开发了三齿 PSiP 钳形钯配合物在二氧化碳下催化丙二烯加氢羧化,得到合成有用的 β, γ-不饱和羧酸。这种新型的 CO2 固定反应被认为是通过丙二烯的氢化钯催化生成 σ-烯丙基钯物种,然后在适当的还原剂存在下将其区域选择性亲核加成到 CO2 中进行的。该反应成功应用于带有酯、氨基甲酸酯、酮和烯烃等官能团的各种丙二烯,显示出该方案的高合成效用。
开发了三齿 PSiP 钳形钯配合物在二氧化碳下催化丙二烯加氢羧化,得到合成有用的 β, γ-不饱和羧酸。这种新型的 CO2 固定反应被认为是通过丙二烯的氢化钯催化生成 σ-烯丙基钯物种,然后在适当的还原剂存在下将其区域选择性亲核加成到 CO2 中进行的。该反应成功应用于带有酯、氨基甲酸酯、酮和烯烃等官能团的各种丙二烯,显示出该方案的高合成效用。
A simple protocol for hydrodebromination and ‐deiodination of halo(hetero)arenes was enabled by sodium hydride (NaH) in the presence of lithium iodide (LiI). Mechanistic studies showed that an unusual concerted nucleophilic aromatic substitution operates in the present process.
Regio- and Enantioselective Rhodium-Catalyzed Addition of 1,3-Diketones to Allenes: Construction of Asymmetric Tertiary and Quaternary All Carbon Centers
作者:Thorsten M. Beck、Bernhard Breit
DOI:10.1002/anie.201610577
日期:2017.2.6
An unprecedented highly regio‐ and enantioselective rhodium‐catalyzed addition of 1,3‐diketones to terminal and 1,1‐disubstituted allenes furnishing asymmetric tertiary and quaternary all‐carboncenters is reported. By applying a RhI/phosphoramidite/TFA catalytic system under mild conditions, the desired chiral branched α‐allylated 1,3‐diketones could be obtained in good to excellent yields, with perfect
据报道,前所未有的高度区域和对映体选择性的铑催化向末端和1,1-二取代的丙二烯加成1,3-二酮,提供不对称的叔碳和季碳全中心。通过在温和的条件下应用Rh I /磷酰胺/ TFA催化体系,可以获得所需的手性支链α-烯丙基化的1,3-二酮,收率好至极好,具有良好的区域选择性和高对映选择性。该反应在两个反应伙伴上均显示出广泛的官能团耐受性,从而突出了其合成潜力。
Cobalt‐Catalyzed Regio‐ and Stereoselective Hydroboration of Allenes
作者:Can Li、Zheng Yang、Lei Wang、Yinlong Guo、Zheng Huang、Shengming Ma
DOI:10.1002/anie.201915716
日期:2020.4.6
pincer-ligand-based cobalt-complex-catalyzed allenehydroboration affording Z-allylic boronates is described. The reaction demonstrates an excellent regio- as well as Z-stereoselectivity and a wide substrate scope that tolerates many functional groups. Based on solvent-assisted electrospray ionization mass spectrometry (SAESI-MS) studies, a rationale for the cobalt-catalyzed hydroboration involving the highly selective
new cobalt-catalyzed phenolic OH-assisted C–H functionalization of 2-vinylphenols with allenes to give various 2H-chromenes is described. It is the first time that allenes are used as the coupling partners in the cobalt-catalyzed C–H activation reactions. In most cases, cobalt-catalyzed oxidative annulation of arenes with alkenes or alkynes via C–H activation gave [4 + 2] or [3 + 2] cyclization products
The electrophilic amination of allylic boranes, which are prepared from allenes and 9-borabicyclo[3.3.1]nonane (9-BBN), with azodicarboxylates as an aminating reagent is reported. 9-BBN-based allyl...