Scalable preparation and property investigation of a cis-cyclobutane-1,2-dicarboxylic acid from ß-trans-cinnamic acid.

Scalable synthesis of ß-truxinic acid (CBDA-4) was accomplished by capturing and photodimerizing a metastable crystalline solid of trans-cinnamic acid. This synthetic approach builds a foundation for investigating the properties and applications of the useful diacid. The X-ray crystal structure of CBDA-4 was determined for the first time. The cyclobutane ring in CBDA-4 was cleaved upon heating, making it a promising building block for thermally recyclable/degradable materials.