Nucleophilic Vinylic Substitution on α-Tosyloxymethylene Lactones
Nucleophilic Vinylic Substitution on α-Tosyloxymethylene Lactones
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DOI：
10.1135/cccc19931607
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发表时间：
1993
影响因子：
--
通讯作者：
C. Mazal;J. Jonas
中科院分区：
文献类型：
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作者：
C. Mazal;J. Jonas
通过δ-戊内酯与甲酸乙酯的克莱森缩合获得的3-羟亚甲基四氢-2 H -吡喃-2-酮（V）的钠盐被转化为其磺酸盐和羧酸盐IV、VII - X，它们以纯E -异构体或E -和Z -异构体的混合物形式获得;混合物通过色谱分离。研究了α-对甲苯磺酰氧基亚甲基内酯Ⅱ、Ⅲ、Ⅳ与芳香硫醇、叠氮阴离子、仲胺和烯醇钠XI、XII、V的取代反应。从亲核乙烯基取代反应机理（SNV）的角度讨论了这种取代反应的立体化学结果。
Sodium salt of 3-hydroxymethylenetetrahydro-2 H -pyran-2-one ( V ), obtained by Claisen condensation of δ-valerolactone with ethyl formate, was converted into its sulfonates and carboxylates IV, VII - X , which were obtained either as pure E -isomers or as mixtures of E - and Z -isomers; the mixtures were chromatographically separated. Substitution reaction of α-tosyloxymethylene lactones II, III and IV with aromatic thiols, azide anion, secondary amines and sodium enolates XI, XII and V was studied. The stereochemical outcome of this substitution is discussed from the viewpoint of mechanism of nucleophilic vinylic substitution (S N V).