A cis-3,4-di(furan-2-yl)cyclobutane-1,2-dicarboxylic acid (CBDA-2) is readily prepared stereospecifically from trans-3-(2-furyl)acrylic acid, a furfural-derived compound, through a solid-state [2 + 2] photocycloaddition in 95% isolated yield. The cyclobutane ring in CBDA-2 shows desired stabilities during thermal, sunlight, and chemical tests. The single crystal structure of CBDA-2 revealed the geometry of this molecule and orientation of the two dicarboxylic acid groups displaying its potential to serve as a unique, semirigid diacid building block in material science. A preliminary study showed that condensation of this diacid with glycerol yielded a green polymer with good stability. The diacid could also be used as a cross-linker for a biobased epoxy to yield an exceptionally hard and solvent-resistant thermoset.

中文翻译：

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光反应制备糠醛衍生的二酸用于可持续的材料合成

甲顺-3,4-二（呋喃-2-基）环丁烷-1,2-二羧酸（CBDA-2 ）可容易地从立体有择地制备反式-3-（2-呋喃基）丙烯酸，糠醛衍生的化合物通过固态[2 + 2]光环加成，分离产率为95％。CBDA-2中的环丁烷环在热，日光和化学测试中显示出所需的稳定性。CBDA-2的单晶结构揭示了该分子的几何形状和两个二羧酸基团的方向，显示了其在材料科学中作为独特的半刚性二酸结构单元的潜力。初步研究表明，该二酸与甘油的缩合反应生成的绿色聚合物具有良好的稳定性。该二酸还可用作生物基环氧树脂的交联剂，以产生异常坚硬且耐溶剂的热固性材料。