T. Hattori et al. / Tetrahedron 58 +2002) 5215±5223
5221
79.5, 37.8, 30.0, 17.7 and 13.7;IR *neat) 1740 cm 21. Found:
C, 68.17;H, 8.74%. Calcd for C 8H12O2: C, 68.54;H, 8.63%.
3.2.16. 6-sec-Butyl-3,6-dihydro-5-methyl-2H-pyran-2-
one ꢀ3o). Hexane±ethyl acetate *1:1) as the eluent; H
1
NMR *500 MHz) d 5.54±5.53 *1H, m, CHv), 4.83, 4.71
*1H: d, J2.0 Hz, OCH *minor);d, J2.7 Hz, OCH
*major)), 3.02±2.99 *2H, m, CH2CvO), 1.83±1.75 *1H,
m, EtCH), 1.74, 1.72 *3H: d, J1.9 Hz, CH3Cv *major);
d, J1.8 Hz, CH3Cv *minor)), 1.65±1.48, 1.41±1.04 *2H:
m, MeCH2 *minor);m, MeC H2 *major));1.11, 0.82 *3H: d,
J6.9 Hz, MeCH *major);d, J6.9 Hz, MeCH *minor)) and
0.97, 0.91 *3H: t, J7.4 Hz, MeCH2 *minor);t, J7.4 Hz,
MeCH2 *major)); 13C NMR *100 MHz) d 169.6, 131.9
*minor), 131.8 *major), 117.3 *minor), 117.0 *major), 88.1
*minor), 85.8 *major), 38.6 *minor), 38.4 *major), 30.1
*minor), 29.9 *major), 26.1 *minor), 21.9 *major), 19.4
*major), 19.0 *minor), 15.9 *major), 12.1 *minor) and
12.0;IR *neat) 1740 cm 21. Found: C, 71.01;H, 9.57%.
Calcd for C10H16O2: C, 71.39;H, 9.59%.
3.2.9. 3,6-Dihydro-6-pentyl-2H-pyran-2-one ꢀ3h).23
Hexane±ethyl acetate *1:1) as the eluent; 1H NMR
*400 MHz) d 5.88±5.81 *2H, m, CHv£2), 5.00±4.95
*1H, m, OCH), 3.11±3.04 *2H, m, CH2CvO), 1.78±1.72
*2H, m, BuCH2), 1.33±1.30 *6H, m, CH2£3) and 0.91±0.88
*3H, m, Me); 13C NMR *100 MHz) d 169.2, 126.7, 121.5,
79.8, 33.7, 31.5, 30.0, 24.0, 22.5 and 14.0;IR *neat)
1740 cm21
.
3.2.10. 3,6-Dihydro-6,6-dimethyl-2H-pyran-2-one ꢀ3i).24
Hexane±ethyl acetate *2:1) as the eluent; 1H NMR
*500 MHz) d 5.84 *1H, dt, J10.0 and 1.9 Hz, CHv),
5.74 *1H, dt, J10.0 and 3.5 Hz, CHv), 3.04 *2H, dd,
J3.5 and 1.9 Hz, CH2) and 1.48 *6H, s, Me£2); 13C
NMR *125 MHz) d 169.1, 131.9, 119.2, 82.9, 29.0 and
21
28.9;IR *neat) 1736 cm
.
The 1H NMR signals of the minor diastereomer agreed well
with those of the [6R,*S)]-isomer reported in the literature.9e
Thus, the relative con®guration of the major diastereomer
was determined to be 6RS,*RS).
3.2.11. 5-Ethyl-3,6-dihydro-6-propyl-2H-pyran-2-one ꢀ3j).
Hexane±ethyl acetate *3:1) as the eluent; 1H NMR
*400 MHz) d 5.43±5.41 *1H, m, CHv), 4.74±4.71 *1H,
m, OCH), 2.98±2.96 *2H, m, CH2CvO), 2.00±1.94 *2H,
m, CH2), 1.71±1.65 *2H, m, CH2), 1.57±1.35 *2H, m, CH2),
1.46 *3H, t, J7.4 Hz, Me) and 1.01 *3H, t, J7.3 Hz, Me);
3.2.17. 3,6-Dihydro-6-ꢀ1-phenylethyl)-2H-pyran-2-one
ꢀ3p). Hexane±ethyl acetate *2:1) as the eluent; H NMR
1
*500 MHz) d 7.30±7.20 *5H: m, ArH), 5.77±5.76, 5.72±
5.71 *2H: m, CHv *major);m, CH v *minor)), 5.13±5.11,
5.08±5.05 *1H: m, OCH *minor);m, OCH *major)), 3.18,
3.16 *1H: q, J7.1 Hz, PhCH *minor);q, J7.2 Hz, PhCH
*major)), 2.88±2.82, 2.85±2.79 *1H: m, CH2 *major);m,
CH2 *minor)), 2.48±2.42, 2.39±2.33 *1H: m, CH2 *major);
m, CH2 *minor)) and 1.44, 1.39 *3H: d, J7.1 Hz, Me
*minor);d, J7.2 Hz, Me *major)); 13C NMR *125 MHz)
d 169.0, 140.8 *major), 139.8 *minor), 128.6, 128.4, 127.2,
124.3 *major), 124.1 *minor), 122.9 *major), 122.5 *minor),
83.9 *minor), 83.6 *major), 45.3 *major), 44.4 *minor), 29.9
*major), 29.7 *minor), 16.1 *major) and 15.5 *minor);IR
*neat) 1740 cm21. Found: C, 76.88;H, 7.01%. Calcd for
C13H14O2: C, 77.20;H, 6.98%.
