Lactones 39. Chemical and microbial synthesis of lactones from (−)-α- and (+)-β-thujone

The effective method of isolation, separation and purification of (?)-α- and (+)-β-thujone (1a and 1b) from Thuja occidentalis was elaborated. Chemical (m-CPBA) and microbial Baeyer–Villiger oxidation of (?)-α- and (+)-β-thujone was carried out. Four new bicyclic δ-lactones (2a, 2b, 3a and 3b) with condensed cyclopropane ring were obtained.