高分子 Vol.72 No.6
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特集 重合反応の解明と精密構造制御への取り組み
展望 COVER STORY: Highlight Reviews
Rapid Synthesis of Middle-Size Biomolecules Comprising of a Repeating Structure
小山 靖人
Yasuhito KOYAMA
<要旨> 中分子サイズの天然物の合成には通常、多段階合成が必要となる。中分子の物性評価や実用化のために、省力的な大量合成法の開発が求められている。ここでは、天然中分子の繰り返し構造のための迅速・簡便な合成手法を紹介する。低分子と高分子の狭間にある中分子の合成法を眺め、精密高分子合成の今後の役割について考える。
Keywords: Middle-Size Biomolecules / Polypeptide / Deoxypropionate / Poly(Cyclic Ether) / Oligosaccharide / Glycoside / Terpenoid / Polyketide
Advances in Polymerization of Aromatic Acetylenes
谷口 剛史・西村 達也・前田 勝浩
Tsuyoshi TANIGUCHI, Tatsuya NISHIMURA, Katsuhiro MAEDA
<要旨> 近年、ポリアセチレン類を基盤とした材料開発に向けた研究が活発に行われているが、ポリアセチレン類の高度な機能化を実現するためには、アセチレン類の精密重合法の開発が不可欠である。本稿では、芳香族アセチレン類の重合反応に焦点を当て、これまでの問題点と、それらを解決するべく進められている最近の研究について紹介する。
Keywords: Polyacetylenes / Polymerization / Living Polymerization / Polymerization Mechanism / Rhodium / Tungsten / Tantalum
Organic Synthesis of Medium Molecules: Electrochemical Amide Bond Formations
岡田 洋平
<要旨> 低分子と高分子の間に位置する「中分子」サイズの化合物群が次世代の医薬品候補として大きな注目を集めている。生体高分子の「有機合成」はきわめて困難であるが、中分子サイズであればどうだろうか。本稿ではとくにペプチドに焦点を当てて、近年の有機合成研究について簡単に紹介する。筆者の個人的な見解が多く含まれていることにも留意されたい。
Keywords: Organic Synthesis / Medium Molecule / Electrochemistry / Amide Bond Formation / Peptide / Liquid Phase / Soluble Tag
トピックス COVER STORY: Topics and Products
Simultaneous Control of Molecular Weights and Stereo-Strctures by Degenerative Chain-Transfer Cationic Polymerizations
内山 峰人
<要旨> Recently, we developed novel living cationic polymerizations that proceed via degenerative chain-transfer (DT) mechanisms using thioesters and thioethers as reversible chain-transfer agents in the presence of various cationic initiators. This article describes our recent research about the simultaneous control of molecular weight and stereo-structures using cationic reversible addition-fragmanetation chain transfer (RAFT) or DT polymerizations. Stereospecific cationic RAFT polymerization was achieved by combining cationic RAFT polymerization with thioesters and stereospecific cationic polymerization of bulky vinyl ethers with Lewis acid catalysts. The molecular weight was controlled by the RAFT process whereas the tacticity was controlled by stereospecific propagation based on the steric hindrance of bulky side groups and counteranions derived from the Lewis acid catalyst. In addition, the cationic DT process is also applicable to asymmetric cationic polymerization of benzofuran by combination of Lewis acid catalysts and chiral additives to achieve the dual control of molecular weight and optical activity of the resulting polymers.
Keywords: Living Polymerization / Cationic Polymerization / Degenerative Chain-Transfer / RAFT Polymerization / Stereospecific Polymerization / Poly(vinyl Alcohol) / Asymmetric Polymerization / Benzofuran
Design of Photocatalysts for Polymer Synthesis Using Visible-Light as External Stimulus
稲垣 昭子
<要旨> In the field of homogeneous catalysis, various efficient photoredox reactions have been developed, in which mainly ruthenium and iridium visible-light sensitizers play the key roles in the catalysis to promote single electron transfer to generate reactive radical species under mild conditions. Apart from these reactions, utilization of the excited-state of the catalyst itself may lead to new type light-controlled reactions. In order to realize such reactions, precise design of the photocatalysts is inevitable for the efficient formation of the desired excited-state. Our intensive studies on developing new visible-light driven catalysts are described here. Utilization of a bichromophore unit in order to extend the excited-state lifetime was successful to realize high reactivity of the Ir-Pd catalyst toward styrene polymerization. Visible-light irradiation intensively drives the polymerization because of producing a highly active excited state for monomer insertion. The character of the catalyst can be used to tune the copolymerization reaction to yield copolymers with different co-monomer content and glass-transition temperature.
Keywords: Visible-Light Energy / Photocatalyst / Dinuclear Catalyst / Photosensitizer / Bichromophore / Polymerization / Excited-State Lifetime / Ruthenium / Iridium / Copper Photosensitizers
One-Pot Synthesis of Sequence-Controlled Oligosiloxanes
松本 和弘
<要旨> A wide variety of sequence-defined oligosiloxanes can be synthesized by one-pot controlled iteration of B(C6F5)3-catalyzed dehydrocarbonative condensation of alkoxysilanes with hydrosilanes and hydrosilylation of carbonyl compounds.
Keywords: Oligosiloxanes / Siloxanes / One-Pot Synthesis / Controlled Iteration
グローイングポリマー Polymer Science and I: A Personal Account
Number of Moves
村山 恵司
<要旨> I believe that the most important point for research is the number of experiments carried out. I performed a lot of experiments as a student, which resulted in successful development of novel Xeno Nucleic Acids. No one can accurately predict the results. The number of experiments promises the success.
高分子科学最近の進歩 Front-Line Polymer Science
Multicomponent Supramolecular Nanobiomaterials
東 小百合・池田 将
Sayuri L. HIGASHI, Masato IKEDA
<要旨> Biomolecular assemblies inside living cells have inspired us to design self-assembling molecules capable of showing orthogonal self-assembly and/or stimuli-responsive and energy dissipative self-assembling phenomena, which may lead to the construction of intelligent supramolecular nanobiomaterials as well as artificial cells. Here, we highlight recent papers including those from our group, in which research on the two topics, i.e., orthogonal/dissipative self-assembly, with synthetic self-assembling molecules have been conducted.
Keywords: Supramolecular Materials / Self-Assembly / Nanostructures / Orthogonal / Dissipative / Biomolecular Sciences