Download PDF
Synthesis 1995; 1995(10): 1311-1314
DOI: 10.1055/s-1995-4100
paper
© Georg Thieme Verlag, Rüdigerstr. 14, 70469 Stuttgart, Germany. All rights reserved. This journal, including all individual contributions and illustrations published therein, is legally protected by copyright for the duration of the copyright period. Any use, exploitation or commercialization outside the narrow limits set by copyright legislation, without the publisher's consent, is illegal and liable to criminal prosecution. This applies in particular to photostat reproduction, copying, cyclostyling, mimeographing or duplication of any kind, translating, preparation of microfilms, and electronic data processing and storage.

Esters of 2,3-Dihydro-3-oxobenzofuran-2-acetic Acid and 3,4-Dihydro-4-oxo-2H-1-benzopyran-3-acetic Acid by Intramolecular Stetter Reactions

Engelbert Ciganek*
  • *Chemical and Physical Sciences, The DuPont Merck Pharmaceutical Co., Experimental Station Box 80353, Wilmington Delaware 19880-0353, USA
Further Information

Publication History

Publication Date:
31 December 2000 (online)

  PDF Download  Permissions and Reprints All articles of this category

Intramolecular Stetter reaction of methyl 3-(2-formylphenoxy)-prop-2-enoate catalyzed by 3-benzyl-5-(2-hydroxyethyl)-4-methyl-1,3-thiazolium chloride in refluxing dimethylformamide gave methyl 2,3-dihydro-3-oxobenzofuran-2-acetate in 39% yield. The presence of a tertiary amine, which in this case caused destruction of the product, is thus not necessary for the success of the Stetter reaction. When sodium cyanide was used as the catalyst, methyl 2-cyano-2,3-dihydro-4-hydroxy-2H-1-benzopyran-3-carboxylate was formed in 58% yield. Methyl 4-(2-formylphenoxy)but-2-enoate underwent intramolecular Stetter reaction to give methyl 3,4-dihydro-4-oxo-2H-1-benzopyran-3-acetate in 86% yield. Base-catalyzed cyclization of methyl 4-(2-formylphenoxy)but-2-enoate gave methyl-1-benzoxepin-4-carboxylate in 52% yield.

dihydro-3-oxo-2-benzofuranacetates - 3,4-dihydro-4-oxo-2H-benzopyran-3-acetates - intramolecular Stetter reactions