(d, J = 8.0 Hz, 1H, ArH), 7.35 (t, J = 7.6 Hz, 1H, ArH), 7.60
(t, J = 7.6 Hz, 1H, ArH), 7.86 (dd, J = 7.8, 1.0 Hz, 1H, ArH)
ppm; 13C NMR (100 MHz, CD3COCD3): δ = 154.8, 143.0,
137.0, 133.4, 130.7, 130.4, 129.2, 129.0, 125.4, 124.7, 117.9,
44.9, 37.2, 28.9, 22.0 ppm.
50 : 20 : 30; flow rate 0.4 mL min−1; detection at 254 nm): minor
enantiomer tR = 13.2, major enantiomer tR = 18.9 min, 91% ee;
1
[α]2D5: +1.8 (c 1.0, CH2Cl2). H NMR (400 MHz, CD3SOCD3):
δ = 1.61 (s, 1.07H, CH3 ketal), 1.68 (s, 1.67H, CH3 ketal), 1.91
(t, J = 4.8 Hz, 0.65H, CH2), 2.14 (s, 0.28H, CH3 keto),
2.21–2.26 (m, 0.42H, CH2), 2.34–2.39 (m, 0.93H, CH2), 3.35
(s, 1H, CH), 4.17 (s, 1H ,OH), 7.38–7.67 (m, 5H, ArH), 7.85
(d, J = 6.8 Hz, 1H, ArH), 8.11 (t, J = 8.8 Hz, 2H, ArH) ppm;
13C NMR (100 MHz, CD3SOCD3): δ = 160.9, 160.3, 159.6,
159.3, 152.4, 152.33, 152.28, 145.8, 145.5, 132.2, 132.1, 128.8,
128.5, 124.1, 124.0, 123.4, 122.9, 122.7, 122.6, 116.3, 116.2,
115.4, 115.3, 102.3, 100.9, 100.8, 99.5, 41.8, 39.9, 35.2, 35.1,
27.1, 26.4 ppm.
(R)-3-[1-(4-Bromophenyl)-3-oxo-butyl]-4-hydroxychromen-2-one
(5g).17 Compound 5g was obtained according to the general pro-
cedure as a white solid (75.5 mg, 97% yield); mp 184–185 °C.
The enantiomeric excess was determined by HPLC with a
Daicel Chiralcel IA column (n-hexane–2-propanol–EtOAc
50 : 20 : 30; flow rate 0.5 mL min−1; detection at 254 nm): minor
enantiomer tR = 8.4, major enantiomer tR = 12.5 min, 96% ee;
1
[α]2D5: +1.4 (c 1.0, CH2Cl2). H NMR (400 MHz, CD3COCD3):
δ = 1.76 (s, 3H, CH3 ketal), 2.04–2.07 (m, 2H, CH2 ketal), 2.44
(s, 1H, CH ketal), 4.12 (s, 1H, OH ketal), 7.23–7.43 (m, 6H,
ArH), 7.62 (t, J = 7.6 Hz, 1H, ArH), 7.86 (d, J = 8.0 Hz, 1H,
ArH) ppm; 13C NMR (100 MHz, CD3COCD3): δ = 162.1,
160.8, 154.8, 145.6, 133.5, 133.0, 132.5, 131.7, 131.3, 125.5,
124.7, 120.9, 117.9, 105.6, 101.1, 44.5, 42.4, 37.1, 28.9 ppm.
(R)-3-(1-Furan-2-yl-3-oxo-butyl)-4-hydroxychromen-2-one
(5k).12a Compound 5k was obtained according to the general
procedure as a white solid (8.5 mg, 14% yield); mp 120–121 °C.
