Ruthenium(IV)-Catalyzed Markovnikov Addition of Carboxylic Acids to Terminal Alkynes in Aqueous Medium
作者:Victorio Cadierno、Javier Francos、José Gimeno
DOI:10.1021/om1010325
日期:2011.2.28
promote the selective Markovnikov addition of both aromatic and aliphatic carboxylic acids to a large variety of terminal alkynes, enynes, and diynes as well as propargylicalcohols. In this way, a wide number of enol esters and β-oxoesters could be synthesized in moderate to good yields under mild conditions (60 °C) in an aqueous medium.
The direct addition of in situgenerated hydrazoic acid to alkynes is realized without solvent by using a gold catalyst derived from a recently designed remotely functionalized biaryl-2-ylphosphine ligand (i.e., WangPhos). With terminal alkynes, the additions are mostly realized with 0.1 mol% catalyst loadings and at 40 °C. With more challenging internal alkynes devoid of direct EWG substitution, the
The synthesis and characterization of original NHC ligands based on an imidazo[1,5‐a]pyridin‐3‐ylidene (IPy) scaffoldfunctionalized with a flanking barbituric heterocycle is described as well as their use as tunable ligands for efficient gold‐catalyzed C−N, C−O, and C−C bond formations. High activity, regio‐, chemo‐, and stereoselectivities are obtained for hydroelementation and domino processes,
描述了以侧翼巴比妥杂环为功能的咪唑并[1,5 - a ]吡啶-3-亚烷基(IPy)支架为基础的原始NHC配体的合成和表征,以及它们作为有效金催化C的可调配体的用途。 -N,CO和CC键形成。在加氢元素化和多米诺骨牌工艺中获得了高活性,区域选择性,化学选择性和立体选择性,这突显了这些基于IPy的配体在金催化中的出色性能(TON和TOF)。1,6-烯炔的金催化多米诺反应在温和的条件下以优异的分离产率产生了官能化的杂环。NHC金牌5 Me的效率配合物是显着的,主要是由于配位体1 Me对阳离子Au I活性物质的空间保护和稳定作用的结合。