Five-membered ring annulation via thermal rearrangement of β-cyclopropyl α,β-unsaturated ketones. A formal total synthesis of the sesquiterpenoid (±)-zizaene
作者:Edward Piers、Jacques Banville、Cheuk Kun Lau、Isao Nagakura
DOI:10.1139/v82-425
日期:1982.12.1
1-one (16) was allowed to react with dimethyloxosulfonium methylide in dimethyl sulfoxide – tetrahydrofuran, 3-(1-methylcyclopropyl)-2-cyclohexen-1-one (17) was produced in 59% yield. Although thermal rearrangement (~425–450 °C) of compounds 11 and 17 produced high yields of the annulation products 19 and 22, respectively, similar reactions involving the β-cyclopropyl enones 12 and 13 were not efficient
synthetically challenging seven/eight-membered fused carbocycles through rhodium-catalyzed coupling between 4σ-donor (benzocyclobutenones) and pendant diene (4π) motifs in good yields (up to 90 %). A mechanism was proposed based on kinetic and 13C-labeling experiments. Notably, one product was found to be a potent and selective liver X receptor β binding ligand (KD=0.64 μM).
开发了 I 型 [4σ+4π] 和 [4σ+4π−1] 环加成,通过 4σ-供体(苯并环丁烯酮)和侧链二烯 (4π) 基序之间的铑催化偶联,获得具有合成挑战性的七/八元稠合碳环。产率(高达 90%)。基于动力学和13 C 标记实验提出了一种机制。值得注意的是,一种产品被发现是一种有效的、选择性的肝脏 X 受体 β 结合配体 (KD=0.64 μM)。
Total synthesis of (.+-.)-modhephene and its epimer, (.+-.)-epimodhephene
作者:Amos B. Smith、Paula J. Jerris
DOI:10.1021/jo00349a008
日期:1982.5
Formation of Quaternary Stereogenic Centers by NHC-Cu-Catalyzed Asymmetric Conjugate Addition Reactions with Grignard Reagents on Polyconjugated Cyclic Enones
The copper‐catalyzedconjugateaddition of various Grignard reagents to polyconjugated enones (dienone and enynone derivatives) is reported. The catalyst system, composed of copper triflate and an NHC ligand, led to the unusual selective formation of the 1,4‐addition products. This reaction allows for the creation of all‐carbon chiral quaternary centers with enantiomeric excesses up to 99 %. The remaining
作者:Louis Barriault、Jermaine D. O. Thomas、Roxanne Clément
DOI:10.1021/jo020664m
日期:2003.3.1
The successful stereocontrol of the Diels-Alderreaction of semicyclicdienes possessing a secondary and tertiary allylic magnesium alkoxide alcohol functionality and activated dienophiles such as methyl acrylate, methacrolein, acrolein, and N-phenylmaleimide is described.