An efficient preparation of chroman derivatives from 3-aryl-1-propanols and related compounds with 1,3-diiodo-5,5-dimethylhydantoin under irradiation conditions

Article abstract of DOI:10.1055/s-0030-1258017

Treatment of various 3-aryl-1-propanols with 1,3-diiodo-5,5- dimethylhydantoin (DIH) in ethyl acetate or 1,2-dichloroethane under irradiation with a tungsten lamp gave the corresponding chroman derivatives in good to moderate yields. The present reaction proceeds via the initial formation of an alkoxyl radical and the radical cyclization onto the aromatic ring, followed by the oxidation of the formed radical intermediate with DIH to provide the chroman derivative. The same treatment of o-biphenyldimethylcarbinol, o-phenylbenzoic acid, and o-alkylbenzoic acids with DIH provided the corresponding chroman derivatives and lactone derivatives in good yields, respectively. Georg Thieme Verlag Stuttgart - New York.

Full text of DOI:10.1055/s-0030-1258017

LETTER
2325
An Efficient Preparation of Chroman Derivatives from 3-Aryl-1-propanols
and Related Compounds with 1,3-Diiodo-5,5-dimethylhydantoin under
Irradiation Conditions
P
reparationof
h
C
hroma
n
D
e
u
rivative
s
suke Furuyama, Hideo Togo*
Graduate School of Science, Chiba University, Yayoi-cho 1-33, Inage-ku, Chiba 263-8522, Japan
E-mail: togo@faculty.chiba-u.jp
Received 3 June 2010
and molecular iodine system. As far as we know, the syn-
Abstract: Treatment of various 3-aryl-1-propanols with 1,3-di-
iodo-5,5-dimethylhydantoin (DIH) in ethyl acetate or 1,2-dichloro-
thetic studies of DIH are extremely limited. There is one
study where DIH was used for the iodination of aromatic
compounds.8 The chroman skeleton is a very important
unit and is contained in some natural products, such as vi-
tamin E and flavonoid compounds. Therefore, its synthet-
ic study is very attractive. An extensive study of the
preparation of the chroman skeleton has been carried out.9
ethane under irradiation with
a tungsten lamp gave the
corresponding chroman derivatives in good to moderate yields.
The present reaction proceeds via the initial formation of an alkoxyl
radical and the radical cyclization onto the aromatic ring, followed
by the oxidation of the formed radical intermediate with DIH to pro-
vide the chroman derivative. The same treatment of o-biphenyldi-
methylcarbinol, o-phenylbenzoic acid, and o-alkylbenzoic acids
with DIH provided the corresponding chroman derivatives and lac-
tone derivatives in good yields, respectively.
O
DIH :
N
I
Key words: 1,3-diiodo-5,5-dimethylhydantoin, 3-aryl-1-propanol,
chroman, alkoxyl radical, cyclization, aroyloxyl radical
N
I
O
Figure 1
The use of trivalent iodines for organic synthesis has been
studied widely.1 Among them, (diacetoxyiodo)benzene
(DIB) is the most popular and useful trivalent iodine re-
agent for organic synthesis and is used as an alternative to
toxic heavy-metal reagents.2 The advantages of DIB are
that it is a nonmetal oxidant and can be used not only for
polar reactions, but also for radical reactions to generate
oxygen-centered radicals, nitrogen-centered radicals, and
carbon-centered radicals.3 In radical reactions, the initial
formation of an unstable acetyl hypoiodite (MeCO2I)
from the reaction with DIB and molecular iodine is the
key step, and acetyl hypoiodite reacts with alcohols to
form alkyl hypoiodites that would serve as the precursors
of alkoxyl radicals.4,5 Synthetic studies of alkoxyl radicals
derived from substrates, such as steroidal alcohols and
sugars, with DIB and molecular iodine have been well
carried out by Suarez et al.3 We have also studied the syn-
thetic use of oxygen-centered radicals for the construction
of chromans from 3-aryl-1-propanols6 and nitrogen-cen-
