HELVETICA CHIMICA ACTA, cilt.97, sa.5, ss.652-663, 2014 (SCI-Expanded)
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.