Highly stereocontrolled synthesis of trans-enediynes via carbocupration of fluoroalkylated diynes.
Treatment of readily prepared (Z)-6-benzyloxy-1,1,1,2-tetrafluoro-6-methyl-2-hepten-4-yne with 1.5 equiv of LHMDS in -78 °C for 1 h gave the corresponding trifluoromethylated diyne in an excellent yield. This diyne was found to be a good substrate for the carbocupration with various higher-ordered cyanocuprates to give the corresponding vinylcuprates in a highly regio- and stereoselective manner. The in situ generated vinylcuprates could react very smoothly with an excess amount of iodine, the vinyl iodides being obtained in high yields. Thus-obtained iodides underwent a very smooth Sonogashira cross-coupling reaction to afford various trans-enediynes in high yields.
Department of Chemistry and Materials Technology, Kyoto Institute of Technology, Matsugasaki, Sakyo-ku, Kyoto 606-0962, Japan.
Tsutomu
T
Konno
Misato
M
Kishi
Takashi
T
Ishihara
carbocupration; carbometallation; diyne; enediyne; fluorine; highly regioselective; highly stereoselective