tered radicals for the construction of tetrahydroquinolines,
benzosultams, and saccharins from sulfonamides7 with
DIB and molecular iodine under irradiation with a tung-
sten lamp. On the other hand, 1,3-diiodo-5,5-dimethyl-
hydantoin (DIH, Figure 1) is not a hypervalent iodine
compound, but it may work as a synthon of unstable
acetyl hypoiodite derived from the reaction with DIB and
molecular iodine. Thus, this suggests that the above reac-
tions can be carried out with DIH alone, instead of a DIB
Here, as part of our explorative work on the synthetic use
of DIH,10 we would like to report an efficient preparation
of the chroman skeleton from 3-aryl-1-propanols and re-
lated reactions with DIH under irradiation with a tungsten
lamp. Table 1 shows the results of the reaction of 3-phe-
nyl-1-propanol with DIH under irradiation with a tungsten
lamp (300 W) in ethyl acetate and 1,2-dichloroethane
(DCE). When the reaction was carried out in ethyl acetate,
chroman (2A-I) was obtained mainly (entries 1–6). In
contrast, 6-iodochroman (2A-II) was obtained mainly
when the reaction was carried out in DCE (entries 7, 8,
11–13).11 These results indicate that less polar solvents
than ethyl acetate, such as DCE, induce the 6-iodination
of the formed chromans. N-Iodosuccinimide (NIS) also
worked to give chroman in moderate yield (entry 9), al-
though 3.2 equivalents of NIS were required. When the
reaction was carried out in the presence of galvinoxyl free
radical under the same conditions, chromans were not
formed at all, and the starting 3-phenyl-1-propanol was
recovered quantitatively (entry 10). Thus, this result indi-
cates that the present reaction proceeds through the forma-
tion of radical species.
Based on these results, 1-methyl-, 1-ethyl-, 1-butyl-, 1,1-
dimethyl-, 1-dodecyl, and 1-tridecyl-3-phenyl-1-pro-
panols were treated with DIH in ethyl acetate and DCE to
provide the corresponding chroman derivatives in good to
moderate yields as shown in Table 2 (entries 1–11). Under
the same conditions, 3-(4¢-methylphenyl)-1-propanol and
3-(4¢-chlorophenyl)-1-propanol provided the correspond-
ing chroman derivatives in good to moderate yields (en-
SYNLETT 2010, No. 15, pp 2325–2329
x
x
.x
x
.2
0
1
0
Advanced online publication: 06.08.2010
DOI: 10.1055/s-0030-1258017; Art ID: U04910ST
© Georg Thieme Verlag Stuttgart · New York

2326
S. Furuyama, H. Togo
LETTER
Table 1 Preparation of Chroman from 3-Phenyl-1-propanol with DIH
X
DIH
OH
solvent, hν (W lamp)
O
1A
2A-I X = H
2A-II X = I
Entry
1
Solvent (mL)
EtOAc (10)
EtOAc (10)
EtOAc (10)
EtOAc (10)
EtOAc (10)
EtOAc (10)
DCE (10)
DIH (equiv)
1.0
Temp (°C)
Time (h)
Yield of 2A-I (%) Yield of 2A-II (%)
40
40
55
40
55
40
40
40
40
40
40
40
40
9
9
32
53
48
52
52
39
18
30
3
3
11
5
2
1.6
3
1.6
10
9
4
2.0
5
5
2.0
10
9
14
18
34
60
57
0
6
2.4
7
1.0
7
8
DCE (10)
1.6
7
9a
10b
11
12
13
DCE (10)
3.2
7
DCE (10)
1.6
7
0
DCE (15)
3.0
9
8
75
79
82
DCE (15)
3.5
9
7
DCE (15)
4.0
9
3
a Instead of DIH (1.6 mmol) NIS (3.2 mmol) was used.
b Reaction was carried out in the presence of galvinoxyl free radical (1 mmol).
tries 12–16). However, the same treatment of 3-(4¢- Alkyl hypoiodite a is formed by the reaction of 3-phenyl-
nitrophenyl)-1-propanol did not give the cyclized product 1-propanol (1A) with DIH. Homolytic O–I bond cleavage
at all (entry 17). These results suggest that the cyclization of hypoiodite a occurs to provide oxygen-centered radical
onto the aromatic ring by the oxygen-centered radical of b. Then, oxygen-centered radical b cyclizes onto the aro-
the formed alkoxyl radical proceeds in an electrophilic matic ring in an electrophilic manner to generate radical
manner. A plausible reaction mechanism is shown in intermediate c, which is further oxidized to chroman 2A-
Scheme 1.
