M. P. Coogan et al. / Tetrahedron 59 (2003) 7389–7395
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in benzene (70 mL) at 58C under an atmosphere of nitrogen.
The reaction mixture was stirred at reflux for 4 days and the
progress was monitored by TLC (Rf (40% diethyl ether/light
petroleum) 0.6). On completion, the reaction mixture was
quenched by the dropwise addition of methanol (3 mL) at
08C. The resulting suspension was separated between ethyl
acetate (100 mL) and water (50 mL), washed with saturated
sodium hydrogen carbonate solution (2£50 mL), dried over
magnesium sulfate and concentrated to give a dark oil. The
product was purified by short path distillation under high
vacuum to give the title compound 3 (5.64 g, 94%) as a
colourless oil, bp 86–898C (1.0 mm Hg); nmax/cm21 (NaCl
plate) 3147–2931, 1672, 1598; dH (400 MHz, CDCl3) 8.05
(1H, d, J¼7.6 Hz, ArH), 7.45 (1H, dd, J¼7.6, 7.6 Hz, ArH),
7.30 (1H, dd, J¼7.6, 7.6 Hz, ArH), 7.22 (1H, d, J¼7.6 Hz,
ArH), 2.98 (2H, t, J¼6.3 Hz, ArCH2), 1.98 (2H, t,
J¼6.3 Hz, CH2), 1.14 (6H, s, 2£CH3); dC (100 MHz,
CDCl3) 204.0, 142.8, 132.5, 130.7, 128.1, 127.3, 126.0,
41.0, 35.9, 25.1, 23.7; m/z (APCI) 175.1 (MHþ); HRMS
(ES): MHþ, found 175.1124. C12H15O requires 175.1123.
pound (2)-6 (0.41 g, 75%) as a colourless solid, mp 111–
1128C; [a]2D0¼250.9 (c 0.2, CHCl3); nmax/cm21 (NaCl
plate) 3482–2926, 1682, 1590, 1270; dH (400 MHz, CDCl3)
7.86 (1H, d, J¼7.6 Hz, ArH), 7.48 (2H, m, ArH), 7.39 (1H,
m, ArH), 4.00 (1H, d, J¼4.0 Hz, ArCH), 3.52 (1H, d,
J¼4.0 Hz, CH), 1.45 (3H, s, CH3), 1.06 (3H, s, CH3); dC
(100 MHz, CDCl3) 200.7, 138.7, 133.6, 130.9, 130.0, 129.9,
128.9, 61.4, 53.1, 43.8, 24.0, 21.8; m/z (APCI) 189.1
(MHþ); HRMS (CI, NH3): MNHþ4 , found 206.1181.
C12H16N1O2 requires 206.1182.
4.1.4. (6)-2,2-Dimethyl-1a,7b-dihydro-2H-1-oxacyclo-
propa[a]naphthalene-3-one (6)-6. A solution of 5
(209 mg, 1.21 mmol) in dichloromethane (3 mL) was
cooled to 08C under nitrogen. The solution was treated
with meta-chloroperoxybenzoic acid (50%, 448 mg,
1.3 mmol) in one portion and allowed to warm to room
temperature overnight. When the reaction was complete by
TLC (Rf (40% dichloromethane/light petroleum) 0.3) the
reaction mixture was extracted with diethyl ether
(2£20 mL), washed with sodium bicarbonate solution
(2£10 mL), water (10 mL) and brine (10 mL), dried over
magnesium sulfate and concentrated to give a colourless oil.
The product was purified by flash column chromatography
(40% dichloromethane/light petroleum) to give the title
compound (^)-6 (213 mg, 94%), which was identical to an
authentic sample. GC-FID analysis on a chiral stationary
phase with a chrompack column (CP7532): injection/
detection 2508C/3008C isothermal, separated an authentic
racemic sample (t1¼41.7 min; t2¼41.9 min).
4.1.2. 2,2-Dimethyl-2H-naphthalen-1-one (5). A mixture
of 3 (1 g, 5.74 mmol), N-bromosuccinimide (1.07 g,
6.03 mmol) and benzoyl peroxide (14.5 mg, 0.06 mmol) in
carbon tetrachloride (10 mL) was stirred at reflux for 5 h.
The reaction mixture was then filtered through a sinter,
washed with dichloromethane and reduced. The crude
product was treated with 10% potassium hydroxide in
ethanol (10 mL) and the mixture was stirred at 458C for 6 h,
the progress of the reaction being monitored by TLC (Rf
(30% dichloromethane/light petroleum) 0.7). The crude
reaction mixture was separated between diethyl ether
(15 mL) and water (15 mL) and washed with saturated
sodium bicarbonate solution (15 mL). After drying over
MgSO4, the product was concentrated to give an orange oil.
