Generation of carbanions through stibine-metal and bismuthine-metal exchange reactions and its applications to precision synthesis of ω-end-functionalized polymers.
Generation of carbanions through stibine-metal and bismuthine-metal exchange reactions and its applications to precision synthesis of ω-end-functionalized polymers.
复制标题
通过锑-金属和铋-金属交换反应生成碳负离子及其在ω-末端功能化聚合物的精密合成中的应用。
作者：
Eiichi Kayahara;Hiroto Yamada;S. Yamago
从合成和机理的角度研究了通过杂原子-金属交换反应从有机锑和有机二铋生成碳阴离子。用各种有机金属试剂（例如烷基锂、四烷基锌酸盐和烷基卤化镁）处理后，交换反应自发进行，定量产生相应的碳负离子。由于这些杂原子化合物的高反应性，即使存在可能与有机金属物质发生反应的各种极性官能团，交换反应也只能发生。该方法的优点通过在 ω-聚合物末端带有这些杂原子的活性聚合物的端基转化得到了例证，该活性聚合物是通过使用有机锑和铋介导的活性自由基聚合制备的。带有极性官能团和酸性氢的各种聚合物——例如聚（甲基丙烯酸甲酯）、聚（丙烯酸丁酯）、聚（N-异丙基丙烯酰胺）和聚（甲基丙烯酸2-羟乙酯）——可以用于交换反应，随后用亲电子试剂捕获，得到具有受控分子量、分子量分布和端基官能度的相应聚合物。竞争实验表明，有机锑和有机二铋是对有机金属试剂反应性最强的杂原子化合物之一，并且它们的高反应性是交换反应中高化学选择性的原因。
Generation of carbanions from organostibines and organobismuthines through heteroatom-metal exchange reactions was examined from synthetic and mechanistic viewpoints. The exchange reaction proceeded spontaneously upon treatment with various organometallic reagents, such as alkyl lithiums, tetraalkyl zincates, and alkyl magnesium halides to afford the corresponding carbanions quantitatively. Due to the high reactivity of these heteroatom compounds, the exchange reactions took place exclusively even in the presence of various polar functional groups, which potentially react with organometallic species. The advantage of this method was exemplified by the end-group transformation of living polymers that bear these heteroatom species at the ω-polymer end, prepared by using organostibine and bismuthine-mediated living radical polymerizations. Various polymers that bear polar functional groups and acidic hydrogen-for example, poly(methyl methacrylate), poly(butyl acrylate), poly(N-isopropyl acrylamide), and poly(2-hydroxyethyl methacrylate)-could be used in the exchange reactions, and subsequent trapping with electrophiles afforded the corresponding polymers with controlled molecular weights, molecular weight distributions, and end-group functionalities. Competition experiments showed that organostibines and organobismuthines were among the most reactive heteroatom compounds towards organometallic reagents and that their high reactivity was responsible for the high chemoselectivity in the exchange reaction.
影响因子：
15
作者：
Jorgensen, M;Lee, S;Hartwig, JF
通讯作者：
Hartwig, JF