Base-promoted deacylation of 2-acetyl-2,5-dihydrothiophenes and their oxygen-mediated hydroxylation

• Vladimir G. Ilkin,
• Margarita Likhacheva,
• Igor V. Trushkov,
• Tetyana V. Beryozkina,
• Vera S. Berseneva,
• Vladimir T. Abaev,
• Wim Dehaen and
• Vasiliy A. Bakulev

Beilstein J. Org. Chem. 2026, 22, 192–204, doi:10.3762/bjoc.22.13

• , Leuven B-3001, Belgium 10.3762/bjoc.22.13 Abstract Solvent-dependent transformations of polysubstituted 2-acetyl-2,5-dihydrothiophenes to the corresponding 2-hydroxy- or deacetylated derivatives are described. The treatment of a methanolic solution of the dihydrothiophene substrates with sodium

• methoxide afforded the deacylated products. Conversely, the treatment with sodium ethoxide in an oxygen saturated ethanolic solution produced 2-hydroxy substituted 2,5-dihydrothiophenes. Keywords: 2-acetyl-2,5-dihydrothiophenes; deacylation; 2-hydroxy-2,5-dihydrothiophenes; transformations; Introduction

• S3 of Supporting Information File 1) we have studied their transformations in ethanolic or methanolic solutions in the presence of sodium ethoxide or methoxide, accordingly. As a result, catalyst-free oxidation under mild conditions of 2-acetyl-2,5-dihydrothiophenes into 2-hydroxy-substituted