Oxatriquinane and Oxatriquinacene: Extraordinary Oxonium Ions
摘要:
Oxatriquinane, a fused, tricyclic alkyl oxonium ion of unprecented stability, was synthesized in five steps from 1,4,7-cyclononatriene. It survives reflux in H2O, chromatography, and attack by alcohols, alkyl thiols, halide ions, and hindered amine bases. The X-ray crystal structure shows longer C-O bond distances and more acute C-O-C bond angles than any reported alkyloxonium salt. The corresponding oxatriquinene and oxatriquinacene were also synthesized and represent the first examples of stable allyl oxonium species.
Oxatriquinane and Oxatriquinacene: Extraordinary Oxonium Ions
作者:Mark Mascal、Nema Hafezi、Nabin K. Meher、James C. Fettinger
DOI:10.1021/ja805686u
日期:2008.10.15
Oxatriquinane, a fused, tricyclic alkyl oxonium ion of unprecented stability, was synthesized in five steps from 1,4,7-cyclononatriene. It survives reflux in H2O, chromatography, and attack by alcohols, alkyl thiols, halide ions, and hindered amine bases. The X-ray crystal structure shows longer C-O bond distances and more acute C-O-C bond angles than any reported alkyloxonium salt. The corresponding oxatriquinene and oxatriquinacene were also synthesized and represent the first examples of stable allyl oxonium species.
1,4,7-Trimethyloxatriquinane: S<sub>N</sub>2 Reaction at Tertiary Carbon
作者:Mark Mascal、Nema Hafezi、Michael D. Toney
DOI:10.1021/ja103880c
日期:2010.8.11
temperatures, but undergoes facile substitution with the strongly nucleophilic azide anion. Since an S(N)1 pathway is excluded, the only reasonable mechanistic interpretation for the reactionbetween 1 and N(3)(-) is S(N)2, despite the fact that substitution is occurring at a tertiary carbon center. This finding is supported by computational modeling and a study of the reactionkinetics, and is also consistent