I. Chroman 2A-I is iodinated at 6-position by DIH in an
electrophilic manner to give 6-iodochroman 2A-II.
hν (W lamp)
The same treatment of o-biphenyldimethylcarbinol (3)
with DIH under irradiation with a tungsten lamp generat-
ed corresponding benzochroman (4) in good yield, as
shown in Scheme 2.
DIH
OH
O
2A-I
1A
DIH
However, o-biphenylcarbinol and o-biphenylmethyl-
carbinol, which are primary and secondary alcohols, re-
spectively, gave the corresponding benzochromans in low
yields due to the formation of the corresponding aldehyde
and methylketone via the oxidation of the formed alkoxyl
radicals. Treatment of o-phenylbenzoic acid (5) and o-
alkylbenzoic acids 7 with DIH under irradiation with a
tungsten lamp provided the corresponding d-lactone 6 and
g-lactones 8 in good yields, respectively. A plausible re-
action mechanism for the formation of g-lactones 8 from
the reaction of o-alkylbenzoic acids 7 with DIH is shown
in Scheme 3. The initial formation of aroyl hypoiodite d
and the homolytic cleavage of the O–I bond occurs to pro-
vide aroyloxyl radical e. Then, the 1,5-H shift occurs to
form benzylic radical, which reacts with aroyl hypoiodite
DIH
I
O-I
(– e)
O
2A-II
(a)
(– H+)
DIH
(– I•)
O•
•
O
(b)
(c)
Scheme 1
Synlett 2010, No. 15, 2325–2329 © Thieme Stuttgart · New York

LETTER
Preparation of Chroman Derivatives
2327
Table 2 Preparation of Chroman Derivatives from 3-Aryl-1-propanols with DIH
R3
R2
X
DIH
OH
R2
R3
solvent (10 mL)
O
R1
hν (W lamp), 40 °C, 9 h
R1
1
2-I X = H
2-II X = I
Entry
1
R1
H
R2
H
R3
DIH (equiv)
1.6
Solvent
EtOAc
DCE
Yield of 2-I (%) Yield of 2-II (%)
Me
Me
Et
50
14
46
58
11
37
21
19
8
6
64
2
2
H
H
2.5
3
H
H
1.6
EtOAc
DCE
4
H
H
Et
1.6
24
57
3
5
H
H
Et
2.5
DCE
6
H
H
Bu
Bu
Me
Me
1.6
EtOAc
DCE
7
H
H
2.5
21
41
29
1
8
H
Me
Me
H
1.6
DCE
9
H
2.5
DCE
10
11
12
13
14
15
16
17
18
H
n-C12H25
1.6
DCE
22
27
30
40
26
12
41
0
H
H
n-C12H25
2.5
DCE
7
Me
Me
Me
Cl
Cl
NO2
Me
H
H
1.6
EtOAc
DCE
28
39
40
3
H
H
1.6
H
H
2.5
DCE
H
H
1.6
EtOAc
DCE
H
H
1.6
19
0
H
H
1.6
EtOAc
DCE
H
Me
2.5
31
20
d to generate benzylic iodide g and aroyloxyl radical e
again. Finally, the ionic cyclization of o-(a-iodo)alkyl-
benzoic acid occur to provide g-lactone 8.
References and Notes
(1) Varvoglis, A. Hypervalent Iodine in Organic Synthesis;
Academic Press: San Diego, 1997.
(2) Reviews: (a) Moriarty, R. M.; Vaid, R. K. Synthesis 1990,
431. (b) Stang, P. J. Angew. Chem., Int. Ed. Engl. 1992, 31,
274. (c) Prakash, O.; Saini, N.; Sharma, P. K. Synlett 1994,
221. (d) Kitamura, T. Yuki Gosei Kagaku Kyokaishi 1995,
53, 893. (e) Stang, P. J.; Zhdankin, V. V. Chem. Rev. 1996,
96, 1123. (f) Umemoto, T. Chem. Rev. 1996, 96, 1757.
