The Synthesis of Heterocycles from Vinylacetylenes or Diacetylenes and Nitrogen-containing Dinucleophiles

Diacetylene: a candidate for industrially important reactions

“…62 ± 67 The structures and reactivities of enamino ketones 6, 18 and ynamino ketones 19 were described in numerous publications. 38,39,52,62 The effects of substituents on the distribution of electron density in the molecules of en-and ynaminocarbonyl compounds were studied by 13 C-NMR spectroscopy. These studies were aimed at the determination of spin-spin coupling constants (J CC ) 13 C7 13 C at the double and triple bonds.…”

“…40 The behaviour of ynamino ketones 19 in cyclisation reactions differs from that of enamino ketones 6 and 18. 38,39,52 Whereas enamino carbonyl compounds typically `deliver' three-carbon fragments in cyclisation, 40 ynamino ketones mostly react like simple ynamines, i.e., with a twofold attack by bifunctional reagents on the carbon atoms of the triple bond (1,1-attack). 52 Thus the reaction of ynamino ketones 19 with ethylenediamine, ethanolamine and 2-mercaptoethanol is accompanied by the elimination of the dialkylamino group and the formation of { Abgas is a technical term, which designates an absorption gas.…”

“…47 1-Alkoxy-and 1-alkylthiobutenynes give a mixture of 3-and 5-methylisoxazoles. 37,38,47 On the other hand, 1-dialkylaminobut-1-en-3-ynes 3 give exclusively 5-methylisoxazole (74) in reaction with hydroxylamine (Scheme 4). 37,47 The latter yields cyanoacetone (75) upon alkaline treatment.…”

4,4-Dialkoxybutan-2-ones as Synthons

“…Franke and Kuther [16] described a procedure for the synthesis of 5-hydroxy-1,1-dimethoxy-5-phenylpentan-3-one (19) from acetal 4a and benzaldehyde through organomagnesium intermediates (Scheme 5).…”