The crude material was purified by vacuum distillation to
give the title compound 5 (0.90 g, 89%) as a colourless oil,
bp 87–898C (0.5 mm Hg); nmax/cm21 (NaCl plate) 3496–
2925, 1681, 1643; dH (400 MHz, CDCl3) 7.98 (1H, d,
J¼7.5 Hz, ArH), 7.48 (1H, dd, J¼7.5, 7.5 Hz, ArH), 7.27
(1H, dd, J¼7.5, 7.5 Hz, ArH), 7.15 (1H, d, J¼7.5 Hz, ArH),
6.43 (1H, d, J¼9.7 Hz, ArCH), 6.03 (1H, d, J¼9.7 Hz, CH),
1.19 (6H, s, 2£CH3); dC (100 MHz, CDCl3) 204.0, 141.6,
138.8, 134.7, 131.8, 128.1, 127.6, 127.5, 122.9, 45.6, 26.3;
m/z (APCI) 173.2 (MHþ); HRMS (ES): MHþ, found
173.0965. C12H13O requires 173.0965.
4.1.5. (2)(1R,3R)-2,2-Dimethyl-1,2,3,4-tetrahydro-
naphthalene-1,3-diol (2)-1. To 10% Pd/C catalyst
(35 mg) was added
a solution of (2)-6 (350 mg,
1.86 mmol) in ethyl acetate (3 mL) and methanol (75 mL,
1.86 mmol). The reaction mixture was stirred under an
atmosphere of hydrogen for 10 min. On completion by TLC
(Rf (40% diethyl ether/light petroleum) 0.1) the reaction
mixture was filtered through Celitew and concentrated to
give an orange oil. The crude reaction mixture was then
stirred with di-isobutylaluminium hydride (1 M in hexanes,
4.74 mL, 4.74 mmol) in tetrahydrofuran (10 mL) at 2788C
for 30 min. After quenching with hydrochloric acid (2N,
5 mL) the organic phase was partitioned between diethyl
ether (10 mL) and water (10 mL) and the organic phase was
washed with sodium bicarbonate solution (10 mL), dried
over magnesium sulfate and concentrated under reduced
pressure. Purification of the crude product by flash column
chromatography (40% diethyl ether/light petroleum) gave
the title compound (2)-1 (267 mg, 75 %) as a colour-
less solid, mp 64.4–65.48C; [a]2D0¼277.0 (c 0.2, CHCl3);
4.1.3. (2)-(3S,4R)2,2-Dimethyl-1a,7b-dihydro-2H-1-oxa-
cyclopropa[a]naphthalene-3-one (2)-6. 0 A solution of 5
(0.5 g, 2.91 mmol) and (R,R)-(2)-N,N -bis-(3,5-di-tert-
butylsalicylidene)-1,2-cyclohexanediamino-manganese(III)
chloride (92 mg, 0.15 mmol) in dichloromethane (10 mL)
was stirred at 08C for 5 min. A buffer solution of NaHPO4
(0.05 M, 5.8 mL) and NaOCl (4.5%, 9.7 mL) stirring at 08C
(pH 11) was then added and the reaction mixture was stirred
at 08C for 3 days. After the reaction was complete by TLC
(Rf (40% dichloromethane/light petroleum) 0.3) brine
(50 mL) was added to the reaction mixture and the aqueous
phase was extracted with dichloromethane (3£50 mL). The
combined organic extracts were dried over magnesium
sulfate, filtered and concentrated to give a dark oil which
was purified by flash column chromatography (40%
dichloromethane/light petroleum) to give the title com-
n
max/cm21 (NaCl plate) 3650–3200, 3391–2931; dH
(400 MHz, CDCl3) 7.33 (1H, m, ArH), 7.19 (2H, m,
ArH), 7.08 (1H, m, ArH), 4.21 (1H, s, ArCHOH), 3.83 (1H,
dd, J¼3.9, 4.6 Hz, ArCHH), 3.08 (1H, dd, J¼17.7, 4.6 Hz,
ArCHH), 2.89 (1H, dd, J¼17.7, 3.9 Hz, ArCH2CHOH),
2.51 (2H, s, 2£OH), 1.19 (3H, s, CH3), 0.88 (3H, s, CH3); dC
(100 MHz, CDCl3) 138.0, 132.2, 130.3, 129.7, 128.4, 127.1,
77.3, 75.0, 38.2, 35.8, 24.2, 21.1; m/z (APCI) 193.1 (MHþ);
HRMS (EI): MHþ, found 192.1149. C12H16O2 requires
192.1150.
Crystal data. C12H16O2, crystallises from diethyl ether/light