D. Donati et al. / Tetrahedron Letters 46 (2005) 2817–2819
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Acknowledgment
chloride (i) Zander, N.; Gerhardt, J.; Frank, R. Tetrahe-
dron Lett. 2003, 44, 6557; Polymer-supported triphenyl-
phosphine ditriflate: (j) Elson, K. E.; Jenkins, I. D.;
Loughlin, W. A. Tetrahedron Lett. 2004, 45, 2491.
. Kappe, C. O. Angew. Chem., Int. Ed. 2004, 43, 6250.
. (a) Acylation of amines: Sauer, D. R.; Kalvin, D.; Phelan,
K. M. Org. Lett. 2003, 5, 4721; (b) Humphrey, C. E.;
Easson, M. A.; Tierney, J. P.; Turner, N. J. Org. Lett.
2003, 5, 849; (c) Petricci, E.; Botta, M.; Corelli, F.;
Mugnaini, C. Tetrahedron Lett. 2002, 43, 6507; Use of a
polymer-supported Burgess reagent: (d) Brain, C. T.; Paul,
J. M.; Loong, Y.; Oakley, P. J. Tetrahedron Lett. 1999, 40,
3275; Microwave assisted scavengers: (e) Dallinger, D.;
Gorobets, N. Yu.; Kappe, C. O. Org. Lett. 2003, 5,
1205.
The work was financially supported by MIUR (Rome)
as a project within PRIN-2002. Nikem-Research srl
Milan) is also acknowledged for financial support.
4
5
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References and notes
1
. Ley, S. V.; Baxendale, I. R.; Bream, R. N.; Jackson, P. S.;
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2
3
. Janda, K. Bioorg. Med. Chem. Lett. 2002, 12(14).
. For methods where one of the reagents is first linked to a
resin and than esterified during the cleavage (catch and
release) see: supported 1-hydroxybenzotriazole: (a) Pop, I.
E.; Deprez, B. P.; Tartar, A. L. J. Org. Chem. 1997, 62,
8. Crosignani, S.; Gonzales, J.; Swinnen, D. Org. Lett. 2004,
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9. Although dichloromethane is considered an unsuitable
solvent for microwaves, we obtained a reproducible
temperature of 80 °C in the reactor that allowed a rapid
formation of the ester.
2
594; (b) Dendrinos, K. G.; Kalivretenos, A. G. Tetrahe-
dron Lett. 1998, 39, 1321; Triazene based resin (c) Rade-
mann, J.; Smerdka, J.; Jung, G.; Groshe, P.; Schmid, D.
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10. Phenoxyacetic acid benzyl ester. General procedure: the
resin 1 (loading 1.0 mmol/g, 0.2 mmol) and phenoxyacetic
acid 2 (18 mg, 0.12 mmol) are placed in a sealed vial for
microwave-assisted reactions. Dry DCM (1 mL) is added
under nitrogen followed by benzyl alcohol (0.010 mL,
0.1 mmol) and TEA (70 lL, 0.5 mmol). The vial is heated
in microwave cavity (CEM Discover apparatus) at 80 °C
for 2 min (internal pressure 150 psi). The mixture is filtered
through a short pad of dry silica gel that is washed with
2
001, 42, 9179; Polymer-supported O-alkylisoureas: (e)
Crosignani, S.; White, P. D.; Linclau, B. Org. Lett. 2002,
, 1035; (f) Crosignani, S.; White, P. D.; Steinauer, R.;
4
Linclau, B. Org. Lett. 2003, 5, 853; (g) Crosignani, S.;
White, P. D.; Linclau, B. J. Org. Chem. 2004, 69,
5897; One-step Mitsunobu reaction with supported
phosphine: (h) Amos, R. A.; Emblidge, R. W.; Havens, N.
J. Org. Chem. 1983, 48, 3598; Polymer supported sulfonyl
2
Et O. The solvents are evaporated and the product
(23 mg) characterized by NMR and ES-MS analysis or
comparison with an authentic sample.