was added TMSOTf (5 µL, 0.028 mmol). After stirring at the
same temperature for 5 min the reaction mixture was quenched
by the addition of phosphate buffer (pH 7.4, 2 mL), the aque-
ous layer extracted with diethyl ether (3 × 5 mL), and the com-
(1H, dd, J 15.0 and 8.2, CHCHHCOCH ), 2.43 (2H, t, J 7.3,
2
CHCH COCH ), 2.37 (1H, dd, J 15.0 and 7.4, CHCHH-
2
2
COCH ), 1.74–1.18 (20H, m, 10 × CH ), 0.88 (3H, t, J 7.4,
2
2
CH ), 0.86 (3H, t, J 6.4, CH ); δ (100 MHz; CDCl ): 209.6
3
3
C
3
bined organic extracts dried (MgSO ), filtered and evaporated
(CH COCH ), 71.6 (CHOCHCH COCH ), 67.6 (CHOCH-
4
2 2 2 2
in vacuo to give a slightly yellow oil. Proton NMR spectroscopy
of the crude product showed a 2:98 ratio of 19:16 by integra-
CH COCH ), 47.3 (CHCH COCH ), 43.2 (CHCH COCH ),
2 2 2 2 2 2
32.9 (CH ), 31.8 (CH ), 30.3 (CH ), 29.3 (CH ), 25.7 (CH ),
2
2
2
2
2
tion of the signals at δ = 3.02 (16) and 2.92 (19). Purification
25.6 (2 × CH ), 22.6 (CH ), 22.3 (CH ), 16.5 (CH ), 14.0 (CH ),
2 2 2 2 3
ϩ
H
by flash column chromatography, eluting with 20% diethyl
ether–petroleum ether (bp 40–60 ЊC), gave 19 (3 mg, 2%) and
then 16 (120 mg, 80%) as colourless oils.
13.8 (CH ); m/z (FAB) 269 (23%, MH ), 169 (35%), 85 (100%).
3
ϩ
Found (FAB): MH 269.2481. C H O requires 269.2480.
17
33
2
Data for 20 (Found: C, 76.14; H, 12.03%. C H O requires:
17
32
2
Ϫ1
Data for 16 (Found: C, 79.10; H, 9.84%. C H O requires:
C, 76.08; H, 12.02%); νmax (thin film)/cm 2931, 2856, 1712,
19
28
2
Ϫ1
C, 79.12; H, 9.78%); νmax (thin film)/cm 2929, 2856, 1687,
598, 1448, 1376, 1042; δH (400 MHz; CDCl ) 7.96–7.94 (2H,
1456, 1370, 1274, 1055; δH (400 MHz; CDCl ): 3.76–3.70 (1H,
3
1
m, OCHCH CO), 3.27–3.22 (1H, m, CHOCHCH CO), 2.64
3
2
2
m, o-Ph), 7.54 (1H, t, J 7.3, p-Ph), 7.45 (2H, t, J 7.3, m-Ph),
.39–4.33 (1H, m, CHCH COPh), 3.74–3.69 (1H, m,
(1H, dd, J 15.0 and 8.0, CHCHHCOCH ), 2.52–2.33 (3H, m,
2
4
CHCH COCH2 and CHCHHCOCH ), 1.82–1.08 (20H, m,
2
2
2
CHOCHCH COPh), 3.30 (1H, dd, J 15.4 and 8.7, CHH-
10 × CH ), 0.89 (3H, t, J 7.3, CH ), 0.87 (3H, t, J 6.9, CH );
2
2
3
3
COPh), 3.02 (1H, dd, J 15.4 and 6.6, CHHCOPh), 1.80–1.61
δC (100 MHz; CDCl ): 210.1 (CH COCH ), 78.0 (CHOCH-
3 2 2
(
5H, m, CHH and 2 × CH ), 1.45–1.16 (11H, m, CHH and
CH COCH ), 74.6 (CHOCHCH COCH ), 49.5 (CHCH2-
2
2 2 2 2
5
× CH ), 0.86 (3H, t, J 6.6, CH ); δ (100 MHz; CDCl ): 198.7
COCH ), 43.7 (CHCH COCH ), 36.5 (CH ), 31.8 (CH ), 31.7
2 2 2 2 2
2
3
C
3
(
7
(
COPh), 137.4 (Ph, quat.), 132.9 (Ph), 128.5 (Ph), 128.2 (Ph),
2.0 (OCHCH COPh), 67.7 (CHOCHCH COPh), 43.4
(CH ), 29.3 (2 × CH ), 25.6 (CH ), 25.5 (CH ), 22.6 (2 × CH ),
2 2 2 2 2
22.3 (CH ), 14.0 (CH ), 13.8 (CH ); m/z (FAB) 269 (100%,
2 3 3
ϩ ϩ
2
2
CH COPh), 32.8 (CH ), 31.8 (CH ), 30.4 (CH ), 29.6 (CH ),
MH ). Found (FAB): MH 269.2481. C H O requires
17 33 2
2
2
2
2
2
2
9.2 (CH ), 25.7 (CH ), 22.6 (CH ), 18.5 (CH ), 14.1 (CH ); m/z
269.2480.
