We present an approach to utilize water as the hydride source via Pd(II)/Pd(0) catalysis. As a case study, we have achieved a diboron mediated Pd(II)-catalyzed hydroarylation of alkynes using arylboronic acids. This approach not only complements conventional reactivity of Pd via Pd(0)/Pd(II) cycle for the hydroarylation but also utilizes water as the hydride source. We believe this would particularly
Straightforward Iron-Catalyzed Synthesis of Vinylboronates by the Hydroboration of Alkynes
作者:Michael Haberberger、Stephan Enthaler
DOI:10.1002/asia.201200931
日期:2013.1
An iron‐catalyzed hydroboration of alkynes to produce vinylboronates has been examined. With a straightforward system composed of iron carbonyls and pinacolborane, good to excellent yields and chemoselectivities were achieved for a variety of alkynes.
The palladium-catalyzed hydroarylation of arenediazonium tetrafluoroborates with alkynes in the presence of triphenylsilane affords stereoselectively hydroarylation products in moderate to high yields. The reaction tolerates a variety of substituents including keto, ester, cyano, and nitro groups and can be performed as a one-pot procedure generating the arenediazonium salt in situ. With ethyl phenylpropynoate as the starting alkyne, the hydroarylation affords ethyl (2)-2-arylcinnamates stereo- and regioselectively.