(g) Kita, Y.; Takada, T.; Tohma, H. Pure Appl. Chem. 1996,
68, 627. (h) Togo, H.; Hoshina, Y.; Nogami, G.; Yokoyama,
M. Yuki Gosei Kagaku Kyokaishi 1997, 55, 90.
In conclusion, treatment of 3-aryl-1-propanols with 1,3-
diiodo-5,5-dimethylhydantoin (DIH) in ethyl acetate or
1,2-dichloroethane under irradiation with a tungsten lamp
provided the corresponding chroman derivatives in good
to moderate yields. The same treatment of o-biphenyldi-
methylcarbinol, o-phenylbenzoic acid, and o-alkylbenzo-
ic acids with DIH gave the corresponding chroman
derivatives and lactone derivatives, respectively, in good
yields.
(i) Varvoglis, A. Tetrahedron 1997, 53, 1179. (j) Zhdankin,
V. V. Rev. Heteroat. Chem. 1997, 17, 133. (k) Muraki, T.;
Togo, H.; Yokoyama, M. Rev. Heteroat. Chem. 1997, 17,
213. (l) Kitamura, T.; Fujiwara, Y. Org. Prep. Proced. Int.
1997, 29, 409. (m) Varvoglis, A.; Spyroudis, S. Synlett
1998, 221. (n) Zhdankin, V. V.; Stang, P. J. Tetrahedron
1998, 54, 10927. (o) Moriarty, R. M.; Prakash, O. Adv.
Heterocycl. Chem. 1998, 69, 1. (p) Togo, H.; Katohgi, M.
Synlett 2001, 565. (q) Zhdankin, V. V.; Stang, P. J. Chem.
Rev. 2002, 102, 2523. (r) Richardson, R. D.; Wirth, T.
Angew. Chem. Int. Ed. 2006, 45, 4402. (s) Ladziata, U.;
Acknowledgment
Financial support in the form of a Grant-in-Aid for Scientific Rese-
arch (20550033) from the Ministry of Education, Culture, Sports,
Science, and Technology in Japan, Academia Showcase Research
Grant from the Japan Chemical Innovation Institute (JCII), and
Iodine Research Project in Chiba University is gratefully acknowl-
edged.
Synlett 2010, No. 15, 2325–2329 © Thieme Stuttgart · New York

2328
S. Furuyama, H. Togo
LETTER
Suarez, E.; Rodriguez, M. S. J. Org. Chem. 1994, 59, 6395.
(f) Lee, J.; Oh, J.; Jin, S. J.; Choi, J. R.; Atwood, J. L.; Cha,
J. K. J. Org. Chem. 1994, 59, 6955. (g) Boto, A.; Betancor,
C.; Prange, T.; Suarez, E. J. Org. Chem. 1994, 59, 4393.
(h) Hernandez, R.; Suarez, E. J. Org. Chem. 1994, 59, 2766.
(i) Francisco, C. G.; Freire, R.; Rodriguez, M. S.; Suarez, E.
Tetrahedron Lett. 1995, 36, 2141. (j) Hernandez, R.;
Velazquez, S. M.; Suarez, E. Tetrahedron Lett. 1996, 37,
6409. (k) Francisco, C. G.; Gonzalez, C. C.; Suarez, E.
Tetrahedron Lett. 1996, 37, 1687. (l) Hernandez, R.; Leon,
E. I.; Moreno, P.; Suarez, E. J. Org. Chem. 1997, 62, 8974.
(m) Francisco, C. G.; Freire, R.; Gonzalez, C. C.; Suarez, E.
Tetrahedron: Asymmetry 1997, 8, 1971. (n) de Armas, P.;
García-Tellado, F.; Marrero-Tellado, J. J.; Robles, J.
Tetrahedron Lett. 1997, 38, 8081. (o) Boto, A.; Hernandez,
R.; Velazquez, S. M.; Suarez, E. J. Org. Chem. 1998, 63,
4697. (p) Francisco, C. G.; Martin, C. G.; Suarez, E. J. Org.
Chem. 1998, 63, 8092. (q) Francisco, C. G.; Martin, C. G.;
Suarez, E. J. Org. Chem. 1998, 63, 2099. (r) Khan, N.;
Cheng, X.; Mootoo, D. R. J. Am. Chem. Soc. 1999, 121,
4918. (s) Adinolfi, M.; Barone, G.; Iadonisi, A. Synlett 1999,
65. (t) Wipf, P.; Mareska, D. A. Tetrahedron Lett. 2000, 41,
4723.
