to produce unisolable allylchromium species which add efficiently to aldehydes or ketones with high degree of stereo- and chemoselectivity. Particularly, high threo selectivity is observed in the reaction of aldehydes and 1-bromo-2-butene and is ascribed to a chair-like six-membered transition state. Simple reduction of allylic and benzylic halides produces biallyls and bibenzyls, while gem-dibromocyclopropanes
An Efficient Electrochemical Coupling of Allylic Halides by Using a Copper Anode
作者:Masao Tokuda、Kazuhiro Endate、Hiroshi Suginome
DOI:10.1246/cl.1988.945
日期:1988.6.5
A new electrolytic method for an efficient coupling of allylichalides by the use of a copper anode and a platinum cathode in the presence of sodium iodide is described. A method which avoids a loss of the copper anode owing to dissolution is also described.
Thermische stabilität von Bis(alk-2-enyl)zink-Verbindungen
作者:Herbert Lehmkuhl、Ingo Döring、Hans Nehl
DOI:10.1016/s0022-328x(00)81023-2
日期:1981.11
The dialk-2-enylzinc compounds I–III react slowly at 20 to 50°C by addition of the ZnC bond to the CC bond of an alk-2-enyl group to give oligomers from which the alkenes XIII–XV are released on hydrolysis. For I–III homolytic cleavage of the ZnCallyl bond, followed by coupling of the allyl radicals to give the alkadienes V–VII, IX and XI predominates above 50°C. IV decomposes mainly homolytically