An approach of taxol synthesis based on the use of (E)-bis-1,2-(tributylstannyl)ethylene 6 as a readily available two-carbon 1,2-link between A and C-ring is described. The conjugate addition of a mixed higher-order stannylvinyl cyanocuprate derived from 6 on chiral cyclohexenone 5 is completely stereoselective. A model study on 3-methylcyclohex-2-enone showed that the afforded stannylvinyl cyclohexenone
tricycle of Taxol are presented. They both involve a relay ring-closingmetathesis reaction to make the central B ring in a convergent fashion. In the first approach, the extender arm is positioned on the A ring, and the C ring bears the relay tether in the second route. Metathesis precursors with diverse extender arms were efficiently synthesised; unfortunately, the crucial metathesis reactions failed
介绍了两种合成紫杉醇 ABC 三轮车的路线。它们都涉及中继闭环复分解反应,以使中央 B 环以收敛的方式。在第一种方法中,延长臂位于 A 环上,而 C 环在第二种路线中承载中继系绳。高效合成了具有多种扩展臂的复分解前体;不幸的是,关键的复分解反应在所有情况下都未能提供目标化合物。
1,4-dioxene in organic synthesis: Generation and reactivity of epoxydioxenes
作者:Christophe Baylon、Issam Hanna
DOI:10.1016/0040-4039(95)01307-4
日期:1995.9
Oxidation of various alkyldioxens with dimethyldioxirane is described. While pure epoxides were isolated from 4-dioxenylcyclohexanone 10 and diether 9, vinyldioxenes 11–14 gave the corresponding epoxide rearrangement products, α-ketal aldehydes 20–24, in excellent yields.
The first direct synthesis of bicyclo[4.2.0]oct-1(6)-en-7-one
作者:Reijo J Toivola、Satu K Savilampi、Ari M.P Koskinen
DOI:10.1016/s0040-4039(00)01009-1
日期:2000.8
A novel bicyclo[4.2.0]oct-1(6)-en-7-one synthesis and a second characterized member of this class of compounds is described. The process utilizes 2-methylvinyl triflate as the starting material, which is subjected to Pd-catalyzed carbonylation followed by intramolecular cyclization. Further, the reaction of the product with MeOH under different conditions is presented.