LETTER
Tetrahydrofuranylation of Alcohols
2293
Table 2 Reaction of Ethers with PhI(OAc) and Decanol under Microwave and Thermal Conditions1
0
2
Entry
1
Ether
Product(s)
Yield (%) microwave conditionsa Yield (%) thermal conditionsb
<10
–
O
CHO
5
6
2
3
4
O
O
O
O
10
8
n-C10H21m
O
7
8
10 (17) + 6 (3)
38
O
O
O
CH3
O
9
10
O
O
n-C10H21
O
n-C10H21
m
0,
12 (23), 13 (11)
O
+
O
11 recovered
O
O
H
1
1
4
1
2
13
5
O
OH
OAc
6 (40)c
14 (13), 15 (3), 16 (6), 17 (3),
OAc
OH
+ Polymers
6
+
+
1
4
15
OH
On-C10H21m
1
On-C10H21
OH
+
1
6
17
a
With air cooling (100 W, actual temperature 83–87 °C), for 4 h.
b
c
Thermal conditions: 2.0 mmol each of PhI(OAc) and alcohol, with cyclic ether in a sealed microwave tube at 75–90 °C, for 24 h.
2
When CH Cl was used as a co-solvent, under microwave conditions, a 2:1 mixture of 14 and 15 was isolated in 88% yield.
2
2
Table 2. Reaction of decanol and PhI(OAc) with diethyl and THF as both solvent and reagent. Significant rate en-
2
ether gave only oxidation of decanol, and no acetal prod- hancements can be seen, in some cases, when the reac-
uct. Reaction of 1,4-dioxane under microwave conditions tions are carried out in a microwave reactor.
gave only 10% of the desired acetal (Table 2, entry 2),
while thermal reaction conditions gave only 8%. Reaction
of tetrahydropyran under identical reaction conditions
Acknowledgment
(
microwave and thermal) gave 17% and 38%, respective- We thank the Royal Society for providing a Royal Society USA
Fellowship for ANF during his sabbatical year (2003-2004). We
ly, of the tetrahydropyranyl acetate 10 along with a small
amount (3%) of decanal (Table 2, entry 3). Of equal inter-
est was the reaction of 1,3-dioxolane under these reaction
conditions. It was hoped that oxidation of the formyl me-
thylene and reaction with the alcohol would access the
orthoester. While microwave reaction gave only starting
material, the thermal reaction gave two major products;
the desired orthoester 12 and formyl decanoate 13
acknowledge the Royal Society, The National Science Foundation
INT-0209956), and the Donors of the American Chemical Society
Petroleum Research Fund, for funding this collaboration as well as
support by the EPSRC (GR/S 25456 and GR/S 73105).
(
References
(
1) (a) Wirth, T.; Hirt, U. H. Synthesis 1999, 1271. (b) Hirt, U.
H.; Schuster, M. F. H.; French, A. N.; Wiest, O. G.; Wirth,
T. Eur. J. Org. Chem. 2001, 1569. (c) Wirth, T. Top. Curr.
Chem. 2003, 224. (d) Boye, A. C.; Meyer, D.; Ingison, C.
K.; French, A. N.; Wirth, T. Org. Lett. 2003, 5, 2157.
(
Table 2, entry 4) in low yields.
Finally, reaction of styrene oxide under microwave condi-
tions (Table 2, entry 5) gave large quantities of unreacted
PhI(OAc) and oxidation of decanol. The corresponding
2
(2) (a) Greene, T. W.; Wuts, P. G. M. Protective Groups in
Organic Chemistry; Wiley: New York, 1999, Chap. 2, 57–
58. (b) Sosnovsky, G. J. Org. Chem. 1960, 25, 874.
thermal reaction gave a mixture of six compounds, 14–17,
resulting from epoxide opening by either acetate or de-
canol, in low yield and two others that appear to be poly-
meric in nature. For solubility reasons, and for
comparison, we performed the microwave reaction with
dichloromethane as a co-solvent, and we obtained an 88%
yield of the acetylated alcohols, 14 and 15, as a 2:1 mix-
ture.
(c) Sosnovsky, G. Tetrahedron 1961, 13, 241. (d) Eliel, E.
L.; Nowak, B. E.; Daignault, R. A.; Badding, V. G. J. Org.
Chem. 1965, 30, 2441. (e) Kruse, C. G.; Broekhof, N. L. J.
M.; van der Gen, A. Tetrahedron Lett. 1976, 20, 1725.
(
f) Kruse, C. G.; Poels, E. K.; Jonkers, F. L.; van der Gen, A.
J. Org. Chem. 1978, 43, 3548. (g) Maione, A. M.; Romeo,
A. Synthesis 1987, 250. (h) Jung, J. C.; Choi, H. C.; Kim, Y.
H. Tetrahedron Lett. 1993, 34, 3581. (i) Yu, B.; Hui, Y.
Synth. Commun. 1995, 25, 2037. (j) Hon, Y. S.; Lee, C. F.
Tetrahedron Lett. 1999, 40, 2389. (k) Baati, R.; Valleix, A.;
In summary, we have revealed a new procedure for the tet-
rahydrofuranylation of simple alcohols using PhI(OAc)2,
Synlett 2004, No. 13, 2291–2294 © Thieme Stuttgart · New York