The enantiomeric excess was determined by HPLC with a
Daicel Chiralcel IA column (n-hexane–2-propanol–EtOAc
60 : 10 : 30; flow rate 0.5 mL min−1; detection at 254 nm): minor
enantiomer tR = 13.1, major enantiomer tR = 13.7 min, 99% ee;
(R)-3-[1-(2-Bromophenyl)-3-oxo-butyl]-4-hydroxychromen-2-one
(5h). Compound 5h was obtained according to the general pro-
cedure as a white solid (75.5 mg, 97% yield); mp 167–169 °C.
The enantiomeric excess was determined by HPLC with a
Daicel Chiralpak IA column (n-hexane–2-propanol–EtOAc
50 : 20 : 30; flow rate 0.5 mL min−1; detection at 254 nm): minor
enantiomer tR = 7.7, major enantiomer tR = 8.4 min, 93% ee;
[α]2D5: +9.0 (c 1.0, CH2Cl2). IR (KBr): ν 3786, 3696, 3453,
3050, 2989, 1689, 1624, 1575, 1393, 1189, 1176, 1070, 764,
1
[α]2D5: +6.5 (c 0.4, CH2Cl2). H NMR (400 MHz, CD3SOCD3):
δ = 1.56 (s, 1.42H, CH3 ketal), 1.60 (s, 0.74H, CH3 ketal),
2.11–2.21 (m, 1.68H, CH2 ketal + CH3 keto), 2.30 (dd, J = 6.4,
13.6 Hz, 0.62H, CH2 ketal), 2.39 (dd, J = 4.8, 14.0 Hz, 0.31H,
CH2 ketal), 3.28 (dd, J = 17.6, 7.6 Hz, 0.34H, CH2 keto), 3.41
(dd, J = 17.6, 6.8 Hz, 0.37H, CH2 keto), 4.08 (t, J = 5.6 Hz,
0.23 H, CH ketal), 4.14 (dd, J = 6.8, 9.6 Hz, 0.49H, CH ketal),
4.22 (t, J = 6.4 Hz, 0.14H, CH ketal), 4.97 (t, J = 7.0 Hz, 0.33H,
CH keto), 5.97 (d, J = 3.2 Hz, 0.18H, ArH), 6.09 (d, J = 3.2 Hz,
0.25H, CH), 6.16 (d, J = 2.8 Hz, 0.43H, ArH), 6.28–6.35 (m,
0.88H, ArH), 7.11 (s, 0.35H, OH ketal), 7.34–7.47 (m, 3H,
ArH), 7.59–7.66 (m, 1H, ArH), 7.80 (d, J = 6.8 Hz, 0.66H,
ArH), 8.00 (d, J = 8.0 Hz, 0.27H, ArH), 11.75 (s, 0.33H, OH
keto) ppm; 13C NMR (100 MHz, CDCl3): δ = 211.7, 162.7,
162.1, 161.8, 161.6, 159.3, 159.0, 154.4, 154.0, 152.7, 152.6,
141.9, 141.1, 140.7, 132.1, 131.9, 131.5, 123.9, 123.81, 123.77,
123.5, 123.0, 122.7, 116.4, 116.2, 116.0, 115.7, 115.4, 110.7,
110.3, 106.5, 106.2, 106.0, 99.6, 99.5, 99.0, 44.8, 38.1, 35.8,
30.2, 29.7, 29.1, 28.1, 27.8, 27.1 ppm.
1
750 cm−1; H NMR (400 MHz, CD3COCD3): δ = 1.79 (s, 3H,
CH3 ketal), 1.98–2.05 (m, 2H, CH2 ketal), 2.51 (br s, 1H, CH
ketal), 4.66 (br s, 1H, OH ketal), 7.11–7.39 (m, 5H, ArH),
7.57–7.63 (m, 2H, ArH), 7.88 (d, J = 7.2 Hz, 1H, ArH) ppm;
13C NMR (100 MHz, CD3COCD3): δ = 161.9, 161.0, 154.8,
134.4, 133.5, 129.7, 129.6, 125.5, 124.6, 118.0, 105.6, 101.2,
42.4, 39.9, 36.8, 28.9 ppm. HRMS (ESI): m/z calcd for
C19H16BrO4 [M + H]+: 387.02265, found: 387.02342.
