Major triterpene constituent of cork, obtained by extraction of ground cork with alc. Isoln: Istrati, Ostrogovich, Compt. Rend. 128, 1581 (1899). Isolated also from Ceratopetalum apetalum D. Don, Cunoniaceae: Jefferies, J. Chem. Soc. 1954, 473. Structure, sterochemistry: Brownlie et al., Chem. Ind. (London) 1955, 1156; Kane, Stevenson, Tetrahedron 15, 223 (1961); Stevenson, J. Org. Chem. 28, 188 (1963). Total synthesis of (±)-form: R. E. Ireland, D. M. Walba, Tetrahedron Lett. 1976, 1071.