DIH (1.0 equiv)
O
DCE, hν (W lamp),
OH
R1 R2
55°C, 7 h
R1
R2
4
3
R1 = R2 = H
15%
1 = H, R2 = Me 16%
1 = R2 = Me
R
R
87%
DIH
DCE, hν (W lamp),
O
R
55°C, 7 h
CO2H
O
5
6
DIH (1.1 equiv)
DIH (1.6 equiv)
92%
94%
R
DIH (1.0 equiv)
O
(4) (a) Ogata, Y.; Aoki, K. J. Am. Chem. Soc. 1968, 90, 6187.
(b) Merkushev, E. B.; Simakhina, N. D.; Koveshnikova,
G. M. Synthesis 1980, 486.
(5) Courtneidge, J. L.; Lusztyk, J.; Page, D. Tetrahedron Lett.
1994, 35, 1003.
(6) (a) Muraki, T.; Togo, H.; Yokoyama, M. Tetrahedron Lett.
1996, 37, 2441. (b) Togo, H.; Muraki, T.; Hoshina, Y.;
Yamaguchi, K.; Yokoyama, M. J. Chem. Soc., Perkin Trans.
1 1997, 787.
(7) (a) Togo, H.; Katohgi, M.; Yokoyama, M. Synlett 1998,
131. (b) Togo, H.; Hoshina, Y.; Muraki, T.; Nakayama, H.;
Yokoyama, M. J. Org. Chem. 1998, 63, 5193. (c) Katohgi,
M.; Togo, H.; Yamaguchi, K.; Yokoyama, M. Tetrahedron
1999, 55, 14885. (d) Togo, H.; Nabana, T.; Yokoyama, M.
J. Org. Chem. 2000, 65, 8391. (e) Togo, H.; Harada, Y.;
Yokoyama, M. J. Org. Chem. 2000, 65, 926.
DCE, hν (W lamp),
55°C, 7 h
CO2H
O
7
8
R = Me
R = Ph
66%
69%
Scheme 2
R
R
DIH
O
DCE, hν (W lamp)
CO2H
O
7
8
(8) Orazi, O. O.; Corral, R. A.; Bertorello, H. E. J. Org. Chem.
DIH
(– HI)
R
1965, 30, 1101.
(9) (a) Booth, S. E.; Jenkins, P. R.; Swain, C. J.; Sweeney, J. B.
J. Chem. Soc., Perkin Trans. 1 1994, 3499. (b) Larock, R.
C.; Yum, E. K.; Doty, M. J.; Sham, K. K. C. J. Org. Chem.
1995, 60, 3270. (c) Deshpande, P. P.; Tagliaferri, F.;
Victory, S. F.; Yan, S.; Baker, D. C. J. Org. Chem. 1995, 60,
2964. (d) Deshpande, P. P.; Baker, D. C. Synthesis 1995,
707. (e) Kuwabe, S.; Torraca, K. E.; Buchwald, S. L. J. Am.
Chem. Soc. 2001, 123, 12202. (f) Koufaki, M.; Detsi, A.;
Theodorou, E.; Kiziridi, C. Bioorg. Med. Chem. 2004, 12,
4835. (g) Shi, Z.; He, C. J. Am. Chem. Soc. 2004, 126,
13596. (h) Niu, J.; Guo, P.; Kang, J.; Li, Z.; Xu, J.; Hu, S.
J. Org. Chem. 2009, 74, 5075. (i) Zhang, L.; Zhang, W.;
Liu, J.; Hu, J. J. Org. Chem. 2009, 74, 2850.
R
I
O-I
C
O
CO2H
(d)
(g)
(d)
(– I•)
R
R
(e)
•
1,5-H shift
(10) (a) Iida, S.; Togo, H. Synlett 2007, 407. (b) Iida, S.; Togo,
H. Tetrahedron 2007, 63, 8274. (c) Takahashi, S.; Togo, H.
Synthesis 2009, 2329. (d) Moroda, A.; Furuyama, S.; Togo,
H. Synlett 2009, 1336. (e) Iida, S.; Ohmura, R.; Togo, H.
Tetrahedron 2009, 65, 6257. (f) Baba, H.; Togo, H.
Tetrahedron Lett. 2010, 51, 2063.
O•
CO2H
C
O
(e)
(f)
Scheme 3
(11) Typical Procedure for Preparation of Chromane from 3-
Zhdankin, V. Synlett 2007, 527.
