Checked by Willi-Kurt Gries and Larry E. Overman.
1. Procedure
B.
2-(Phenylsulfonyl)-1,3-cyclohexadiene. A
1-L, one-necked, round-bottomed flask, equipped with a magnetic stirring bar, is charged with
53.0 g (116 mmol) of trans-3-(phenylsulfonyl)-4-(chloromercuri)cyclohexene and
600 mL of diethyl ether (Note
6) at room temperature. The slurry is stirred for 5 min (Note
7) and
175 mL (350 mmol) of a 2 M aqueous solution of sodium hydroxide is added under vigorous stirring (Note
8). The reaction mixture immediately turns black and the vigorous stirring is continued for 30 min (Note
9). The two layers are separated and the aqueous phase is extracted three times with
50-mL portions of diethyl ether. The combined organic layers are filtered through a
short column containing
10 g of silica gel and the column is washed with
250 mL of diethyl ether. The ethereal solution is dried over anhydrous
magnesium sulfate and filtered, and the solvent is removed at reduced pressure using a
rotary evaporator to give
22.5–24.5 g (
88–96%) of
2-(phenylsulfonyl)-1,3-cyclohexadiene as a colorless solid (Note
10).
2. Notes
1.
Mercury(II) chloride was purchased from Merck & Company, Inc. and used as delivered. The checkers used material purchased from Mallinckrodt Inc.
3.
1,3-Cyclohexadiene was obtained from Fluka Chemical Corporation and distilled before use. The distillation was performed at ambient temperature and reduced pressure (60–70 mm) and the diene was collected in a flask cooled with liquid
nitrogen. The checkers used
diene purchased from Aldrich Chemical Company, Inc.
4. A funnel with a fine frit must be used.
5. The crude product melts at
119–123°C and is sufficiently pure for use in the next step. Recrystallization from
ethyl acetate provides material melting at
128°C (dec). NMR spectral properties are as follows:
1H NMR (250 MHz, CDCl
3) δ: 1.92–2.12 (m, 3 H), 2.36–2.51 (m, 1 H), 2.95–3.05 (m, 1 H, H-4), 4.24–4.34 (m, 1 H, H-3), 5.57–5.81 (m, 1 H, =CH), 6.04–6.16 (m, 1 H, =CH), 7.53–7.65 (m, 3 H, ArH), 7.82–7.87 (m, 2 H, ArH);
13C NMR (75 MHz/CDCl
3) δ: 26.5, 26.7, 44.1, 66.2, 119.6, 129.1, 129.3, 134.2, 135.4, 136.6.
6. The submitters report that
dichloromethane can be used also as the solvent with similar results. This modification was not checked.
9. The submitters report that if
dichloromethane is used as solvent, the reaction mixture is stirred for 1.5 hr.
10. The crude product melts at
60–63°C. The spectral properties of
2-(phenylsulfonyl)-1,3-cyclohexadiene are as follows: IR (KBr) cm
−1: 3060, 2982, 2923, 2880, 2830, 1585, 1450, 1305, 1150, 1090, 710, 690;
1H NMR (250 MHz/CDCl
3) δ: 2.11–2.21 (m, 2 H), 2.35–2.45 (m, 2 H), 5.90–5.97 (m, 1 H, H-4), 6.07 (ddd, 1 H,
J = 9.9, 3.6, 1.8, H-3), 6.91–6.95 (m, 1 H, H-1), 7.47–7.62 (m, 3 H, ArH), 7.84–7.88 (m, 2 H, ArH);
13C NMR (75 MHz/CDCl
3) δ: 20.7, 22.3, 118.4, 127.7, 129.1, 130.0, 133.2, 134.8, 138.6, 139.8.
3. Discussion
This procedure
2,3;
4 illustrates a highly selective and facile method for introducing a phenylsulfonyl group into the 2-position of 1,3-diene systems by using commercially available starting materials. The method can be applied to cyclic as well as acyclic systems giving
2-(phenylsulfonyl)-1,3-dienes. In an alternative synthesis
5;
6 via condensation of
allyl sulfone with aldehyde and subsequent acylation–elimination, the
2-(phenylsulfonyl)-1,3-dienes obtained are limited to acyclic systems.
The procedure described has been applied
2 to
4-methyl-1,3-pentadiene,
1,3-pentadiene and
1,3-butadiene (Table I). Caution must be taken in the handling of the
sulfonyldiene products from the two latter dienes. They must be handled and stored in solution since they readily undergo Diels–Alder dimerization when concentrated. For the preparation of
2-(phenylsulfonyl)-1,3-pentadiene, final removal of solvent is never effected, giving a 10–50 m
M solution of product in the preferred solvent. The solution can be stored at −20°C for several days (<5% dimerization), but the product was usually used within a few hours.
Phenylsulfonyl-1,3-dienes are versatile synthetic intermediates. They can participate in cycloaddition reactions and Michael-type additions
3,4,7 8, leading to adducts which can be further functionalized.
3,4,7,8 In the latter case the resulting allylic sulfone can be functionalized by electrophiles, nucleophiles, or both:
Electron-deficient 1,3-dienes are potentially interesting Diels–Alder dienes. In our study with different kinds of olefins, we observed that 2-(phenylsulfonyl)-1,3-dienes show a duality in their Diels–Alder cycloaddition reactions, giving [4+2] adducts with both electron-deficient and electron-rich olefins.
3,4 This dual reactivity of the 2-(phenylsulfonyl)-1,3-dienes in [4+2] cycloaddition increases the role they can play in organic synthesis.
Appendix
Compounds Referenced (Chemical Abstracts Registry Number)
2-(phenylsulfonyl)-1,3-dienes
Phenylsulfonyl-1,3-dienes
calcium chloride (10043-52-4)
ethyl acetate (141-78-6)
diethyl ether (60-29-7)
sodium hydroxide (1310-73-2)
nitrogen (7727-37-9)
acetone (67-64-1)
mercury(II) chloride (7487-94-7)
dichloromethane (75-09-2)
magnesium sulfate (7487-88-9)
1,3-Butadiene (106-99-0)
sulfonyldiene,
Sulfonyl Diene
4-methyl-1,3-pentadiene (926-56-7)
1,3-pentadiene (504-60-9)
dimethyl sulfoxide (67-68-5)
1,3-Cyclohexadiene (592-57-4)
sodium benzenesulfinate,
benzenesulfinic acid, sodium salt
2-(Phenylsulfonyl)-1,3-cyclohexadiene,
Benzene, (1,5-cyclohexadien-1-ylsulfonyl)- (102860-22-0)
allyl sulfone
2-(phenylsulfonyl)-1,3-pentadiene
trans-3-(Phenylsulfonyl)-4-(chloromercuri)cyclohexene
Copyright © 1921-2002, Organic Syntheses, Inc. All Rights Reserved