通过重氮前体的光解在甲醇中生成具有不饱和邻位取代基(乙烯基氧基、1-丙烯氧基、烯丙基、2-丁烯基、2,4-戊二烯基)的芳基卡宾。发现分子间 OH 插入与双键的分子内加成竞争。与类似的分子间反应相比,三线态敏化强烈影响产物分布。根据 k S /k ST 和 k T /k TS 速率比对分子内过程的单线态和三线态成分进行剖析和评估。单线态芳基卡宾的分子内环加成反应效率很低,可能是由于需要围绕外环 C-CH: 键旋转。相比之下,相对于分子间类似物,三重芳基卡宾的非集中分子内加成强烈加速。最有可能的,
通过重氮前体的光解在甲醇中生成具有不饱和邻位取代基(乙烯基氧基、1-丙烯氧基、烯丙基、2-丁烯基、2,4-戊二烯基)的芳基卡宾。发现分子间 OH 插入与双键的分子内加成竞争。与类似的分子间反应相比,三线态敏化强烈影响产物分布。根据 k S /k ST 和 k T /k TS 速率比对分子内过程的单线态和三线态成分进行剖析和评估。单线态芳基卡宾的分子内环加成反应效率很低,可能是由于需要围绕外环 C-CH: 键旋转。相比之下,相对于分子间类似物,三重芳基卡宾的非集中分子内加成强烈加速。最有可能的,
o-Allyloxyanisoles are selectively and easily deallylated by treatment with sec- or tert-butyllithium at low temperature. The reaction is proposed to proceed through a tandem intermolecular carbolithiation-β-elimination process, which can also be considered an SN2′ attack of the organolithium on the allyl ether.
Intramolecular reactivity of functionalized arylcarbenes: 2-allyloxyphenylcarbenes
作者:Frank Gotzhein、Wolfgang Kirmse
DOI:10.1016/s0040-4039(97)00090-7
日期:1997.2
2-Allyloxyphenylcarbenes (8) undergo intramolecular addition (→ 9) and (formal) CH insertion (→ 11) competitively. Stereochemical labels indicate that 11 and major amounts of 9 arise from triplet 8. The intermolecular OH insertion of singlet 8 with methanol (neat) is ca. 50 times faster than intramolecular addition. Under these conditions, intramolecular reactions and intersystem crossing of triplet
Intramolecular addition reactions of functionalized arylcarbenes to double bonds
作者:Wolfgang Kirmse、Guenter Hoemberger
DOI:10.1021/ja00010a038
日期:1991.5
was found to compete with intramolecular addition to the doublebonds. The product distributions are strongly affected by triplet sensitization, in contrast to those of analogous intermolecular reactions. The singlet and triplet components of the intramolecular processes were dissected and evaluated in terms of k S /k ST and k T /k TS rate ratios. Intramolecularcycloaddition reactions of singlet arylcarbenes
通过重氮前体的光解在甲醇中生成具有不饱和邻位取代基(乙烯基氧基、1-丙烯氧基、烯丙基、2-丁烯基、2,4-戊二烯基)的芳基卡宾。发现分子间 OH 插入与双键的分子内加成竞争。与类似的分子间反应相比,三线态敏化强烈影响产物分布。根据 k S /k ST 和 k T /k TS 速率比对分子内过程的单线态和三线态成分进行剖析和评估。单线态芳基卡宾的分子内环加成反应效率很低,可能是由于需要围绕外环 C-CH: 键旋转。相比之下,相对于分子间类似物,三重芳基卡宾的非集中分子内加成强烈加速。最有可能的,