Phenyl-1-propanol with DIH
(3) Review: (a) Togo, H.; Katohgi, M. Synlett 2001, 565.
Recent papers: (b) Boto, A.; Betancor, C.; Suarez, E.
Tetrahedron Lett. 1994, 35, 5509. (c) Boto, A.; Betancor,
C.; Suarez, E. Tetrahedron Lett. 1994, 35, 6933.
1,2-Dichloroethane (15 mL) was added to the mixture of
3-phenyl-1-propanol (1.0 mmol, 136.2 mg) and DIH (1.6
mmol, 607.8 mg, commercially available from Tokyo Kasei
Co.). The mixture was irradiated with a tungsten lamp (300
W) at 40 °C for 9 h under an argon atmosphere. After the
(d) Arencibia, T.; Salazar, J. A.; Suarez, E. Tetrahedron Lett.
1994, 35, 7463. (e) Hernandez, R.; Velazquez, S. M.;
Synlett 2010, No. 15, 2325–2329 © Thieme Stuttgart · New York

LETTER
reaction, the mixture was poured into a sat. aq Na2SO4
Preparation of Chroman Derivatives
2329
H), 2.79 (ddd, J = 16.7, 10.6, 5.1 Hz, 1 H), 3.94 (tdd,
solution and extracted with CHCl3 (3 × 15 mL). The organic
layer was dried over Na2SO4. After filtration, the solvent was
removed under reduced pressure, and the residue was treated
with flash column chromatography on silica gel using a
mixture of hexane and EtOAc (1: 5) as an eluent to provide
chroman and 6-iodochroman.
J = 10.3, 5.5, 2.2 Hz, 1 H), 6.56 (d, J = 8.2 Hz, 1 H), 7.33 (d,
J = 8.2 Hz, 1 H), 7.34 (s, 1 H). 13C NMR (100 MHz, CDCl3,
TMS): d = 14.04 (p), 22.65 (s), 24.46 (s), 26.87 (s), 27.39
(s), 34.92 (s), 76.11 (t), 81.71 (q), 119.05 (t), 124.93 (q),
135.82 (t), 137.94 (t), 155.00 (q). HRMS (EI): m/z calcd for
C13H17OI [M]: 316.0324; found [M+]: 316.0323.
2,2-Dimethyl-6-iodochromane
Chromane
Oil. IR (neat): 2935, 2861, 1581, 1488, 1227, 1115 cm–1.
1H NMR (400 MHz, CDCl3, TMS): d = 1.98–2.04 (m, 2 H),
2.79 (t, J = 6.5 Hz, 2 H), 4.18 (t, J = 5.2 Hz, 2 H), 6.78 (d,
J = 8.1 Hz, 1 H), 6.83 (dd, J = 8.1, 7.5 Hz, 1 H), 7.03 (d,
J = 7.5 Hz, 1 H), 7.08 (dd, J = 7.5, 8.1 Hz, 1 H). 13C NMR
(100 MHz, CDCl3, TMS): d = 22.46 (s), 24.96 (s), 66.51 (s),
116.78 (t), 120.18 (t), 122.31 (q), 127.28 (t), 129.90 (t),
154.97 (q). HRMS (APPI): m/z calcd for C9H10O [M]:
134.0732; found [M+]: 134.0726.
Oil. IR (neat): 2950, 2900, 1560, 1470, 1260, 1220, 1160,
1120, 820 cm–1. 1H NMR (400 MHz, CDCl3, TMS): d = 1.31
(s, 6 H), 1.77 (t, J = 6.6 Hz, 2 H), 2.73 (t, J = 6.6 Hz, 2 H),
6.54 (d, J = 8.6 Hz, 1 H), 7.34 (d, J = 8.6 Hz, 1 H), 7.34 (s,
1 H). 13C NMR (100 MHz, CDCl3, TMS): d = 22.14 (s),
26.75 (p), 32.34 (s), 74.50 (q), 81.44 (q), 119.60 (t), 123.79
(q), 135.99 (t), 137.91 (t), 153.96 (q). HRMS (EI): m/z calcd
for C11H13OI [M]: 288.0011; found [M+]: 288.0027.
