Application of palladium-catalyzed cycloalkenylation reaction to terpenoid synthesis—novel approach to tricyclo[5.3.1.02,6]undecane derivative and its transformation into bicyclo[5.3.1]undecane ring system

✍ Scribed by Masahiro Toyota*; Marcellino Rudyanto; Masataka Ihara

• Publisher: Elsevier Science
• Year: 2000
• Tongue: French
• Weight: 100 KB
• Volume: 41
• Category: Article
• ISSN: 0040-4039
• DOI: 10.1016/s0040-4039(00)01609-9

✦ Synopsis

A novel synthesis of the tricyclo[5.3.1.0 2,6 ]undecane compound 16, basic carbon skeleton of gymnomitrane class of sesquiterpenoids, and the transformation into the bicyclo[5.3.1]undecane derivative 18, the AB carbon framework of taxol (6), have been achieved. Beginning with the bicyclo[3.2.1]octane ring system 2, prepared from the cross-conjugated silyl enol ether 1 employing palladium-catalyzed cycloalkenylation reaction, the tricyclo[5.3.1.0 2,6 ]undecane ring system 16 was synthesized by using samarium-promoted reductive cyclization of 15. After conversion of 16 to the hydroxy tosylate 17, basic treatment of 17 afforded the desired bicyclo[5.3.1]undecane derivative 18. Interestingly, the highly strained oxetane 19 was also obtained together with 18.