A series of 1,4-enynes was prepared and the compounds metalated with butyllithium in ether. The formation of the mono- and dilithio derivatives was studied by PMR and UV. Protonation of the dilithio compounds gave vinylallenes, 1,3- and 1,4-enynes. Isomerisation of the 1,4-enynes in DMSO using dimsylsodium gave vinylacetylenes from compounds containing a terminal double bond and vinylallenes from those
Direct and Stereospecific Synthesis of Allenes via Reduction of Propargylic Alcohols with Cp<sub>2</sub>Zr(H)Cl
作者:Xiaotao Pu、Joseph M. Ready
DOI:10.1021/ja8035527
日期:2008.8.1
Allenes can be synthesized via the direct SN2' addition of hydride to propargylicalcohols. Previous examples of this approach, however, have involved harsh reaction conditions and have suffered from incomplete transfer of central chirality to axial chirality. Here we show that Cp2Zr(H)Cl can react with the zinc or magnesium alkoxides of propargylicalcohols to generate allenes in good yield and in
Palladium‐Catalyzed Reductive [5+1] Cycloaddition of 3‐Acetoxy‐1,4‐enynes with CO: Access to Phenols Enabled by Hydrosilanes
作者:Li‐Jun Wu、Ren‐Jie Song、Shenglian Luo、Jin‐Heng Li
DOI:10.1002/anie.201808388
日期:2018.10
cycloaddition of 3‐acetoxy‐1,4‐enynes with CO, enabled by hydrosilanes, has been developed for delivering valuable functionalized phenols. This methodology employs hydrosilanes as the external reagent to facilitate the [5+1] carbonylative benzannulation. The reaction is a conceptually and mechanistically novel carbonylative cycloaddition route for the construction of substituted phenols, through the