Ionic Liquid, Surrogate Hydrogen Bromide Reagent for Ring Opening of Cyclopropyl Ketones
作者:Wei Xu、William R. Dolbier、Jose Salazar
DOI:10.1021/jo800337t
日期:2008.5.1
Ionic liquid reagents created by addition of 1 equiv of either CF3CO2H or CF3SO3H to N-pentylpyridinium bromide exhibit excellent chemical reactivities as surrogate HBr reagents in ring-opening reactions of cyclopropyl ketones as well as of 2,2-difluorocyclopropyl ketones to form the respective 3-bromopropyl or 3-bromo-2,2-difluoropropyl ketones in good to excellent yields.
通过将1当量的CF 3 CO 2 H或CF 3 SO 3 H加到N-戊基吡啶溴化物中而形成的离子液体试剂具有极好的化学反应性,在环丙基酮和2,2的开环反应中可替代HBr试剂。 -二氟环丙基酮以良好至优异的产率形成各自的3-溴丙基或3-溴-2,2-二氟丙基酮。
Reaction of difluorocarbene with propargyl esters and efficient synthesis of difluorocyclopropyl ketones
Difluorocarbene generated from FSO2CF2CO2SiMe3 (TFDA) at 120 °C could reacted with terminalalkynes having an ester group at the αposition to the triplebond. Difluorocyclopropenes were further converted to difluorocyclopropyl ketones under alkaline condition. Mechanism for the conversion was studied.
由FSO 2 CF 2 CO 2 SiMe 3(TFDA)在120°C下生成的二氟卡宾可以与在三键的α位具有酯基的末端炔烃反应。在碱性条件下,将二氟环丙烯进一步转化为二氟环丙基酮。研究了转化机理。
Friedel−Crafts Reactions of 2,2-Difluorocyclopropanecarbonyl Chloride: Unexpected Ring-Opening Chemistry
作者:William R. Dolbier、Eric Cornett、Henry Martinez、Wei Xu
DOI:10.1021/jo200423y
日期:2011.5.6
3-difluoropropyl ketones. The ring-opened product was formed exclusively, and therefore the reaction may be synthetically useful when relatively unreactive arene substrates such as benzene, toluene, and p-xylene are used. No conditions were found where ring-intact products could be formed exclusively when using substituted benzenes as substrates, with the very reactive substrate thiophene being most selective in that
The CF3SO3H-promoted ring opening of gem-difluorocyclopropyl ketones prefers to undergo proximal bond cleavage and the subsequent cyclization with nitriles occurred smoothly to give 2-fluoropyrroles.
Dehydrative Ring‐Opening of
<i>gem</i>
‐Difluorocyclopropyl Carbinols to Allylic Trifluoromethyl and Difluorohalomethyl Derivatives Promated by Titanium Tetrahalide
An effective approach to (E)‐allylic CF3, (E)‐allylic CF2Cl, (E)‐allylic CF2Br derivatives, 1‐chloro‐2,2‐difluoromethylene, and polyfluorinated compounds has been developed, based on a titanium tetrahalide‐promoted dehydrative ring‐opening of gem‐difluorocyclopropyl carbinols.