本文中,我们描述了一种环境友好且具有成本效益的方案,用于合成有价值的呋喃二甲酸二羧酸酯,首先是通过LiBr和K 2 S 2 O 8对易得的呋喃-2-羧酸酯进行α-溴化反应。此外,然后在醇存在下,在钯催化的还原均偶联反应中进行溴化中间产物5-溴呋喃-2-羧酸酯的合成,得到双呋喃基二羧酸酯。该协议的最终产品之一,[2,2'] bifuran-5,5'-二羧酸酯是聚(呋喃二甲酸乙二酯)的重要单体,可用作传统聚对苯二甲酸乙二醇酯的绿色多用途替代聚合物。 (对苯二甲酸乙二醇酯)目前在工业塑料中很常见。
Atmospheric oxygen was used for the first time as an oxidant in metal-catalyzed homocoupling of Grignard reagents. These manganese- or iron-catalyzed reactions are efficient, cheap, and eco-friendly. They are applicable to the large-scale synthesis of symmetrical conjugated compounds.
Efficient homo-coupling reactions of heterocyclic aromatic bromides catalyzed by Pd(OAc)2 using indium
作者:Kooyeon Lee、Phil Ho Lee
DOI:10.1016/j.tetlet.2008.04.123
日期:2008.6
Homo-coupling reactions of heterocyclic aromatic bromides smoothly proceeded with cat-Pd(OAc)2, indium, and LiCl in DMF to afford exclusively symmetric biaryls possessing heterocyclic aromatic ring in good to excellent yields.
Oxidative heterocoupling between two Grignardreagents RMgX and R′MgX is made possible by manganese catalysis with O2 as an oxidant. This procedure, development of which was based on mechanistic analysis of the corresponding homocoupling reaction, can be steered towards the heterocoupling product at the expense of the homocoupling products by judicious choice of the R and R′ groups (see examples).
Preparation of Furan Dimer-based Biopolyester Showing High Melting Points
作者:Naoki Miyagawa、Tadayuki Ogura、Kentaro Okano、Takuya Matsumoto、Takashi Nishino、Atsunori Mori
DOI:10.1246/cl.170647
日期:2017.10.5
Treatment of the obtained diester with 1,ω-diol in the presence of titanium alkoxide as a catalyst leads to the corresponding polyester in excellent yields. The obtained polymers show remarkably high meltingpoints compared with the related polyesters composed of a single furan ring derived from furan-2,5-dicarboxylic acid (FDCA). Thermal properties of the furan dimer-derived polyesters are comparable with