Neat cinnamyl fluoride, geranyl fluoride, 5-carbomethoxy-3-fluorocyclohexene and parent 3-fluorocyclohexene undergo spontaneous decomposition on contact with borosilicate glass or catalytic quantities of moderately strong acids that consists in polycondensation with elimination of HF initiated by electrophilic abstraction of F−. Acid sensitivity of these allylicfluorides correlates with stability
A Mild and Efficient Method for the Stereoselective Formation of C−O Bonds: Palladium-Catalyzed Allylic Etherification Using Zinc(II) Alkoxides
作者:Hahn Kim、Chulbom Lee
DOI:10.1021/ol027104u
日期:2002.11.1
[reaction: see text] A highly chemo- and stereoselective palladium-catalyzed allylic etherification reaction is described. The use of zinc(II) alkoxides proved effective in promoting the addition of the oxygen nucleophile derived from aliphatic alcohols to eta(3)-allylpalladium complexes. Using diethylzinc (0.5 equiv), 5 mol % of Pd(OAc)(2), and 7.5 mol % of 2-di(tert-butyl)phosphinobiphenyl in THF
Studies on the Narciclasine Alkaloids: Total Synthesis of (+)-Narciclasine and (+)-Pancratistatin
作者:James H. Rigby、Umar S. M. Maharoof、Mary E. Mateo
DOI:10.1021/ja000930i
日期:2000.7.1
Enantioselective total syntheses of the antitumor alkaloids, (+)-narciclasine and (+)-pancratistatin, are reported. These syntheses feature a stereo- and regiocontrolled aryl enamide photocyclization to construct a common, advanced intermediate possessing a trans-fused BC substructure. Differential functional group interchange in the C-ring of this phenanthridone core structure allows for the production
报道了抗肿瘤生物碱 (+)-narciclasine 和 (+)-pancratastatin 的对映选择性全合成。这些合成具有立体和区域控制的芳基烯酰胺光环化,以构建具有转融合 BC 亚结构的通用高级中间体。这种菲啶酮核心结构的 C 环中的差异官能团交换允许以对映异构纯形式生产两种目标天然产物。
Palladium-Catalyzed Asymmetric Synthesis of Allylic Fluorides
作者:Matthew H. Katcher、Abigail G. Doyle
DOI:10.1021/ja109120n
日期:2010.12.15
The enantioselective fluorination of readily available cyclic allylic chlorides with AgF has been accomplished using a Pd(0) catalyst and Trost bisphosphine ligand. The reactions proceed with unprecedented ease of operation for Pd-mediated nucleophilic fluorination, allowing access to highly enantioenriched cyclic allylicfluorides that bear diverse functional groups. Evidence that supports a mechanism