1
610
S. K. Das et al.
LETTER
(
14) Takhi, M.; Abdel-Rahman, A. A.-H.; Schmidt, R. R. Synlett
001, 427.
15) Das, S. K.; Reddy, K. A.; Abbineni, C.; Roy, J.; Rao, K. V.
1 H, H-5), 3.98 (t, 1 H, J = 7.1 Hz, OCH ), 4.95 (br s, 1H, H-
2
2
1), 5.03 (dd, 1 H, J = 9.3 Hz, 1.5 Hz, H-4), 5.77 (dd, 1 H,
J = 10.3 Hz, 1.9 Hz, H-2), 5.84 (dd, 1 H, J = 10.3 Hz, 1.9 Hz,
H-3), 7.20–7.32 (m, 5 H, Ph). IR (Neat): 1745, 1374, 1237,
(
L. N.; Sachwani, R. H.; Iqbal, J. Tetrahedron Lett. 2003, 44,
–
1
+
4507.
1107, 1039, 918 cm . LC-MS (CI): m/z 277 (M + 1).
(6S,2R,3R)-2-Methylcarbonyloxymethyl-6-(2-propyn-
(
16) A Typical Procedure: To a solution of glycal (50 mg) and
1
alcohol (2 equiv) in acetonitrile (1 mL) InCl (30 mol%) was
yloxy)-3,6-dihydro-2H-3-pyranyl acetate: H NMR
3
added and the mixture irradiated with microwaves (LG
model: MC-804AAR) for the appropriate time (see Table 1).
The reaction mixture was then diluted with ethyl acetate and
washed with water, dried (Na SO ) and evaporated to
dryness. The residue was purified on silica gel (100–200
mesh) to afford the desired 2,3-unsaturated products as
summarized in Table 1.
(CDCl , 400 MHz): d 2.076, 2.084 (2 s, 6 H, 2Ac), 2.93 (t, 1
3
H, J = 2.4 Hz, acetylene H), 4.22–4.32 (m, 5 H, H-5, H-6,
OCH ), 5.04 (dd, 1 H, J = 5.4 Hz, 2.4 Hz, H-4), 5.29 (d, 1 H,
2
J = 2.9 Hz, H-1), 6.04 (dd, 1 H, J = 10.3 Hz, 2.9 Hz, H-2),
6.15 (ddd, 1 H, J = 10.0 Hz, 5.4 Hz, 1.0 Hz, H-3). IR (Neat):
2
4
–
1
1743, 1590, 1372, 1234, 1102, 1039, 757 cm .
+
LC-MS (CI): m/z 269 (M + 1).
(
17) (a) Moufid, N.; Chapleur, Y.; Mayon, P. J. Chem. Soc.,
Perkin Trans. 1 1992, 999. (b) Swamy, N. R.;
(6S,2R,3R)-2-Methylcarbonyloxymethyl-6-(4-pentenyl-
1
oxy)-3,6-dihydro-2H-3-pyranyl acetate: H NMR (CDCl ,
3
Venkateswarlu, Y. Synthesis 2002, 598. (c) Konstantinović,
S.; Predojević, J.; Gojković, S.; Ratković, Z.; Mojsilović, B.;
Pavlović, V. Indian J. Chem., Sect. B 2001, 40, 1242.
400 MHz): d 2.08, 2.09 (2 s, 6 H, 2Ac), 1.66–1.78 (m, 2 H,
OCH CH CH -), 2.10–2.20 (m, 2 H, OCH CH CH -), 3.50–
2
2
2
2
2
2
3.59 (m, 1 H, OCH CH CH -), 3.75–3.84 (m, 1 H,
2
2
2
(
d) Dearg, S. B.; Steven, V. L.; Sadie, V.; Mervyn, T.
OCH CH CH -), 4.20–4.09 (m, 2 H, H-6), 4.33–4.40 (m, 1
2 2 2
Tetrahedron 1991, 47, 1329. (e) Konstantinović, S.;
Predojević, J.; Gojković, S.; Ratković, Z.; Dimitrijević, B.;
Mojsilović, B. Indian J. Chem., Sect. B 2001, 40, 802.
H, H-5), 4.95–5.04 (m, 3 H, H-4 and CH=CH ), 5.06 (d, 1 H,
2
J = 2.0 Hz, H-1), 5.77–5.87 (m, 1 H, CH=CH ) 6.03 (dd, 1
2
,
H, J = 10.2 Hz, 2.9 Hz, H-2), 6.15 (ddd, 1 H, J = 10.0 Hz, 5.4
(
f) Shanmugasundaram, B.; Bose, A. K.; Balasubramanian,
Hz, 1.0 Hz, H-3). IR (Neat): 1744, 1372, 1232, 1106, 1049,
–
1
+
K. K. Tetrahedron Lett. 2002, 43, 6795. (g) Kelly, D. R.;
Picton, M. R. J. Chem. Soc., Perkin Trans. 1 2000, 1571.
912 cm . LC-MS (CI): m/z 299 (M + 1).
(3R,6R)-3-Allyloxy-3,6-dihydro-2H-3-pyranyl acetate
1
(
h) Halcomb, R. L.; Boyer, S. H.; Wittman, M. D.; Olson, S.
(major isomer): H NMR (CDCl , 400 MHz): d 2.09 (s, 3
3
H.; Denhart, D. J.; Liu, K. K. C.; Danishefsky, S. J. J. Am.
Chem. Soc. 1995, 117, 5720. (i) Marco-Contelles, J.; Ruiz,
J. Tetrahedron Lett. 1998, 39, 6393. (j) Naz, N.; Al-Tel, T.
H.; Al-Abed, Y.; Voelter, W. J. Org. Chem. 1996, 61, 3250.
18) All new compounds were fully characterized. Spectral and
analytical data were in good agreement. Spectral data of
H, Ac), 3.80–3.87 (m, 1 H, OCH CH=CH ), 4.07 (dd, 1 H,
2
2
J = 7.8 Hz, 1.5 Hz, H-5a), 4.09–4.20 (m, 1 H,
OCH CH=CH ), 4.24 (dd, 1 H, J = 6.4 Hz, 1.5 Hz, H-5b),
2
2
4.94–4.97 (m, 1 H, H-4), 5.05 (d, 1 H, J = 2.4 Hz, H-1), 5.18–
5.33 (m, 2 H, OCH CH=CH ), 5.83–5.98 (m, 1 H,
(
2
2
OCH CH=CH ), 6.04 (dd, 1 H, J = 10.0 Hz, 3.0 Hz, H-2),
2
2
(
2S,3R,6R)-2-methyl-6-phenethyloxy-3,6-dihydro-2H-3-
6.09 (dd, 1 H, J = 10.2 Hz, 4.9 Hz, H-3). IR (Neat): 1738,
1
–1
pyranyl acetate: H NMR (CDCl , 400 MHz): d 1.16 (d, 3
H, J = 6.4 Hz, H-6), 2.08 (s, 3 H, Ac), 2.93 (t, 2 H, J = 7.1
Hz, PhCH ), 3.76 (t, 1 H, J = 7.1 Hz, OCH ), 3.83–3.90 (m,
1373, 1238, 1102, 1042, 959 cm . LC-MS (CI): m/z 199
3
+
(M + 1).
2
2
Synlett 2003, No. 11, 1607–1610 © Thieme Stuttgart · New York