A reaction of organic dichalcogenides R2Y2 (R = Ph, Bn, Pr; Y = S, Se) with 1,4-dichlorobut-2-yne in the system hydrazine hydrate–KOH leads to four principal products: 1,4-bis(organylchalcogenyl)but-2-ynes, 1-organylchalcogenylbut-1-en-3-ynes, 4-organylchalcogenylbut-1-en-3-ynes, and 3(5)-methylpyrazole. The selectivity of the formation of individual products is determined by the ratio of the substrates used and the reaction temperature. A plausible mechanism of chalcogenation considered in the work agrees with the effect of the nature of chalcogene atoms and organic substituents R on stability of intermediates and products. The stabilization of carbanions by α chalcogene-containing groups corresponds to the following order: PhS > PhSe > BnS > BnSe > PrS.
有机二磺
酰亚胺R2Y2(R=Ph、Bn、Pr;Y=S、Se)与1,4-二
氯丁炔-2在系统联
氨氢
水合物-KOH中的反应主要产生四种产物:1,4-双(有机磺
酰亚胺基)丁炔-2、1-有机磺
酰亚胺基
丁烯-1-炔-3、4-有机磺
酰亚胺基
丁烯-1-炔-3和3(5)-甲基
吡唑。单个产物的选择性取决于所用底物的比例和反应温度。本文考虑的加磺
酰亚胺化作用的可行机制与磺
酰亚胺原子和有机取代基R的性质对中间体和产物稳定性的影响相符。由α-磺
酰亚胺基团稳定碳阴离子的顺序为:PhS > PhSe > BnS > BnSe > PrS。