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Paper | Regular issue | Vol 38, No. 4, 1994, pp.779-784
Published online, 1st January, 1970
DOI: 10.3987/COM-93-6609
An Improved Synthesis of 5-Alkyl-2,3-dihydrofuran-2,3-diones

C. Oliver Kappe,* Gert Kollenz, and Curt Wentrup

*Institute for Organic Chemistry, Karl-Franzens-University Graz, Heinrichstrasse. 28, A-8010 Graz, Austria

Abstract

The synthesis of 5-tert-butyl-2,3-dihydrofuran-2,3-dione (2a) from ethenyloxysilane (3) and oxalyl chloride is reinvestigated. Apart from 2a, two other reaction products, namely furan-3-yl oxalate (6) and difuran-3-yl oxalate (6) and difuran-3-yl oxalate (7) are isolated, explaining the low yield of 2a in this process. An improved method for the preparation of 2a, and its 5-methyl analog (2b) by cyclization of acylpyruvic acids (8a,b) is described.