. Yamaguchi and
M. Yokoyama, J. Chem. Soc., Perkin Trans. 1, 1997, 787; (c) R. L.
Dorta, A. Martín and E. Suárez, Tetrahedron: Asymmetry, 1996, 7,
1907; (d) C. G. Francisco, R. Freire, C. González and E. Suárez,
Tetrahedron: Asymmetry, 1997, 8, 1971; (e) R. Hernández, E. I.
León, P. Moreno and E. Suárez, J. Org. Chem., 1997, 62, 8974;
( f ) T. Gimisis, C. Castellari and C. Chatgilialoglu, Chem. Commun.,
1997, 2089; (g) P. de Armas, F. García-Tellado, J. J. Marrero-Tellado
and J. Robles, Tetrahedron Lett., 1997, 38, 8081; (h) C. G. Francisco,
C. G. Martín and E. Suárez, J. Org. Chem., 1998, 63, 2099; (i) R. L.
Dorta, A. Martín, J. A. Salazar and E. Suárez, J. Org. Chem., 1998,
63, 2251; (j) H. Togo, T. Muraki and M. Yokoyama, Tetrahedron
Lett., 1995, 36, 7089.
6 Nitrogen-centered radicals are also generated in this system; (a)
P. de Armas, R. Carrau, J. I. Concepción, C. G. Francosco, R.
Hernández and E. Suárez, Tetrahedron Lett., 1985, 26, 2493;
(b) R. Carrau, R. Hernández and E. Suárez, J. Chem. Soc., Perkin
Trans. 1, 1987, 937; (c) R. Hernández, M. C. Medina, J. A. Salazar,
E. Suárez and T. Prangé, Tetrahedron Lett., 1987, 28, 2533; (d)
P. de Armas, C. G. Francisco, R. Hernández, J. A. Salazar and
E. Suárez, J. Chem. Soc., Perkin Trans. 1, 1988, 3225; (e) R. L.
Dorta, C. G. Francisco and E. Suárez, J. Chem. Soc., Chem.
Commun., 1989, 1169; ( f ) H. Togo, Y. Hoshina and M. Yokoyama,
Tetrahedron Lett., 1996, 37, 6129; (g) H. Togo, M. Katohgi and
M. Yokoyama, Synlett, 1998, 131; (h) H. Togo, Y. Hoshina,
T. Muraki, H. Nakayama and M. Yokoyama, J. Org. Chem., 1998,
63, 5193.
7 o-Iodosylbenzoic acid and iodylbenzene were also used in the
Suárez system: P. de Armas, J. I. Concepción, C. G. Francisco,
R. Hernández, J. A. Salazar and E. Suárez, J. Chem. Soc., Perkin
Trans. 1, 1989, 405.
8 (a) I. Collins, J. Chem. Soc., Perkin Trans. 1, 1998, 1869; (b) D. M. X.
Donnelly and M. J. Meegan, Comprehensive Heterocyclic Chemistry;
ed. A. R. Katritzky, Pergamon, 1984, vol. 4, 657.
Benzo[c]chromen-6-one (3d). Mp 91.0–92.0 ЊC; IR (KBr)
1720, 1600, 1480, 1300, 900, and 730 cmϪ1 1H NMR (500
;
MHz, CDCl3) δ = 7.31–7.36 (2H, m, 2, 4-H), 7.46 (1H, tt,
J = 7.8, 1.2 Hz, 3-H), 7.56 (1H, td, J = 7.7, 1.2 Hz, Ar), 7.80
(1H, td, J = 7.7, 1.1 Hz, Ar), 8.03 (1H, dd, J = 7.8, 1.4 Hz, 1-
H), 8.09 (1H, d, J = 8.0 Hz, Ar), 8.38 (1H, dd, J = 7.9, 1.2 Hz,
Ar); 13C NMR (125 MHz, CDCl3) δ = 117.75 (t, 4-C), 118.02
(q, Ar), 121.23 (q, Ar), 121.67 (t, Ar), 122.76 (t, 1-C), 124.54 (t,
2-C), 128.86 (t, Ar), 130.42 (t, 3-C), 130.54 (t, Ar), 134.74 (q,
Ar), 134.83 (t, Ar), 151.27 (q, Ar), 161.16 (q, CO); Found: C,
79.63; H, 3.98%. Calcd. for C13H8O2: C, 79.58; H, 4.11%;
HRMS (FAB) Found: (M ϩ H)ϩ = 197.0610. Calcd. for C13H9-
O2: M ϩ H = 197.0603.