2
2
2
2
3
ϩ
(
FAB) 289 (20%), 169 (21%), 105 (100%). Found (FAB): MH
89.2161. C H O requires 289.2168.
2
19
29
2
Isomerisation to the equilibrium mixture at ambient temper-
ature. Following the procedure described above for isomeris-
ation of 15 to the equilibrium mixture at ambient temperature,
17 (0.071 g, 0.27 mmol) was isomerised to a mixture of 20 and
Data for 19 (Found: C, 79.16; H, 9.79%. C H O requires:
19
28
2
Ϫ1
C, 79.12; H, 9.78%); νmax (thin film)/cm 2929, 2861, 1688,
597, 1444, 1348, 1064; δH (400 MHz; CDCl ) 7.98–7.96 (2H,
1
3
m, o-Ph), 7.54 (1H, t, J 7.3, p-Ph), 7.44 (2H, t, J 7.8, m-Ph),
.96–3.89 (1H, m, CHCH COPh), 3.33–3.25 (2H, m, CHO-
1
7 in the ratio 93:7 by integration of the signals at δ = 2.75
H
3
2
(17) and 2.64 (20) in the 400 MHz proton NMR spectrum. The
combined isolated yield of 17 and 20 was 0.068 g, 96%; spectro-
scopic data for 17 and 20 were identical to those previously
described.
CHCH COPh and CHHCOPh), 2.92 (1H, dd, J 15.6 and
2
6
.2, CHHCOPh), 1.85–1.19 (16H, m, 8 × CH ) 0.85 (3H, t,
2
J 6.6, CH ); δ (100 MHz; CDCl ): 198.9 (COPh), 137.6 (quat.,
3
C
3
Ph), 132.9 (Ph), 128.4 (Ph), 128.3 (Ph), 78.1 (OCHCH COPh),
2
7
4.6 (CHOCHCH COPh), 45.6 (CH COPh), 36.5 (CH ), 31.8
2
2
2
1
5
-(cis-5-Heptyltetrahydrofuran-2-yl)propan-2-one and 1-(trans-
-heptyltetrahydrofuran-2-yl)propan-2-one 21
(
(
(
CH ), 31.7 (CH ), 29.3 (2 × CH ), 25.4 (CH ), 23.6 (CH ), 22.6
CH ), 14.1 (CH ); m/z (FAB) 289 (87%), 105 (100%). Found
FAB): MH 289.2163. C H O requires 289.2168.
2 2 2 2 2
2
3
ϩ
To a stirred solution of 13 (0.184 g, 0.81 mmol) in dichloro-
methane (2.7 mL) at Ϫ78 ЊC was added TMSOTf (0.007 mL,
19
29
2
0
.04 mmol). After stirring at Ϫ78 ЊC for 5 min the reaction
mixture was quenched by the addition of phosphate buffer (pH
.4, 3 mL), the aqueous layer extracted with diethyl ether
3 × 10 mL), and the combined organic extracts dried (MgSO ),
Isomerisation to the equilibrium mixture at ambient temper-
ature. Following the procedure described above for isomeris-
ation of 15 to the equilibrium mixture at ambient temperature,
7
(
1
1
(
6 (50 mg, 0.174 mmol) was isomerised to a mixture of 19 and
4
filtered and evaporated in vacuo to give a slightly yellow oil.
