the synthesis of alkenyl halides are described under microwave-assisted conditions. The reaction proceeds through the condensation between sec-alcohols and terminalacetylenes and regeoselective hydro halogenation across the triple bond in the presence of simple and commercially available zinc halides. Three halide sources could successfully be employed to give a diverse range of alkenyl halide products
Zinc-Mediated Regiodiverse Synthesis of Vinyl Bromide Derivatives and Their in situ Palladium-Catalysed Cross-Coupling Reactions
作者:Gerhard Hilt、Anne Miersch、Corinna Kohlmeyer
DOI:10.1055/s-0033-1339616
日期:——
zinc-mediated addition of a benzylic bromide to a terminal alkyne. The geometry of the C=C bond is dependent on the amount of zinc powder applied. When 5 mol% of Zn is used, the Z-configured vinyl bromide is generated while with 150 mol% the E-geometry is obtained predominantly. In a three-component one-pot reaction, the in situ generated vinyl bromides were reacted further in a palladium-catalysed Suzuki
Stereodivergent Zinc-Mediated Three-Component Synthesis of Tri- and Tetrasubstituted Alkenes
作者:Anne Miersch、Gerhard Hilt
DOI:10.1002/chem.201201385
日期:2012.8.6
Zinc simple: The loading‐dependent zinc‐mediated addition of benzyl bromides to alkynes is the key step for the formation of vinyl bromides. In combination with a palladium‐catalyzed Suzuki cross‐coupling reaction with boronic acids, tri‐ and tetrasubstituted alkenes were obtained in good yields and stereoselectivities in a one‐pot protocol (see scheme).
Boron Trihalide Mediated Substitution of Hydroxyl Groups with Alkenyl, Alkynyl, and Allyl Moieties
作者:George Kabalka、Scott Borella、Min-Liang Yao
DOI:10.1055/s-2007-990816
日期:2008.1
The coupling of alcohols with alkenyl- and alkynylboron dihalides with high olefin stereoselectivity is described. The reaction provides a facile route to internal acetylenes. Notably, the allylation of propargylic alcohols mediated by borontrichloride proceeds smoothly at room temperature and gives excellent regioselectivity.
FeX<sub>3</sub>-Promoted Intermolecular Addition of Benzylic Alcohols to Aromatic Alkynes: A Mild and Efficient Strategy for the Synthesis of Alkenyl Halides
作者:Kai Ren、Min Wang、Lei Wang
DOI:10.1002/ejoc.200901020
日期:2010.1
A convenient, effective, mild and simple strategy has been developed for the synthesis of alkenyl halides by the intermolecular addition of benzylic alcohols to aromatic alkynes. The reactions were carried out in the presence of iron(III) bromide or chloride in 1,2-dibromoethane without additives in air at room temperature. Alkenyl bromides and chlorides were obtained with high regio- and stereoselectivity