报道了 (-)-englerin A ( 1 )的有效形式合成。目标分子是最近分离的愈创木酚倍半萜烯,它对肾癌细胞系具有高效和选择性的活性。我们的对映选择性策略涉及通过 Rh II构建化合物1的 BC 环系统-催化的 [4+3] 环加成反应,随后通过分子内醛醇缩合反应连接 A 环。因此,该策略允许合成截断的 englerins。用 A498 肾癌细胞系对这些类似物进行评估表明,englerin 的 A 环对其抗增殖活性至关重要。此外,对这些类似物的评估导致鉴定了 CEM 细胞的强效生长抑制剂,其 GI 50值在 1-3 μM范围内。
Asymmetric Synthesis of Highly Functionalized 8-Oxabicyclo[3.2.1]octene Derivatives
作者:Huw M. L. Davies、Gulzar Ahmed、Melvyn Rowen Churchill
DOI:10.1021/ja962081y
日期:1996.1.1
Asymmetric synthesis of the oxabicyclic products is possible through utilization of rhodium(II) (S)-N-(tert-butylbenzene)sulfonylprolinate as catalyst or by using (S)-lactate or (R)-pantolactone as chiral auxiliaries on the carbenoid. The highest yields (69−95%) and asymmetric induction (82−95% de) were obtained using 3-siloxy-2-diazo-3-butenoate derivatives as the vinylcarbenoid precursors.
Catalyzed addition of diazoacetoacetates to imines: synthesis of highly functionalized aziridines
作者:Xue-jing Zhang、Ming Yan、Dan Huang
DOI:10.1039/b813763c
日期:——
The addition of diazoacetoacetates to aromatic imines derived from p-methoxyaniline is achieved using dirhodium tetraacetate as the catalyst. Highly functionalized aziridines are obtained in good yield and with excellent stereoselectivity. 2-Diazo-1,3-diketones also provide good yields of aziridines, but dimethyl diazomalonate is inactive in the transformation. The diazoacetoacetates of chiral alcohols are also examined in the reaction and moderate diastereoselectivity is achieved with (R)-pantolactone-derived diazoacetoacetate. A reaction mechanism through metal-carbene and azomethine ylide is proposed.
Asymmetric Synthesis of 2,3-Dihydrofurans by Reaction of Rhodium-Stabilized Vinylcarbenoids with Vinyl Ethers
作者:Huw M. L. Davies、Gulzar Ahmed、Rebecca L. Calvo、Melvyn Rowen Churchill、David G. Churchill
DOI:10.1021/jo972189b
日期:1998.4.1
Rhodium(II) octanoate catalyzed decomposition of 2-diazo-3-siloxybutenoates, containing (R)-pantolactone as a chiral auxiliary, in the presence of vinylethers results in the diastereoselective synthesis of cyclopropanes with high asymmetric induction. Treatment of the cyclopropanes with tetrabutylammonium fluoride results in desilylation and ring expansion of the resulting acylcyclopropanes to 2,3-dihydrofurans
Enantioselective Synthesis of Functionalized Tropanes by Rhodium(II) Carboxylate-Catalyzed Decomposition of Vinyldiazomethanes in the Presence of Pyrroles
作者:Huw M. L. Davies、Julius J. Matasi、L. Mark Hodges、Nicholas J. S. Huby、Craig Thornley、Norman Kong、Jeffrey H. Houser
DOI:10.1021/jo961920w
日期:1997.2.1
A series of enantiomerically enriched tropanes was synthesized by the rhodium(II) octanoate-catalyzed reaction of various N-BOC-protected pyrroles with vinyldiazomethanes. The overall 3 + 4 annulation occurs by a tandem cyclopropanation/Cope rearrangement. Asymmetric induction was best achieved in these transformations by using either (S)-lactate or (R)-pantolactone as a chiral auxiliary on the vinyldiazomethanes. Reactions carried out with the chiral catalyst tetrakis[N-( 4-tert-butylbenzenesulfonyl)-(L)-prolinato]dirhodium (2) provided moderate asymmetric induction, but also resulted in the formation of isomeric azabicyclooctane side products. The utility of the synthetic process was demonstrated through the asymmetric synthesis of(-)-anhydroecgonine methyl ester and (-)-ferruginine.
Enantioselective synthesis of tropanes by reaction of rhodium-stabilized vinylcarbenoids with pyrroles
作者:Huw M.L. Davies、Nicholas J.S. Huby
DOI:10.1016/s0040-4039(00)60899-7
日期:1992.11
Rhodium(II) catalyzed decomposition of vinyldiazomethanes containing either (R)-pantolactone or (S)-lactate as chiral auxiliary in the presence of N-(tert-butoxycarbonyl)pyrrole resulted in an enantioselective entry to tropanes by a tandem cyclopropanation/Cope rearrangement.