E. Golan et al. / Tetrahedron Letters 45 (2004) 3397–3399
3399
2
. A detailed procedure for the preparation of HOFÆCH
can be found in: Dayan, S.; Bareket, Y.; Rozen, S.
3
CN
crude product was usually purified either by vacuum flash
chromatography, using silica-gel 60H (Merck), or recrys-
tallization.
Tetrahedron 1999, 55, 3657–3664.
. Rozen, S.; Carmeli, M. J. Am. Chem. Soc. 2003, 125,
1
13
3
11. H NMR and C NMR spectra were obtained at 200 and
50.2 MHz, respectively, with CDCl as solvent and Me Si
as an internal standard. IR spectra were recorded in
CHCl solution on a FTIR spectrophotometer. The
8
118–8119.
. (a) Dayan, S.; Kol, M.; Rozen, S. Synthesis 1999, 1427–
3
4
4
1
1
430; (b) Rozen, S.; Dayan, S. Angew. Chem., Int. Ed.
999, 38, 3471–3473.
3
spectral properties of all known products are in excellent
agreement with their structures, and are consistent with
those described in the literature.
5
6
. Dayan, S.; Ben-David, I.; Rozen, S. J. Org. Chem. 2000,
5, 8816–8818.
. (a) Rozen, S.; Kol, M. J. Org. Chem. 1990, 55, 5155–5159;
b) Rozen, S.; Bareket, Y.; Dayan, S. Tetrahedron Lett.
996, 37, 531–534; (c) Rozen, S.; Bareket, Y.; Blum, J.
6
12. Murray, R. W.; Singh, M.; Rath, N. P. Tetrahedron 1999,
55, 4539–4558.
13. Alder, K.; Flock, F. H.; Beumling, H. Chem. Ber. 1960,
93, 1896–1899.
(
1
Tetrahedron Lett. 1997, 38, 2333–2334.
7
8
9
. Rozen, S.; Golan, E. Eur. J. Org. Chem. 2003, 1915–1917.
. Rozen, S. Acc. Chem. Res. 1996, 29, 243–248.
. Ruecker, C.; Seppelt, W.; Fritz, H.; Prinzbach, H. Chem.
Ber. 1984, 117, 1801–1833.
14. Basselier, J. J.; Le Roux, J. P. Bull. Soc. Chim. Fr. 1971,
12, 4448–4454.
ꢀ
1
15. Compound 11: mp 164 °C (from MeOH). IR cm : 1745.
H NMR 3.73 (6H, s), 3.68 (6H, s), 3.55–3.54(2H, m),
1
1
3
1
0. General procedure for working with fluorine: Fluorine is a
strong oxidant and a very corrosive material. It should be
used only with an appropriate vacuum line such as the one
described in Refs. 2 and 4a. For the occasional user,
3.12–3.11 (2H, m), 3.09 ppm (2H, s). C NMR 172.2,
171.4, 52.1, 52.0, 49.9, 43.7, 43.0, 33.5 ppm. HRMS (CI)
þ
ðm=zÞ: (MH) calcd for C16
H
20
O
9
, 357.1186; found,
: C, 53.93; H, 5.66.
357.1185. Anal. Calcd for C16
Found: C, 54.29; H, 5.61.
H
20
O
9
2
however, various premixed mixtures of F in inert gases are
1
commercially available, simplifying the process. If elemen-
tary precautions are taken, work with fluorine is relatively
simple and we have had no bad experiences working with it.
16. Compound 14: mp 124 °C (from CHCl
(CD
3
). H NMR
CN) 3.14(1H, d, J ¼ 17 Hz), 3.05 (1H, d, J ¼ 6 Hz),
3
1
3
2.90 (1H, d, J ¼ 6 Hz), 2.55 ppm (1H, d, J ¼ 17 Hz).
C
NMR 171.5, 171.4, 54.2, 52.1, 37.4 ppm. HRMS (CI)
General procedure for producing HOFÆCH
Mixtures of 10–15% F with nitrogen were used in this
work. They were passed at a rate of about 400 mL per
minute through a cold ()10 °C) mixture of CH CN (60 mL)
and H O (6 mL). The development of the oxidizing power
3
CN complex:
þ
2
ðm=zÞ: (MH) calcd for
C
129.0189. Anal. Calcd for C
5
H
5
O
4
,
129.0188; found,
.monohydrate: C,
5
H
5
O
41.10; H, 4.14. Found: C, 40.57; H, 4.19.
4
3
2
17. Rozen, S.; Bareket, Y. Chem. Commun. 1996, 627–628.
18. Moriarty, R. M.; Prakash, O.; Musallam, H. A.
J. Heterocycl. Chem. 1985, 22, 583–584.
was monitored by reacting aliquots with an acidic aqueous
solution of KI. The liberated iodine was then titrated with
thiosulfate. Typical concentrations of the oxidizing reagent
were around 0.4–0.6 mol/L.
19. Epoxide of 3-propylidene-3H-isobenzofuran-1-one 18: mp
1
ꢀ1
56 °C (from n-hexane). IR cm : 1787. H NMR 7.93 (1H,
dd, J ¼ 1 Hz), 7.77–7.59 (2H, m), 7.38 (1H, dd,
¼ 8 Hz, J
General procedure for epoxidations: The olefin (usually 4–
8
1
2
mmol) was dissolved in CH
2
Cl
2
, usually at 0 °C. The
J
1
¼ 8 Hz, J ¼ 1 Hz), 3.62 (1H, t, J ¼ 6 Hz), 2.11–1.85
2
1
3
HOFÆCH CN solution, kept at similar or lower tempera-
3
(2H, m), 1.14ppm (3H, t, J ¼ 8 Hz). C NMR 167.0,
ture, was added in one portion to the reaction mixture and
after seconds or a few minutes the reaction was stopped by
143.3, 134.7, 131.2, 127.7, 125.5, 121.4, 89.6, 64.8, 21.8,
10.0 ppm. HRMS (CI) ðm=zÞ: (MH)+ calcd for C11
11 3
H O ,
H O : C,
10 3
adding NaHCO
3
. The organic material was extracted with
. The
191.0708; found, 191.0714. Anal. Calcd for C11
69.46; H, 5.30. Found: C, 69.57; H, 5.40.
CH Cl , washed with water and dried over MgSO
2
2
4