13C NMR *100 MHz) d 170.0, 139.5, 114.1, 82.3, 36.5,
21
30.0, 25.1, 17.7, 13.7 and 11.7;IR *neat) 1736 cm
.
Found: C, 71.12;H, 9.49%. Calcd for C 10H16O2: C, 71.39;
H, 9.59%.
3.2.12. 3,5,6,7,8,8a-Hexahydrochromen-2-one ꢀ3k).
Hexane±ethyl acetate *1:1) as the eluent; 1H NMR
*500 MHz) d 5.38±5.37 *1H, m, CHv), 4.82 *1H, m,
OCH), 3.06 *2H, m, CH2CvO), 2.41 *1H, m, CH2), 2.32±
2.30 *1H, m, CH2), 2.05±1.99 *1H, m, CH2), 1.90±1.86 *1H,
m, CH2), 1.81±1.78 *1H, m, CH2), 1.51±1.39 *2H, m, CH2)
and 1.30±1.22 *1H, m, CH2); 13C NMR *100 MHz) d 168.4,
135.7, 111.9, 81.0, 35.4, 32.7, 29.3, 26.6 and 24.0;IR *neat)
1740 cm21. Found: C, 70.72;H, 7.95%. Calcd for C 9H12O2:
C, 71.03;H, 7.95%.
3.2.18. 3,6-Dihydro-5-methyl-6-ꢀ1-phenylethyl)-2H-pyran-
2-one ꢀ3q). Hexane±ethyl acetate *2:1) as the eluent; H
1
3.2.13. 3,6-Dihydro-4-methyl-2H-pyran-2-one ꢀ3l).25
Hexane±ethyl acetate *1:1) as the eluent; 1H NMR
*250 MHz) d 5.61±5.60 *1H, m, CHv), 4.86±4.84 *2H,
m, OCH2), 2.99 *2H, s, CH2CvO) and 1.80 *3H, s, Me);
NMR *500 MHz) d 7.33±7.15 *5H, m, ArH), 5.56±5.54,
5.26±5.25 *1H: m, CHv *major);m, CH v *minor)),
4.85±4.84, 4.82 *1H: m, OCH *major);d, J2.0 Hz, OCH
*minor)), 3.18, 3.17 *1H: qd, J7.3 and 2.0 Hz, PhCH
*minor);qd, J7.2 and 4.2 Hz, PhCH *major)), 2.98±2.91,
13C NMR *62.5 MHz) 169.5, 130.4, 115.9, 68.4, 34.6 and
21
21.1;IR *neat) 1738 cm
.
2.52±2.46 *1H: m, CH2 *major);m, CH *minor)), 2.79±
2
2.72, 1.46±1.40 *1H: m, CH2 *major);m, CH *minor)),
2
3.2.14. 3,6-Dihydro-4,6-dimethyl-2H-pyran-2-one ꢀ3m).26
Hexane±ethyl acetate *3:1) as the eluent; 1H NMR
*500 MHz) d 5.53 *1H, br, CHv), 5.03±5.01 *1H, m,
OCH), 2.95 *2H, s, CH2), 1.78 *3H, s, MeCv) and 1.42
*3H, d, J6.7 Hz, MeCH); 13C NMR *100 MHz) d 169.8,
1.84±1.83, 1.66 *3H: m, MeCv *minor);m, MeCv
*major)) and 1.57, 1.32 *3H: d, J7.3 Hz, MeCH *minor);
d, J7.2 Hz, MeCH *major)); 13C NMR *125 MHz) d 169.8
*minor), 169.6 *major), 142.0 *major), 138.9 *minor), 132.3
*major), 130.9 *minor), 129.1 *minor), 128.5 *major), 128.2
*major), 128.1 *minor), 127.3 *minor), 127.1 *major), 118.3
*major), 118.2 *minor), 87.4 *major), 87.2 *minor), 43.9
*major), 42.4 *minor), 30.1 *major), 29.4 *minor), 19.9
*major), 19.3 *minor), 17.5 *minor) and 14.7 *major);IR
*neat) 1740 cm21. Found: C, 77.45;H, 7.46%. Calcd for
C14H16O2: C, 77.75;H, 7.46%.
130.0, 121.9, 75.8, 34.5, 22.0 and 21.5;IR *neat) 1740 cm 21
.
3.2.15. 3,6-Dihydro-4-methyl-6-phenyl-2H-pyran-2-one
1
ꢀ3n).27 Hexane±ethyl acetate *3:1) as the eluent; H NMR
*500 MHz) d 7.38±7.30 *5H, m, ArH), 5.91 *1H, br, CHv),
5.73±5.71 *1H, m, OCH), 3.06 *2H, s, CH2), 1.85 *3H, s,
Me); 13C NMR *100 MHz) d 169.1, 138.9, 130.6, 128.8,
128.7, 126.8, 120.3, 81.1, 34.7 and 21.6;IR *neat)
3.2.19. 3,6-Dihydro-5-methyl-6-[1-ꢀnaphthalen-1-yl)ethyl]-
2H-pyran-2-one ꢀ3r). Hexane±ethyl acetate *2:1) as the
1740 cm21
.