Synthesis of the ABC Fragment of the Pectenotoxins
作者:Rosliana Halim、Margaret A. Brimble、Jörn Merten
DOI:10.1021/ol0507975
日期:2005.6.1
[reaction: see text] A highly stereocontrolled synthesis of the C1-C16 ABC spiroacetal-containing fragment 5 of PTX7 (4) has been achieved. Appendage of the C ring to the AB fragment involved Wittigreaction of spiroacetal aldehyde 8 with a stabilized ylide 9 followed by displacement of allylic iodide 27 with a lithium acetylide to afford enyne 7. Fructose-derived chiral dioxirane and dihydroxylation
Synthesis of the ABC tricyclic fragment of the pectenotoxins via stereocontrolled cyclization of a γ-hydroxyepoxide appended to the AB spiroacetal unit
作者:Rosliana Halim、Margaret A. Brimble、Jörn Merten
DOI:10.1039/b600951d
日期:——
spiroacetal fragment was achieved viaaddition of acetylene 11 to the unstable allylic iodide 39. Epoxidation of (E)-enyne 8 via in situ formation of L-fructose derived dioxirane generated the desired syn-epoxide 36. Semi-hydrogenation of the resulting epoxide 36 followed by dihydroxylation of the alkene effected concomitant cyclization, thus completing the synthesis of the ABC spiroacetal ring fragment