Synthesis of Hexacyclo(5.4.0.0(2,6).0(3,10).0(5,9).0(8,11)undecane-8-carboxylic Acid) (Homopentaprismane-8-carboxylic Acid).

摘要

The title compound was synthesized in nine steps from pentacyclo(5.4 .0.0(2,6).0(3,10).0(5,9))- undecane-8, 11-dione monoethylene ketal (2) in 23% overall yield. Thus, reaction of 2 with ethyl (diethoxyphosphinyl) acetate in the presence of NaH provided the corresponding 8-carboethoxymethylene derivative (3, 93%). The corresponding endo-11-carboethoxy-methylene derivative (4, 100%) was prepared via catalytic hydrogenation of 3. Hydrolysis of the ester and ketal groups in 4 with aqueous acid gave 5 (90%). The corresponding substituted 1,3-dishomopentaprismane (6,91%) was synthesized by subsequent reaction of 5 with NaH/DMF-THF. Reaction of 6 with MeLi/THF gave 7 (80%), which, upon oxidation with CF3CO3H followed by workup with aqueous base afforded the corresponding 1,3-bishomo-pentaprismanediol (8, 60%). Organic chemistry.