Asymmetric synthesis of loganin. Stereospecific formation of (1R,2R)- and (1S,2S)-2-methyl-3-cyclopenten-1-ol and (2R)- and (2S)-2-methylcyclopentanone
generate the desired 20‐membered macrolactam. This second‐generation strategy made it possible to prepare synthetic analogues of vicenistatin, including the C20‐ and/or C23‐demethyl analogues. Evaluation of the cytotoxic effect of these analogues indicated the importance of the fixed conformation of aglycon for determining the biological activity of the vicenistatins.
Wolff/Cope Approach to the AB Ring of the Sesterterpenoid Variecolin
作者:Michael R. Krout、Christopher E. Henry、Thomas Jensen、Kun-Liang Wu、Scott C. Virgil、Brian M. Stoltz
DOI:10.1021/acs.joc.7b02972
日期:2018.7.6
A stereoselectivesynthesis of the AB ring of the complex sesterterpenoid variecolin is presented. Our strategy features the development of a tandem Wolff/Cope rearrangement of α-diazo cyclobutyl ketones for the construction of fused, 8-membered carbocycles. Preliminary studies revealed a facile Wolff rearrangement but a difficult vinyl ketene cyclobutane Cope rearrangement. We have leveraged an efficient
Enantioselective opening of cyclic vinyl epoxides with organoaluminium reagents catalysed by copper salts
作者:Olivier Equey、Alexandre Alexakis
DOI:10.1016/j.tetasy.2004.04.011
日期:2004.5
enantioselective conjugate addition of trialkylaluminiumreagents to cyclic vinyl epoxides catalysed by copper salts and chiral phosphorus-based ligands. The reaction must be carried out in THF, otherwise we observed only oligomeric products. The best ees have been obtained with CuTC as the copper salt and a 2,2′-binaphthyl-based phosphorus ligand. Both opening products (SN2 and SN2′ pathways) were
在本文中,我们报道了将三烷基铝试剂对映选择性共轭加成到由铜盐和手性磷基配体催化的环状乙烯基环氧化物中的条件。该反应必须在THF中进行,否则我们只能观察到低聚产物。最好EES已经获得CUTC作为铜盐和2,2- '联萘基磷配位体。两种开放产物(S N 2和S N 2 '途径)均具有良好的对映选择性和中等至良好的区域选择性。
Process for the preparation of methyl
申请人:Hoffmann-La Roche Inc.
公开号:US04174344A1
公开(公告)日:1979-11-13
A process to produce methyl 3,4-anhydro-2,6-dideoxy-L-ribohexopyranoside, its enantiomer and racemate thereof. The compound is useful as an intermediate in the production of daunosamine which in turn is a prime constituent in the anti-cancer agents Daunomycin and Adriamycin. Also disclosed are novel intermediates in the process.