Gowda Ravikumar R, Chen Eugene Y-X
Department of Chemistry, Colorado State University, Fort Collins, CO 80523-1872, USA
Philos Trans A Math Phys Eng Sci. 2017 Aug 28;375(2101). doi: 10.1098/rsta.2017.0003.
Multivinyl-functionalized γ-butyrolactones, γ-vinyl-γ-methyl-α-methylene-γ-butyrolactone (VMMBL) and γ-allyl-γ-methyl-α-methylene-γ-butyrolactone (AMMBL), have been synthesized from biorenewable ethyl levulinate and effectively polymerized by Lewis pairs consisting of an organic -heterocyclic carbene Lewis base and a strong organo-Lewis acid E(CF) (E = Al, B). This Lewis pair polymerization is quantitatively chemoselective, proceeds exclusively via polyaddition across the conjugated α-methylene double bond without participation of the γ-vinyl or γ-allyl double bond, and produces high-molecular-weight functionalized polymers with unimodal molecular-weight distributions. The Al-based Lewis pair produces a polymer with approximately 5.5 times higher molecular weight than that produced by the B-based Lewis pair. The resulting vinyl-functionalized polymers are soluble in common organic solvents and stable at room temperature, and can be thermally cured into crosslinked materials.This article is part of the themed issue 'Frustrated Lewis pair chemistry'.
多乙烯基官能化的γ-丁内酯，γ-乙烯基-γ-甲基-α-亚甲基-γ-丁内酯（VMMBL）和γ-烯丙基-γ-甲基-α-亚甲基-γ-丁内酯（AMMBL），已由生物可再生的乙酰丙酸乙酯合成，并通过由有机杂环卡宾路易斯碱和强有机路易斯酸E(CF)（E = Al、B）组成的路易斯对有效地聚合。这种路易斯对聚合是定量化学选择性的，仅通过共轭α-亚甲基双键的加成聚合进行，而γ-乙烯基或γ-烯丙基双键不参与，并且产生具有单峰分子量分布的高分子量官能化聚合物。基于Al的路易斯对比基于B的路易斯对产生的聚合物分子量高约5.5倍。所得的乙烯基官能化聚合物可溶于常见有机溶剂且在室温下稳定，并且可以热固化成交联材料。本文是主题为“受阻路易斯对化学”的特刊的一部分。
