Reactions of 1-nitro-2-sulfonylalkenes with arenethiolates result in replacement of the sulfonyl group; the reactions with alkanethiolates are accompanied by subsequent addition of the reagent at the double bond to afford thioacetals. Less reactive alpha-nitro-beta-R-thiostyrenes with thiolates at reduced temperature form addition products which are converted into the corresponding substitution products on storage at room temperature, in keeping with the addition-elimination mechanism of nucleophilic vinyl substitution. Nitro(aryl-thio)- and nitro(heterylthio)alkenes react with alkanethiolates at room temperature, resulting in replacement of the arylthio (heterylthio) group by alkylthio.
Stereochemistry in Nucleophilic Vinylic Substitution of Activated Nitro Olefins
作者:Kyong Pae Park、Hyun-Joon Ha
DOI:10.1246/bcsj.63.3006
日期:1990.10
Each of E and Z-isomers of activated α,β-dinitro olefins and α-iodo-β-nitrostilbene reacted ith several different types of nucleophiles such as amines, thiocyanate, and p-toluenethiolate. Only Z-isomers of vinylic-substituted olefins with amines and thiocyanate were observed as products due to the attractive interactions between the nitro group of substrate and the nucleophile in the intermediate state
活化的 α,β-二硝基烯烃和 α-碘-β-硝基二苯乙烯的 E 和 Z 异构体中的每一种都与几种不同类型的亲核试剂反应,如胺、硫氰酸盐和对甲苯硫醇盐。由于底物的硝基与中间状态的亲核试剂之间的吸引力相互作用,仅观察到带有胺和硫氰酸酯的乙烯基取代烯烃的 Z-异构体作为产物。p-Toluenethiolate 作为亲核试剂不能产生足够强的相互作用以产生单个 Z 产物,而是产生收敛的 (E) 和 (Z) 产物混合物。尽管如此,还是倾向于 Z 型配置。