Diterpenoids from Croton crassifolius include a novel skeleton possibly generated via an intramolecular [2+2]-photocycloaddition reaction

Five previously undescribed terpenoids named cracrosons D-H, along with 16 known compounds, were isolated from the roots of Croton crassifolius. Cracroson D features a novel carbon skeleton with an unprecedented intramolecular cyclobutane ring.261