Proton NMR spectroscopic analysis of the crude product
showed two products in the ratio of 45:55 by integration of the
6 in the ratio 93.5:6.5 by integration of the signals at δ = 3.02
H
16) and 2.92 (19) in the 400 MHz proton NMR spectrum. The
combined isolated yield of 16 and 19 was 49 mg, 98%; spectro-
scopic data for 16 and 19 were identical to those previously
described.
signals at δ = 2.64 (minor isomer) and 2.75 (major isomer).
H
Purification by flash column chromatography, eluting with 20%
diethyl ether–petroleum ether (bp 40–60 ЊC), gave an insepar-
able mixture of cis- and trans-21 (0.166 g, 90%) as a colourless
oil. Data for mixture of isomers (Found: C, 73.62; H, 11.61%.
C H O requires: C, 74.29; H, 11.58%); ν (thin film)/cm
1
1
-(trans-6Ј-Hexyltetrahydropyran-2Ј-yl)hexan-2-one 17 and
-(cis-6Ј-hexyltetrahydropyran-2Ј-yl)hexan-2-one 20
Ϫ1
14
26
2
max
Formation under kinetic control. To a stirred solution of 6
200 mg, 0.75 mmol) in dichloromethane (2.5 mL) at Ϫ78 ЊC
2927, 2857, 1714, 1463, 1358, 1165, 1072; δH (400 MHz;
CDCl ): 4.32–4.25 (1H minor, m, OCHCH CO), 4.17–4.13 (1H
(
3
2
was added TMSOTf (5 µL, 0.040 mmol). After stirring at the
same temperature for 5 min the reaction mixture was quenched
by the addition of phosphate buffer (pH 7.4, 3 mL), the aque-
ous layer extracted with diethyl ether (3 × 5 mL), and the com-
major, m, OCHCH CO), 3.93–3.85 (1H minor, m, CHOCH-
2
CH CO), 3.78–3.74 (1H major, m, CHOCHCH CO), 2.74–2.67
2
2
(1H major and 1H minor, m, CHHCOCH ), 2.53–2.45 (1H
3
major and 1H minor, m, CHHCOCH ), 2.14 (3H major and 3H
3
bined organic extracts dried (MgSO ), filtered and evaporated
minor, s, COCH ), 2.11–1.15 (16H major and 16H minor, m,
4
3
in vacuo to give a slightly yellow oil. Proton NMR spectroscopic
analysis of the crude product showed a 2.5:97.5 ratio of 20:17
8 × CH ), 0.84 (3H major and 3H minor, t, J 6.4, CH CH );
2
2
3
δ (100 MHz; CDCl ): 207.4 (COCH , minor), 207.3 (COCH ,
C
3
3
3
by integration of the signals at δ = 2.75 (17) and 2.64 (20).
major), 79.6 (OCHCH CO, major), 79.0 (OCHCH CO, minor),
H
2
2
Purification by flash column chromatography, eluting with 20%
diethyl ether–petroleum ether (bp 40–60 ЊC), gave 20 (4 mg, 2%)
and 17 (170 mg, 85%) as colourless oils.
76.7 (CHOCHCH CO, major), 74.9 (CHOCHCH CO, minor),
2 2
50.1 (CH CO, major), 49.9 (CH CO, minor), 36.6 (CH , major
2
2
2
and minor), 35.9 (CH , major and minor), 31.8 (CH , major
2
2
Data for 17 (Found: C, 76.18; H, 12.16%. C H O requires:
and minor), 31.2 (CH , major and minor), 30.6 (COCH ,
17
32
2
2
3
Ϫ1
C, 76.08; H, 12.02%); νmax (thin film)/cm 2934, 2860, 1714,
461, 1378, 1203, 1033; δH (400 MHz; CDCl ): 4.41–4.15 (1H,
major and minor), 29.6 (CH , major and minor), 29.2
2
1
(CH , major and minor), 26.1 (CH , major and minor), 22.6
3
2
2
m, OCHCH CO), 3.67–3.61 (1H, m, CHOCHCH CO), 2.74
(CH , major and minor), 14.0 (CH CH , major and minor); m/z
2
2
2
2
3
2
392
J. Chem. Soc., Perkin Trans. 1, 2000, 2385–2394