Collect. Czech. Chem. Commun. 1999, 64, 1154-1158

3-Bromo-2,5-dihydrofuran-2-one and 4-Bromo-2,5-dihydrofuran-2-one

Lothar Breckera,*, Wolfgang Kreisera,*, Ludger Ernstb and Henning Hopfb

a Naturstoffchemie, Universität Dortmund, D-44221 Dortmund, Germany
b Institut für Organische Chemie, Technische Universität Braunschweig, Hagenring 30, D-38106 Braunschweig, Germany


Although 3-bromo-2,5-dihydrofuran-2-one and 4-bromo-2,5-dihydrofuran-2-one were first reported in 1894, considerable ambiguity still exists about the correct structure assignment of the two compounds. The present article gives a brief overview on the varying assignments of constitution and describes a novel method for the formation of 3-bromo-2,5-dihydrofuran-2-one. A comparison is made of the experimental 13C NMR chemical shifts with values predicted by increment calculations and experimental 1JC-C coupling constants are given for both compounds. Secure structural assignments are now available for both isomers.

Keywords: Revision; Bromo-2,5-dihydrofuran-2-ones; Butenolides; Structure assignments; NMR spectroscopy; Lactones.