(R)-3-[1-(4-Chlorophenyl)-3-oxo-butyl]-4-hydroxychromen-2-one
(5i). Compound 5i was obtained according to the general pro-
cedure as a white solid (67.6 mg, 99% yield); mp 174–176 °C.
The enantiomeric excess was determined by HPLC with a
Daicel Chiralcel IA column (n-hexane–2-propanol–EtOAc
50 : 20 : 30; flow rate 0.5 mL min−1; detection at 254 nm): minor
enantiomer tR = 8.2, major enantiomer tR = 12.1 min, 94% ee;
[α]2D5: 2.0 (c 1.0, CH2Cl2), Lit.12d [α]D25 = −8.8 (c 0.274, aceto-
(R)-4-Hydroxy-3-(1-naphthalen-1-yl-3-oxo-butyl)-chromen-2-
one (5l).17 Compound 5l was obtained according to the general
procedure as a white solid (62.0 mg, 86% yield); mp 98–100 °C.
The enantiomeric excess was determined by HPLC with a
Daicel Chiralpak IA column (n-hexane–2-propanol–EtOAc
50 : 20 : 30; flow rate 0.5 mL min−1; detection at 254 nm): minor
enantiomer tR = 8.4, major enantiomer tR = 10.5 min, 96% ee;
1
nitrile, 79% ee). H NMR (400 MHz, CD3COCD3): δ = 1.77 (s,
3H, CH3 ketal), 2.04–2.07 (m, 2H, CH2 ketal), 2.47 (br s, 1H,
CH ketal), 4.14 (s, 1H, OH ketal), 7.30–7.38 (m, 6H, ArH), 7.62
(t, J = 7.6 Hz, 1H, ArH), 7.88 (dd, J = 8.0, 1.2 Hz, 1H, ArH)
ppm; 13C NMR (100 MHz, CD3COCD3): δ = 162.1, 160.8,
154.8, 145.1, 133.5, 132.9, 131.3, 130.9, 130.0, 129.6, 125.5,
124.7, 117.9, 101.2, 44.5, 37.0, 28.9 ppm.
1
[α]2D5: +4.8 (c 1.0, CH2Cl2). H NMR (400 MHz, CDCl3): δ =
1.59 (s, 0.95H, CH3 ketal), 1.61 (s, 1.75H, CH3 ketal), 2.04 (s,
0.41H, CH2 ketal), 2.29 (s, 0.30H, CH3 keto), 2.47–2.60 (m,
0.88H, CH2 ketal), 2.71 (dd, J = 14.4, 2.0 Hz, 0.50H, CH2
ketal), 3.38 (dd, J = 19.2, 2.4 Hz, 0.14H, CH2 keto), 3.54 (s,
0.41H, OH), 3.98 (d, J = 10.8 Hz, 0.22H, CH ketal), 4.07 (dd,
J = 19.2, 10.4 Hz, 0.15H, CH2 keto), 5.00 (d, J = 6.8 Hz, 0.77H,
CH ketal), 5.32 (dd, J = 10.0, 2.4 Hz, 0.11H, CH keto),
7.21–7.95 (m, 10H, ArH), 8.12 (d, J = 8.4 Hz, 1H, ArH), 9.70
(s, 0.12H, OH keto) ppm; 13C NMR (100 MHz, CDCl3): δ =
212.5, 162.2, 161.6, 160.7, 160.2, 159.8, 152.7, 152.5, 139.4,
(R)-4-Hydroxy-3-[1-(4-nitrophenyl)-3-oxo-butyl]-chromen-2-one
(5j).12a Compound 5j was obtained according to the general pro-
cedure as a white solid (69.5 mg, 98% yield); mp 191–193 °C.
The enantiomeric excess was determined by HPLC with a
Daicel Chiralcel IA column (n-hexane–2-propanol–EtOAc
Org. Biomol. Chem.
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