7-Methyl-6-iodochromane
6-Iodochromane
Oil. H NMR (400 MHz, CDCl3, TMS): d = 1.93–1.98 (m, 2
H), 2.32 (s, 3 H), 2.71 (t, J = 6.4 Hz, 2 H), 4.14 (t, J = 5.1 Hz,
2 H), 6.69 (s, 1 H), 7.44 (s, 1 H). 13C NMR (100 MHz,
CDCl3, TMS): d = 22.09 (s), 24.06 (s), 27.56 (p), 66.43 (s),
89.03 (q), 118.01 (t), 122.12 (q), 139.31 (t), 140.00 (q),
155.08 (q).
Oil. IR (neat): 2900, 2850, 1560, 1480, 1230, 1120, 810 cm–1.
1H NMR (400 MHz, CDCl3, TMS): d = 1.97 (tt, J = 6.4, 5.1
Hz, 2 H), 2.74 (t, J = 6.4 Hz, 2 H), 4.16 (t, J = 5.1 Hz, 2 H),
6.56 (d, J = 9.2 Hz, 1 H), 7.33 (d, J = 9.2 Hz, 1 H), 7.34 (s,
1 H). 13C NMR (100 MHz, CDCl3, TMS): d = 21.87 (s),
24.53 (s), 66.40 (s), 81.99 (q), 119.01 (t), 124.99 (q), 135.91
(t), 138.21 (t), 154.79 (q). HRMS (EI): m/z calcd for C9H9OI
[M]: 259.9698; found [M+]: 259.9689.
3,4-Benzocoumarin
Mp 91.0–92.0 °C. IR (KBr): 1720, 1600, 1480, 1300, 1205,
1100, 900, 760, 730 cm–1. 1H NMR (400 MHz, CDCl3,
TMS): d = 7.31–7.36 (m, 2 H), 7.47 (t, J = 7.7 Hz, 1 H), 7.57
(t, J = 8.0 Hz, 1 H), 7.81 (t, J = 8.0 Hz, 1 H), 8.04 (d, J = 7.7
Hz, 1 H), 8.10 (d, J = 8.0 Hz, 1 H), 8.39 (d, J = 8.0 Hz, 1 H).
13C NMR (100 MHz, CDCl3, TMS): d = 117.75 (t), 118.02
(q), 121.23 (q), 121.67 (t), 122.76 (t), 124.54 (t), 128.86 (t),
130.42 (t), 130.54 (t), 134.74 (q), 134.83 (t), 151.27 (q),
161.16 (q). HRMS–FAB: m/z calcd for C13H9O2 [M + H]:
197.0603; found [M + H]+: 197.0610.
2-Methyl-6-iodochromane
Mp 43.0–44.0 °C. IR (neat): 2920, 1550, 1460, 1240, 1110,
820 cm–1. 1H NMR (400 MHz, CDCl3, TMS): d = 1.38 (dd,
J = 6.2, 2.9 Hz, 3 H), 1.63–1.73 (m, 1 H), 1.97 (ddd,
J = 13.5, 7.5, 2.9 Hz, 1 H), 2.67–2.85 (m, 2 H), 4.07–4.13
(m, 1 H), 6.56 (d, J = 8.0 Hz, 1 H), 7.34 (d, J = 8.0 Hz, 1 H),
7.35 (s, 1 H). 13C NMR (100 MHz, CDCl3, TMS): d = 21.20
(p), 24.50 (s), 28.72 (s), 72.32 (t), 81.85 (q), 119.01 (t),
124.64 (q), 135.88 (t), 137.98 (t), 154.95 (q). HRMS (EI):
m/z calcd for C10H11OI [M]: 273.9855; found [M+]: 273.9840.
2-Ethylchromane
3-Methylphthalide
Oil. IR (neat): 2940, 1740, 1590, 1450, 1210, 1030, 760, 740
cm–1. 1H NMR (400 MHz, CDCl3, TMS): d = 1.64 (d,
J = 6.5 Hz, 3 H), 5.57 (q, J = 6.5 Hz, 1 H), 7.64 (d, J = 7.7
Hz, 1 H), 7.53 (t, J = 7.7 Hz, 1 H), 7.68 (t, J = 7.7 Hz, 1 H),
7.89 (d, J = 7.7 Hz, 1 H). 13C NMR (100 MHz, CDCl3,
TMS): d = 20.39 (p), 77.76 (t), 121.59 (t), 125.65 (t), 125.75
(q), 129.07 (t), 134.09 (t), 151.21 (q). HRMS–FAB: m/z
calcd for C9H9O2 [M + H]: 149.0603; found [M + H]+:
149.0627.
