Preparation of these reagents was achieved by iodine(III)-
promoted ligand transfer and hence oxidation of polystyrene-
bound halides 1a,b.7 As a result of this transformation we
presumably prepared polymer-bound di(acyloxy)halogen-
ate(I) anions 3a-c (Scheme 1).5,8 Thus, reaction of bromide
Table 1. Haloacetoxylation of Alkenes
Scheme 1
1a with (diacetoxyiodo)benzene 2a afforded polymer 3a
while electrophilic reagents 3b and 3c were generated from
polymer-bound iodide 1b after treatment with 2a and 2b,
respectively. We found that extensive washing of the
resulting polymers does not result in their deactivation, which
clearly supports the ionic character of the active species on
the polymer. For resin 3b, the weight increase served as an
indicator for efficient ligand transfer onto polymer-bound
halide and gave most reproducible results (about 90%
conversion with respect to theoretical iodide).7 Furthermore,
both reagents can be stored below 0 °C for weeks without
loss of activity.
These electrophilic reagents promote 1,2-haloacetoxylation
of various alkenes under very mild conditions with high
efficiency (Table 1). Unlike classical reagents that have been
employed for the haloacetoxylation of olefinic double bonds,
immobilized reagents 3a and 3b do not require glacial acetic
acid9 or heavy metals.10 1,2-Functionalization of alkenes
4-12 using reagent 3b typically afforded a single cohalo-
gention product. The addititon proceeded with trans selectiv-
ity as demonstrated for cyclohexene 4, indene 5, and styrenes
7-10.11,12 Halogenated substrates 6 and 9 reacted very
(7) General Procedure for the Preparation of Polymer-Bound
Reagents 3a-c: A suspension of polymer bound halide (available from
Fluka; 3.2 g/mmol for bromide; 2.9 mmol/g for iodide) and PhI(OAc)2 or
PhI(O2CCF3)2 (1.8 equiv) in dry CH2Cl2 (3 mL/mmol halide anion) under
nitrogen was shaken at 300 rpm for 6 h at room temperature. The brownish
suspension was protected from light. Filtration and washing of the resin
with CH2Cl2 (3×) and drying in vacuo afforded the light yellow reagents
3a and 3b or pink resin 3c.
(8) (a) Doleschall, G.; To´th, G. Tetrahedron 1980, 36, 1649-1665. (b)
Sza´ntay, C.; Blasko´, G.; Ba´rcrczai-Beke, M.; Pe´chy, P.; Do¨rnei, G.
Tetrahedron Lett. 1980, 21, 3509-3512. (c) Matsuo, K.; Ishida, S.; Takuno,
Y. Chem. Pharm. Bull. 1994, 42, 1149-1150.
a For experimental details, refer to ref 11. b All yields refer to isolated
pure products. Values in parentheses refer to yields/purities of the crude
products. The differences relative to the isolated yields are due in part to
decomposition during the course of chromatographic purification. c Reaction
temperature, 80 °C. d Additionally, 23 (26%) and 24 (8%) were isolated.
e Very labile 1,2-addition products. f Additionally, 25 (77%) was isolated.
(9) (a) Mangoni, L.; Adinolfi, M.; Barone, G.; Parrilli, M. Tetrahedron
Lett. 1973, 4485-4486. (b) Mangoni, L.; Adinolfi, M.; Barone, G.; Parrilli,
M. Gazz. Chim. Ital. 1975, 105, 377-383. (c) Adinolfi, M.; Parrilli, M.;
Barone, G.; Laonigro, G.; Mangoni, L. Tetrahedron Lett. 1976, 3661-
3663.
(10) (a) Birckenbach, L.; Goubeau, J.; Berninger, E. Ber. 1932, 65, 1339-
1344. (b) Woodward, R. B.; Brutcher, F. V., Jr. J. Am. Chem. Soc. 1958,
80, 209-211. (c) Cambie, R. C.; Gash, D. M.; Rutledge, P. S.; Woodgate,
P. D. J. Chem. Soc., Perkin Trans. 1 1977, 1157-1162. (d) Barluenga, J.;
Rodriguez, M. A.; Campos, P. J.; Asenio, G. J. Chem. Soc., Chem. Commun.
1987, 1491-1492. (e) Georgoulis, C.; Valery, J. Bull. Soc. Chim. Fr. 1975,
1431-1432. (f) Trainor, R. W.; Deacon, G. B.; Jackson, W. R.; Giunta, N.
Aust. J. Chem. 1992, 45, 1265-1280. (g) Bedekar, A. V.; Nair, K. B.;
Soman, R. Synth. Commun. 1994, 24, 2299-2305.
sluggishly at room temperature; at 80 °C, complete con-
sumption of alkenes was achieved. Under these conditions,
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Org. Lett., Vol. 1, No. 13, 1999