Alkylation of β-dicarbonyl compounds as a method for the production of functionally substituted dihydrofurans

Abstract

The alkylation of some representatives of β-dicarbonyl compounds by 1,4-dibromo-2-butene and ethyl 2,3-dibromopropionate was investigated.Furans represent one of the important classes of heteroaromatic compounds. Substituted furans are usually synthesized by the regioselective insertion of carbon substituents into furan or its acyclic precursors [1]. Universal and convenient synthons for the "construction" of furans and related heterocycles containing an acyl group at position 3 of the heterocycle are β-dicarbonyl compounds. In recent years [2-4] a series of reviews have been published on numerous methods for the synthesis of furans from 1,3-diketones, which are valuable intermediates in the synthesis of liquid crystals, various heterocycles, and physiologically active substances and particularly pheromones and prostaglandins [5][6][7][8].We investigated the alkylation of some representatives of β-dicarbonyl compounds by various dihalides in order to obtain functionally substituted dihydrofurans.While continuing study of the reactivity of β-dicarbonyl compounds [9, 10] we realized the reactions of dimedone, allyl acetoacetate, acetylacetone, and acetoacetic ester with ethyl 2,3-dibromopropionate (1) and 1,4-dibromo-2-butene (2) in the K 2 CO 3 -DMSO system. It was established that the alkylation of dimedone with compounds 1 (Scheme 1) and 2 (Scheme 2) takes place exclusively in the direction of C,O-cycloalkylation with the formation of 2-ethoxycarbonyl-6,6-dimethyl-2,3,4,5,6,7-hexahydrobenzo[b]furan-4-one (3) and 6,6-dimethyl-2-vinyl-2,3,4,5,6,7-hexahydrobenzo[b]furan-4-one (9) respectively.In the reaction of allyl acetoacetate with the ester 1 we obtained 4-allyloxycarbonyl-2-ethoxycarbonyl-5-methyl-2,3-dihydrofuran (4).

Some Acetophenone Derivatives as Corrosion Inhibitors

“…In the previous works we informed about the synthesis and NMR investigations of different acetophenone derivatives [18][19][20][21][22][23][24][25][26][27][28].…”

Synthesis of New Pyrane and Cyclohexanone Derivatives on the Base of Some Knoevenagel Adducts

“…In the literatures there are a lot of information on synthesis and various transformation of this type compounds [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15]. Also, the Michael addition is the fundamental reaction of formation of C-C bond in organic synthesis and we discussed it in early investigations [16][17][18][19][20][21][22][23][24][25][26][27][28][29].…”