Photochemical access to tetra- and pentacyclic terpene-like products from R-(+)-sclareolide.
Fused tetracyclic oxetanes 4, highly substituted cyclobutenes 6, and the pentacyclic derivatives 7 and 8 were obtained by irradiation of derivatives 3 that were prepared from commercial R-(+)-sclareolide (1) in three steps. Compounds 4 are formed through a Paterno-Büchi reaction, while tricyclic derivatives 6 are the fragmentation products of the first formed oxetanes. In clear contrast, cyclopentenyl and 3-furyl derivatives, 3e and 3f, gave the [2+2] adducts, namely pentacyclic derivatives 7 and 8. All the reported reactions are totally regio- and stereoselective, with the exception of the cyclization of furyl derivative 3f, which gave the mixture of both the crossed (7b) and the right (8) isomers.
de la Torre
María C
MC
Instituto de Química Orgánica, Consejo Superior de Investigaciones Científicas (CSIC), Juan de la Cierva 3, 28006-Madrid, Spain.
García
Isabel
I
Sierra
Miguel A
MA
D004224:Diterpenes / Q000138:chemical synthesis*; D007202:Indicators and Reagents; D008958:Models, Molecular; D015394:Molecular Structure; D010777:Photochemistry; D011083:Polycyclic Compounds / Q000138:chemical synthesis* / Q000737:chemistry; D013237:Stereoisomerism; D013729:Terpenes / Q000138:chemical synthesis* / Q000737:chemistry
D004224:Diterpenes; D007202:Indicators and Reagents; D011083:Polycyclic Compounds; D013729:Terpenes; C109395:sclareolide