Synthesis of Dihydropyrans and Dihydrofurans via Radical Cyclization of Unsaturated Alcohols and 1,3-Dicarbonyl Compounds

Aslan H., Akpinar D. E., Oktemer A., YAKUT M., ALAGÖZ O.

HELVETICA CHIMICA ACTA, vol.97, no.5, pp.652-663, 2014 (SCI-Expanded) identifier identifier

  • Publication Type: Article / Article
  • Volume: 97 Issue: 5
  • Publication Date: 2014
  • Doi Number: 10.1002/hlca.201300229
  • Journal Name: HELVETICA CHIMICA ACTA
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus
  • Page Numbers: pp.652-663
  • Keywords: Pyrans, dihydro-, Furans, dihydro-, Cyclization reactions, Manganese(III) acetate, STEREOSELECTIVE-SYNTHESIS, OXIDATIVE CYCLIZATION, AMMONIUM-NITRATE, FACILE SYNTHESIS, RING EXPANSION, DERIVATIVES, ROUTE, 3-OXOPROPANENITRILES, ACETATE, ALKENES
  • Ankara University Affiliated: Yes

Abstract

The oxidative cyclization reactions of 1,3-dicarbonyl compounds 1a-1c and ,-unsaturated alcohols 2a-2f with Mn(OAc)(3) were performed, leading to dihydrofurans. Treatment of 1a and 1b with 2-methylbut-3-en-2-ol (2a) gave dihydrofurans 3aa and 3ba, and dihydropyrans 4aa and 4ba, as unexpected products. While the reaction of 2-methylbut-3-yn-2-ol (2b) with acetylacetone (1b) yielded a bifuran, ethyl acetoacetate (1a) led to a mixture of furan, bifuran, and salicylate derivatives. Besides, surprisingly, styryl-substituted dihydrofurans were obtained from the reactions of 1,3-dicarbonyl compounds and (3E)-2,4-diphenylbut-3-en-2-ol. The reaction mechanisms were proposed for the formation of the different products, considering intermediates in these reaction mixtures.