Facile Construction of the Tricyclo[5.2.1.0<sup>1,5</sup>]decane Ring System by Intramolecular Double Michael Reaction: Highly Stereocontrolled Total Synthesis of (±)-8,14-Cedranediol and (±)-8,14-Cedranoxide
作者:Masataka Ihara、Kei Makita、Kiyosei Takasu
DOI:10.1021/jo981996n
日期:1999.2.1
It was observed that the synthesis of tricyclo[5.2.1.0(1,5)]decane 10 can be performed effectively by the intramolecular double Michael reaction of 5-(5-methoxycarbonyl-4-pentenyl)-2-cyclopenten-1-one (9). Highly stereocontrolled total syntheses of(+/-)-8, 14-cedranediol (2) and (+/-)-8,14-cedranoxide (1) were accomplished by the application of this methodology. Heating 5-(1,5-dimethyl-5-ethoxycarbonylpent-4-enyl)-2-cyclopenten-1-one (15) with TMSCl, Et3N, and ZnCI2 in o-dichlorobenzene at 150 degrees C provided (+/-)-(1R*, 2R*, 5R*, 6R*, 7S*)-2,6-dimethyl-6-ethoxycarbonyltricyclo[5.2.1.0(1,5)]- decan-9-one (16) as a single isomer. The product 16 was stereoselectively converted into the above cedranoids 2 and 1 through ring expansion chemistry.