Neighboring Effect of a Carbonyl Group in Base-Induced Wittig-Type Rearrangements of Poly(4-nitrobenzyloxy)tropones to Bis- and Mono(α-hydroxy-4-nitrobenzyl)tropones
作者:Bing Zhu Yin、Akira Mori、Hitoshi Takeshita
DOI:10.1246/bcsj.64.3306
日期:1991.11
The base-catalyzed rearrangement of bis- and tris(4-nitrobenzyloxy)tropones gave (α-hydroxy-4-nitrobenzyl)tropones through a Wittig-type mechanism. Only the 4-nitrobenzyloxy group adjacent to the carbonyl group migrated. The carbonyl group played a role in facilitating the rearrangement by chelation with the sodium on the adjacent carbanion.
Polymer Crystal Engineering for Control of Stereochemical Structure of Polymers: Stereospecific Monomer Synthesis and Stereospecific Solid-State Polymerization
作者:Akikazu Matsumoto、Toshihiro Tanaka
DOI:10.1080/15421400590958539
日期:2005.7.1
polymers according to the monomer configuration and the ester substituents. X-ray single crystalstructure analysis of the monomer and polymer crystals has revealed the process of the topochemical polymerization. In the monomer crystals with 4-alkoxybenzyl groups as the ester substituents, a columnar structure is formed by the alternate stacking of monomer molecules with the aid of weak hydrogen bonds
摘要 我们已经成功地合成了具有各种苄酯基团的 (Z,Z)- 和 (E,E)-粘康酸酯的二等规和二间规聚合物。在室温下,在碳酸钾的六甲基磷酰胺 (HMPA) 中与苄基溴反应时,粘康酸可以方便地转化为其相应的酯衍生物,而无需 EZ 异构化。根据单体构型和酯取代基,几种单体在结晶状态下进行光聚合以得到有规立构聚合物。单体和聚合物晶体的 X 射线单晶结构分析揭示了拓扑化学聚合的过程。在以4-烷氧基苄基为酯基取代基的单体晶体中,柱状结构是由单体分子借助CH/π和CH/O分子间相互作用等弱氢键交替堆叠而成。交替堆叠适用于间规聚合,不同于许多其他酯单体的晶体结构,由于平移单体堆叠在柱中,因此提供二等规聚合物,如 4-氯-、4-溴代和 4-硝基取代的苄酯。弱而灵活的分子间相互作用提供了多种晶体结构和不同类型的分子堆积,导致聚合物的不同立构规整度。不同于许多其他提供二等规聚合物的酯单体的晶体结构,因为平移单体堆积在柱子中,如
Stereospecific Radical Polymerization of Substituted Benzyl Muconates in the Solid State Under Topochemical Control
作者:Akikazu Matsumoto、Toshihiro Tanaka、Kunio Oka
DOI:10.1055/s-2005-865320
日期:——
We have successfully controlled the stereochemical structure of diene polymers during radical polymerization in the solid state under UV and γ-ray radiation. The polymerization of the substitutedbenzyl muconates occurredvia a crystal lattice controlled reaction mechanism. The polymerization is controlled by not only diisotactic and disyndiotactic, but also meso and racemo structures to afford various