2-Iodobenzo[c]chromen-6-one (3d-i). Mp 148.0–149.0 ЊC; IR
1
(KBr) 3070, 1740, 1600, 1480, 1220, 1040, and 815 cmϪ1; H
NMR (500 MHz, CDCl3) δ = 7.12 (1H, d, J = 8.5 Hz, 4-H),
7.62 (1H, td, J = 7.6, 1.1 Hz, Ar), 7.74 (1H, dd, J = 8.5, 1.5 Hz,
3-H), 7.84 (1H, tt, J = 7.3, 0.6 Hz, Ar), 8.05 (1H, d, J = 7.9 Hz,
Ar), 8.34 (1H, d, J = 1.5 Hz, 1-H), 8.39 (1H, dd, J = 7.6, 0.6
Hz, Ar); 13C NMR (125 MHz, CDCl3) δ = 87.85 (q, 2-C),
119.80 (t, 4-C), 120.32 (q, Ar), 121.25 (q, Ar), 121.79 (t, Ar),
129.60 (t, Ar), 130.76 (t, Ar), 131.75 (t, 1-C), 133.35 (q, Ar),
135.09 (t, Ar), 139.07 (t, 3-C), 150.96 (q, Ar), 160.51 (q, CO);
Found: C, 48.13; H, 2.10%. Calcd. for C13H7O2I: C, 48.48; H,
2.19%; HRMS (FAB) Found: (M ϩ H)ϩ = 322.9562. Calcd. for
C13H8O2I: M ϩ H = 322.9569.
Acknowledgements
H. T. is grateful for financial support from a Grant-in-Aid for
Scientific Research (No. 10640511) from the Ministry of
Education, Science and Culture of Japan. The authors thank
Ms Ritsuko Hara for the measurement of high resolution mass
spectra and Dr Hiroko Seki for the measurement of elemental
analyses, in the Chemical Analysis Center of Chiba University.
9 T. Muraki, H. Togo and M. Yokoyama, Synlett, 1998, 286.
10 A. McKillop and D. Kemp, Tetrahedron, 1989, 45, 3299.
11 G. P. Baker, F. G. Mann, N. Sheppared and A. J. Tetlow, J. Chem.
Soc., 1965, 3721.
12 (a) V. V. Zhdankin, C. J. Kuehl, J. T. Bolz, M. S. Formaneck
and A. J. Simonsen, Tetrahedron Lett., 1994, 35, 7323; (b) V. V.
Zhdankin, C. J. Kuehl, A. P. Krasutsky, J. T. Bolz and A. J.
Simonsen, J. Org. Chem., 1996, 61, 6547.
References
1 Recent reviews: (a) T. Kitamura, Yuki Gosei Kagaku Kyoukaishi,
1995, 53, 893; (b) P. J. Stang and V. V. Zhdankin, Chem. Rev., 1996,
96, 1123; (c) T. Umemoto, Chem. Rev., 1996, 96, 1757; (d) Y. Kita,
T. Takada and H. Tohma, Pure Appl. Chem., 1996, 68, 627; (e) N. S.
Zefirov, Pure Appl. Chem., 1996, 68, 881; ( f ) H. Togo, Y. Hoshina,
G. Nogami and M. Yokoyama, Yuki Gosei Kagaku Kyoukaishi,
1997, 55, 90; (g) A. Varvoglis, Tetrahedron, 1997, 53, 1179; (h) V. V.
Zhdankin, Rev. Heteroatom Chem., 1997, 17, 133; (i) T. Muraki,
H. Togo and M. Yokoyama, Rev. Heteroatom Chem., 1997, 17, 213;
Paper 9/00791A
1716
J. Chem. Soc., Perkin Trans. 1, 1999, 1713–1716