Oil. 1H NMR (400 MHz, CDCl3, TMS): d = 1.04 (t, J = 7.5
Hz, 3 H), 1.62–1.82 (m, 3H), 1.97–2.02 (m, 1 H), 2.75 (ddd,
J = 16.3, 5.7, 3.1 Hz, 1 H), 2.84 (ddd, J = 16.3, 11.3, 6.1 Hz,
1 H), 3.88–3.94 (m, 1 H), 6.80 (d, J = 7.9 Hz, 1 H), 6.81 (dd,
J = 7.9, 7.4 Hz, 1 H), 7.03 (d, J = 7.4 Hz, 1 H), 7.07 (dd,
J = 7.9, 7.4 Hz, 1 H). 13C NMR (100 MHz, CDCl3, TMS):
d = 9.65 (p), 24.80 (s), 26.84 (s), 28.28 (s), 77.16 (t), 116.70
(t), 119.84 (t), 122.10 (q), 127.10 (t), 129.48 (t), 155.11 (q).
HRMS (APCI): m/z calcd for C11H14O [M] 162.1039; found
[M+]: 162.1040.
3-Phenylphthalide
Mp 113.0–114.0 °C. IR (KBr): 3000, 1740, 1580, 1455,
1280, 1060, 970, 740 cm–1. 1H NMR (400 MHz, CDCl3,
TMS): d = 6.41 (s, 1 H), 7.27–7.40 (m, 6 H), 7.56 (t, J = 7.3
Hz, 1 H), 7.65 (t, J = 7.3 Hz, 1 H), 7.97 (d, J = 7.3 Hz, 1 H).
HRMS (EI): m/z calcd for C14H10O2 [M]: 210.0680; found
[M+]: 210.0678.
2-Ethyl-6-iodochromane
Oil. 1H NMR (400 MHz, CDCl3, TMS): d = 1.03 (t, J = 7.4
Hz, 3 H), 1.59–1.82 (m, 3 H), 1.94–2.00 (m, 1 H), 2.70 (ddd,
J = 16.6, 5.2, 3.4 Hz, 1 H), 2.75–2.83 (m, 1 H), 3.85–3.91
(m, 1 H), 6.57 (d, J = 8.0 Hz, 1 H), 7.33 (d, J = 8.6 Hz, 1 H),
7.34 (s, 1 H). 13C NMR (100 MHz, CDCl3, TMS): d = 9.71
(p), 24.58 (s), 26.50 (s), 28.26 (s), 77.45 (t), 81.82 (q),
119.16 (t), 125.06 (q), 135.96 (t), 138.06 (t), 155.15 (q).
HRMS (APCI): m/z calcd for C11H13OI [M]: 288.0006;
found [M+]: 288.0005.
6,6-Dimethyl-6H-dibenzo[b,d]pyran
Oil. 1H NMR (400 MHz, CDCl3): d = 1.64 (s, 6 H), 6.95 (d,
J = 8.2 Hz, 1 H), 7.02 (t, J = 7.5 Hz, 1 H), 7.20–7.36 (m, 4
H), 7.70–7.75 (m, 2 H). 13C NMR (100 MHz, CDCl3, TMS):
d = 27.68 (p), 77.63 (q), 118.15 (t), 121.62 (t), 122.32 (t),
122.57 (q), 122.97 (t), 123.30 (t), 127.79 (t), 128.04 (t),
128.69 (q), 129.52 (t), 139.61 (q), 152.85 (q). HRMS
(APCI): m/z calcd for C15H14O [M]: 210.1045; found [M+]:
210.1043.
2-Butyl-6-iodochromane
Oil. IR (neat): 2900, 2830, 1560, 1470, 1240, 1120, 820 cm–1.
1H NMR (400 MHz, CDCl3, TMS): d = 0.92 (t, J = 7.1 Hz,
3 H), 1.32–2.00 (m, 8 H), 2.70 (ddd, J = 16.7, 5.5, 3.3 Hz, 1
Synlett 2010, No. 15, 2325–2329 © Thieme Stuttgart · New York

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