These compounds are obtained by the [2 + 2] photocycloadditions of cinnamic acid where the two trans alkenes react head-to-tail.

[1] The preparation of truxillic acids provided an early example of organic photochemistry.

[3][4] Incarvillateine, an alkaloid from the plant Incarvillea sinensis, is a derivative of α-truxillic acid.

[6][7] Below are the five stereoisomers of truxillic acid, called alpha, gamma, epsilon, peri, and epi.

These are shown both in a 2D skeletal diagram with stereocenters indicated and a 3D rendering of the structural geometry of the isomers themselves.