Ionic liquids as a reusable media for copper catalysis. Green access to alkenes using catalytic olefination reaction
作者:Vasily M. Muzalevskiy、Aleksey V. Shastin、Namiq G. Shikhaliev、Abel M. Magerramov、Aytekin N. Teymurova、Valentine G. Nenajdenko
DOI:10.1016/j.tet.2016.09.050
日期:2016.11
It was demonstrated that ionicliquids are superb recyclable media for copper catalyzed reactions using catalytic olefination reaction as an example. As a result a novel green access to the halogenoalkenes was elaborated. Possibility to perform up to five reaction cycles without catalyst leaching and decreasing of the yield was demonstrated. A number of various ionicliquids was screened and 1-buty
A kinetic separation method for the stereoselective preparation of (Z)- and (E)-monofluoroenynes from E/Z mixtures of 1-bromo-1-fluoroolefins
作者:Xin Zhang、Donald J. Burton
DOI:10.1016/s0022-1139(01)00529-2
日期:2001.12
under similar conditions and longer reaction times (48 h) to give pure (E)-monofluoroenynes in excellent yields (78–89%). Thus, E/Z mixtures of 1-bromo-1-fluoroolefins could be kinetically separated into (Z)- and (E)-monofluoroenynes. This methodology provides a simple one-step unequivocal route to the isomerically pure (Z)- and (E)-monofluoroenynes from the readily available 1-bromo-1-fluoroolefins.
Stereospecific preparation of (Z)-α-fluorostilbenes via a kinetically controlled palladium-catalyzed cross-coupling reaction of high E/Z ratio 1-bromo-1-fluorostyrenes and aryl stannanes
作者:Jianjun Xu、Donald J Burton
DOI:10.1016/s0040-4039(02)00357-x
日期:2002.4
for 1-bromo-1-fluorostyrenes by isomerization from the original E/Z ratios of approximately 1:1. The palladium-catalyzed cross-coupling reaction of high E/Z ratio 1-bromo-1-fluorostyrenes with aryl stannanes gives (Z)-α-fluorostilbenes stereospecifically in good yields.
A kinetic separation method for the stereoselective preparation of 1-fluorovinylphosphonates from E/Z mixtures of 1-bromo-1-fluoroolefins
作者:Xin Zhang、Donald J. Burton
DOI:10.1016/s0022-1139(01)00482-1
日期:2001.11
Reaction of E/Z mixtures of 1-bromo-1-fluoroolefins with diethylphosphite and catalytic Pd(PPh3)4 in triethylamine at 30–40°C gave predominately the (E)-isomer of the 1-fluorovinylphosphonate (E/Z≥95:5) in good yields. Pure (E)-1-fluorovinylphosphonate could be readily obtained by chromatographic separation of the 95:5 E/Z mixture. Pure (Z)-1-bromo-1-fluoroolefin could be recovered and phosphorylated
A halon-free method for the synthesis of ‑bromofluoroolefins utilizing ethyldibromofluoro-acetate is disclosed via a Wittigtypereaction. The reaction system takes advantage of inexpensive and readily available reagents. The method was applied to a wide variety of aryl aldehydes. Both electron donating and electron withdrawing moieties on the aryl ring were tolerated and the desired olefin products