Palladium-Catalyzed Cross-Coupling Reactions in One-Pot Multicatalytic Processes
作者:Hélène Lebel、Chehla Ladjel、Lise Bréthous
DOI:10.1021/ja0733235
日期:2007.10.1
Palladium-catalyzedcross-couplingreactions have been investigated in multicatalytic processes to synthesize disubstituted alkenes and alkanes from carbonyl derivatives. The use of copper-catalyzed methylenation reactions is the key starting reaction to produce terminal alkenes which are not isolated, but submitted to further structure elongation. Not only is the isolation of the alkene intermediate
Scandium-Catalyzed Regio- and Stereospecific Methylalumination of Silyloxy/Alkoxy-Substituted Alkynes and Alkenes
作者:Masanori Takimoto、Saori Usami、Zhaomin Hou
DOI:10.1021/ja909126k
日期:2009.12.30
Various alkynes and alkenes having a tethered ether group undergo methylalumination reactions with unprecedented regio- and stereoselectivity in the presence of a cationic half-sandwich alkylscandium species as a catalyst. The oxygen atom of the ether group plays an important role in controlling the selectivity, possibly by coordinating to the metal center. Even when a bulky tertbutyl(diphenyl)silyloxy group is used as the tether group, there is no loss of selectivity.