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Synlett 2010(15): 2325-2329  
DOI: 10.1055/s-0030-1258017
LETTER
© Georg Thieme Verlag Stuttgart ˙ New York

An Efficient Preparation of Chroman Derivatives from 3-Aryl-1-propanols and Related Compounds with 1,3-Diiodo-5,5-dimethylhydantoin under Irradiation Conditions

Shusuke 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;
Further Information

Publication History

Received 3 June 2010
Publication Date:
06 August 2010 (online)

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Abstract

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.

Key words

1,3-diiodo-5,5-dimethylhydantoin - 3-aryl-1-propanol - chroman - alkoxyl radical - cyclization - aroyloxyl radical

11

Typical Procedure for Preparation of Chromane from 3-Phenyl-1-propanol with DIH 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 reaction, the mixture was poured into a sat. aq Na2SO4 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.
Chromane
Oil. IR (neat): 2935, 2861, 1581, 1488, 1227, 1115 cm-¹. ¹H NMR (400 MHz, CDCl3, TMS): δ = 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): δ = 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.
6-Iodochromane Oil. IR (neat): 2900, 2850, 1560, 1480, 1230, 1120, 810 cm-¹. ¹H NMR (400 MHz, CDCl3, TMS): δ = 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): δ = 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.
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): δ = 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): δ = 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 Oil. ¹H NMR (400 MHz, CDCl3, TMS): δ = 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): δ = 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. 2-Ethyl-6-iodochromane Oil. ¹H NMR (400 MHz, CDCl3, TMS): δ = 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): δ = 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. 2-Butyl-6-iodochromane Oil. IR (neat): 2900, 2830, 1560, 1470, 1240, 1120, 820 cm-¹. ¹H NMR (400 MHz, CDCl3, TMS): δ = 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 H), 2.79 (ddd, J = 16.7, 10.6, 5.1 Hz, 1 H), 3.94 (tdd, 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): δ = 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 Oil. IR (neat): 2950, 2900, 1560, 1470, 1260, 1220, 1160, 1120, 820 cm-¹. ¹H NMR (400 MHz, CDCl3, TMS): δ = 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): δ = 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 Oil. H NMR (400 MHz, CDCl3, TMS): δ = 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): δ = 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).
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): δ = 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): δ = 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.
3-Methylphthalide Oil. IR (neat): 2940, 1740, 1590, 1450, 1210, 1030, 760, 740 cm-¹. ¹H NMR (400 MHz, CDCl3, TMS): δ = 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): δ = 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.
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): δ = 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.
6,6-Dimethyl-6 H -dibenzo[ b , d ]pyran Oil. ¹H NMR (400 MHz, CDCl3): δ = 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): δ = 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.