Preparation of Oxepanes, Oxepenes, and Oxocanes by Iodoetherification using Bis(sym-collidine)iodine(I) Hexafluorophosphate as Electrophile
摘要:
Oxepanes have been obtained in good yields (40-95%) by iodoetherification of unsaturated alcohols using bis(sym-collidine)iodine(I) hexafluorophosphate (1) as electrophile, either by 7-exo-mode or 7-endo-mode cyclizations. 4-Oxepenes could also be formed from 4,6-heptadien-1-ols; the presence of a substituent on the carbon 6 appeared necessary, while for steric reasons the presence of a substituent on the carbon 7 was unfavorable. Oxocanes could be obtained in moderate yields (18-27%).
Palladium-Catalyzed Reactions of Enol Ethers: Access to Enals, Furans, and Dihydrofurans
作者:Matthew G. Lauer、William H. Henderson、Amneh Awad、James P. Stambuli
DOI:10.1021/ol3028994
日期:2012.12.7
The palladium-catalyzed oxidation of alkyl enolethers to enals, which employs low loadings of a palladium catalyst, is described. The mild oxidation conditions tolerate a diverse array of functional groups, while allowing the formation of di-, tri-, and tetrasubtituted olefins. The application of this methodology to intramolecular reactions of alkyl enolethers containing pendant alcohols provides
Preparation of 2,7-dioxabicyclo[4.4.0]decane and 2,8-dioxabicyclo[5.4.0]undecane derivatives in five steps from dihydropyran are reported. Transformation of 3-bromo-2-allyloxepane into 2,7-dioxabicyclo-[5.4.0]-undecane is also described.
Intramolecular anodic olefin coupling reactions: the use of bis enol ether substrates
作者:Kevin D. Moeller、Luzviminda V. Tinao
DOI:10.1021/ja00029a036
日期:1992.1
In an effort to develop electrochemical methods for directly initiating oxidative cyclization reactions, the anodic oxidation of bis enol ether substrates has been examined. The reactions were found to lead to the formation of five-, six-, and seven-membered-ring 1,4-dicarbonyl equivalents. The reactions were not found to be useful for generating larger ring sizes. Both alkyl and silyl enol ether substrates were found to be compatible with the conditions required for carbon-carbon bond formation. Cyclic voltammetry studies indicated that the cyclizations were fast and that the reactions happened at or near the electrode surface. Finally, the cyclization reactions were shown to be compatible with the formation of quaternary carbons, even when carbon-carbon bond formation involved the generation of two vicinal quaternary carbons.
Synthesis of Fluorogenic Polymers for Visualizing Cellular Internalization
作者:Shane L. Mangold、Rachael T. Carpenter、Laura L. Kiessling
DOI:10.1021/ol800932w
日期:2008.7.17
The binding of a polymeric ligand to a cell surface receptor can promote its internalization. Methods to track and visualize multivalent ligands within a cell can give rise to new therapeutic strategies and illuminate signaling processes. We have used the features of the ring-opening metathesis polymerization (ROMP) to develop a general strategy for synthesizing multivalent ligands equipped with a latent fluorophore. The utility of ligands of this type is highlighted by visualizing multivalent antigen internalization in live B cells.
Reversing the Polarity of Enol Ethers: An Anodic Route to Tetrahydrofuran and Tetrahydropyran Rings