On the mechanism of titanocenedichloride-catalysed hydromagnesiation of alkynes with alkyl Grignard reagents
作者:Yuan Gao、Fumie Sato
DOI:10.1039/c39950000659
日期:——
The mechanism of titanocenedichloride-catalysed hydromagnesiation reaction of alkynes with an alkyl Grignard reagent is elucidated and it is revealed that the regiochemistry of the reaction controlled at the step of transmetallation from titanium to magnesium.
Halogen-magnesium exchange of various aryl halides is achieved with a magnesium ate complex at low temperatures; Tributylmagnesate ((Bu3MgLi)-Bu-n) induces facile iodine-magnesium exchange at -78 degreesC. Dibutylisopropylmagnesate ((PrBu2MgLi)-Pr-i-Bu-n) is more reactive than (Bu3MgLi)-Bu-n, and this reagent accomplishes selective bromine-magnesium exchange at -78 degreesC. This procedure is utilized for the preparation of various polyfunctionalized arylmagnesium species. The exchange of alkenyl halides using this method proceeds with retention of configuration of the double bond.
Stereo- and Regioselective Generation of Alkenylzinc Reagents via Titanium-Catalyzed Hydrozincation of Internal Acetylenes
作者:Yuan Gao、Kousuke Harada、Takeshi Hata、Hirokazu Urabe、Fumie Sato
DOI:10.1021/jo00107a003
日期:1995.1
IKENAGA KAZUTOSHI; KIKUKAWA KIYOSHI; MATSUDA TSUTOMU, J. ORG. CHEM., 52,(1987) N 7, 1276-1280